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paragon
11-21-2004, 03:01 PM
Just bought a K 145 on Ebay. Price was 145 USD including shipping. Sorry, lost the other one (was to late), so i get only one :mad:
What do you think about this speaker ?
I think it`s one of the best you can get from JBL (similar to 150C, underhang voice coil, large alnico, rare).

Eckhard

pangea
11-26-2004, 11:06 AM
I had a pair of those, mounted in a pair of 4530's back in the seventies. You can't eveven begin to imagine how many times I've regretted selling them, just as I regretted having sold my L300's some years later.:banghead: :banghead: :banghead: :banghead:

/Roland

paragon
11-26-2004, 12:17 PM
/Yes Roland,

Feel with you. I think this is one of the most expensieve bass drivers JBL ever build.
Waiting for it. The guy who sold this had four of this and i need another one.
When i bought my four 2205A in 79/80 the price for the K145 was only 50 DM higher than the 2205 (2205= 425 DM, K145= 475 DM).
But you sold a pair L300 ???? Oh God, what a mistake !!

Eckhard:(

paragon
11-26-2004, 12:20 PM
Whats that speaker in your avatar ? Pics please.

Eckhard

pangea
11-26-2004, 12:25 PM
/Yes Roland,

Feel with you. I think this is one of the most expensieve bass drivers JBL ever build.
Waiting for it. The guy who sold this had four of this and i need another one.
When i bought my four 2205A in 79/80 the price for the K145 was only 50 DM higher than the 2205 (2205= 425 DM, K145= 475 DM).
But you sold a pair L300 ???? Oh God, what a mistake !!

Eckhard:(

I KNOW!!! I deserve a real horse whipping!!!
Why do you think I had to post four of the banging heads on the brick wall?

:banghead: :banghead: :banghead: :banghead: It still hurts!!!
I even sold them cheap to an old friend whom I lost contact with, some ten years ago.

/Roland

paragon
11-26-2004, 12:42 PM
A few years ago an old man sold his L300 for only 1200 DM. I was to late :( .
The bassdrivers where reconed by Harman Deutschland !!!
Lucky man bought this.
The old man bought Wilson Watt puppy (?). Sh.. Small speakers for much money.

Eckhard

pangea
11-26-2004, 01:06 PM
A few years ago an old man sold his L300 for only 1200 DM. I was to late :( .
The bassdrivers where reconed by Harman Deutschland !!!
Lucky man bought this.
The old man bought Wilson Watt puppy (?). Sh.. Small speakers for much money.

Eckhard
A few years after I sold my L300's, the Swedish representative, whom I knew and had helped few times at various HiFi-shows, phoned me and said that one of his customers were selling his Paragon for 15000SEK, roughly 1500€, a bargain even in the late seventies.
But when I got there with the money in my hand, the Paragon had been already sold to another person, only 15 minutes earlier!!!

Do you think that did hurt me???:banghead: :banghead: :banghead: :biting: :biting: :biting: :bomb: :bomb: :bomb:

So, it seems we share a few common experiences.


/Roland

paragon
11-26-2004, 01:09 PM
Yes, but its gone. We can`t change.
Show me your avatar, please and describe(?).

Eckhard

pangea
11-26-2004, 01:38 PM
Yes, but its gone. We can`t change.
Show me your avatar, please and describe(?).

EckhardYou're absolutely right! No sence in crying over it now!

The speakers are DIY and consist of a Urei 2215H in a larger part of the cabinet and it takes care of the deep end from 25Hz to 61Hz, then there is a JBL2225H using a smaller part, taking care of the mid-bass, right now up to 691Hz, (bypassing the 2110A and the built in 075 at the moment), going straight to the JBL2445J with a Selenium horn and a 075, placed on top of the DIY speaker, as shown on the pics.

All drivers are crossed over by a pair of Behringer UltraDrive DCX2496 and then hooked up to a couple of DIY Hypex class-D UcD180 and a UcD400 amps, which by the way, I'm very happy with.

The building of these amps has occupied much of my time this smmer and fall and that's why I have been absent from the forum for a While.

After these pictures were taken, there has been a few minor changes though.

http://img.photobucket.com/albums/v421/pangea2012/Vnster.jpg

http://img.photobucket.com/albums/v421/pangea2012/hger.jpg

http://img.photobucket.com/albums/v421/pangea2012/uppifr.jpg


EDIT: BTW! I have a pair of 2441's coming my way, which I am going to try to replace the 2110 with. The 2441 will also be mounted on a a Selenium horn and then it should fit in the hole after some moulding in fiber-glass within the sub-chamber for the 2110.

/Roland

paragon
11-26-2004, 01:47 PM
Yes , i see the two 2215, but where is the 2225 ?
Very interesting power amp under your tv !!

Eckhard

paragon
11-26-2004, 01:53 PM
You get power at 25 Hz with this drivers ?? Can`t believe.
Second pic : much elko`s. What´s this?

Eckhard

pangea
11-26-2004, 01:57 PM
Yes , i see the two 2215, but where is the 2225 ?
Very interesting power amp under your tv !!

Eckhard
OK, what seems to be two identical 15" drivers are in fact one of each. If you look again at the vent-holes, you'll see that they are tuned differently.

The big amp is a Yamaha PC2602M, which I bought from the Royal "Dramaten" theatre in Stockholm. It's a very nice amp and even more so, after I've added an extra 12V PC-fan driven with a 9V supply. This made the amp completely silent at all times.

/Roland

pangea
11-26-2004, 02:00 PM
You get power at 25 Hz with this drivers ?? Can`t believe.
Second pic : much elko`s. What´s this?

Eckhard
I don't quite follow.

Could you elaborate?

/Roland

paragon
11-27-2004, 09:19 AM
Is that a power supply in the third picture ?
And do you get real 25 Hz with this bass drivers ?

Eckhard

pangea
11-27-2004, 05:06 PM
Is that a power supply in the third picture ?
And do you get real 25 Hz with this bass drivers ?

Eckhard
It's not only a very hefty power supply, it's also a complete DIY amp. It has also two Class-D Hypex UcD400 modules (2*400W) behind the large Rifa capacitors, but these modules are so small that they don't even show on the picture.:D Still the total weight is 16,5Kg.

I'm not absolutely sure how deep they go, but it can't be that far off from the 25Hz mark, according to what the UltraCurve tells me. The cabs for the 2215H are also tuned to 25Hz.

Do you by any chance have the spec's on the UREI 2215H? I've looked everywhere, but never found any.

/Roland

paragon
11-28-2004, 03:08 AM
No, sorry.

Eckhard

Robh3606
11-28-2004, 07:36 AM
Urei 2215 is the same driver as the JBL. You can use the T/S for the 2215.

Rob:)

pangea
11-28-2004, 01:13 PM
Urei 2215 is the same driver as the JBL. You can use the T/S for the 2215.

Rob:)

OK, thanks, I was hoping for that, but wasn't sure. So is there no difference whatsoever between them?

Roland

Don McRitchie
11-28-2004, 01:52 PM
The UREI version is the "H" or ferrite magnet conversion of the previous 2215B/LE15A. This was the same driver that JBL labeled as the LE-15H in the Paragon after 1979. The UREI 2215H only became part of the 813C monitor after JBL bought UREI and they just substituted drivers from their own inventory. Therefore, it is identical to the JBL 2215H for which T/S parameters are listed here:

http://www.lansingheritage.org/images/jbl/reference/notes/tech1-3a/page09.jpg

pangea
11-29-2004, 01:30 PM
The UREI version is the "H" or ferrite magnet conversion of the previous 2215B/LE15A. This was the same driver that JBL labeled as the LE-15H in the Paragon after 1979. The UREI 2215H only became part of the 813C monitor after JBL bought UREI and they just substituted drivers from their own inventory. Therefore, it is identical to the JBL 2215H for which T/S parameters are listed here:

http://www.lansingheritage.org/images/jbl/reference/notes/tech1-3a/page09.jpg
Thank you for the info! But he 2215H wasn't on the list, perhaps it's on a previous page, or is it the values on the LE15A I should look for?

Roland

paragon
11-30-2004, 10:45 AM
Get the old K145 today. No good condition. The cone is ok and the speaeker
works, but the surround has some nicks(?). The polplate is rusty and i have to restore this driver.
What is this black "glue" the dustcap and the surround is fixed with ??
Shall i use speaker-treatment (for cone damping)to restore the surround ?
Cone and surround is build frome one piece moulded paper, so i think this is an very old one. Later build drivers are made with cloth surrounds ?
Serial number is 15577.
Can anybody help restore this surround ? Pics later.

Eckhard

paragon
12-01-2004, 10:38 AM
Backside, rust, dirty

paragon
12-01-2004, 10:40 AM
Front, cone ok, surround bad

paragon
12-01-2004, 10:44 AM
Some bad parts

Earl K
12-01-2004, 11:11 AM
Hi Eckhard

Really , that K145 looks a lot better than the initial impression that I had gotten .

Nice speaker, I wish I had a couple of those K145s ( yes it is indeed a sickness ) .
If I had a pair - I'd look into putting foam surrounds on them to create a hybrid le15/K145 thingy-dingy with a lower Fs ( like 27hz ). I'd also treat the cones to add a bit of mass. This might of course, be a direct route towards , two premature reconings :rotfl:

Now seriously, I can't really see "the problems" you've mentioned .

Does the surround have some long ( circular ) splits in it , somewhere ?
- I can't see any . Most times, for home use, these splits can be fixed by one means or another .

Maybe start a thread about fixing surround-splits . The older forums used to have quite a few. Cigarette papers and white-glue comes to mind , etc.

Damping "goo" can be obtained from experienced long-time reconers - just don't expect to mooch all this repair stuff for free. ElectroVoice used to have a goop that they treated their own foam surrounds with . It "looked" like white glue before application - but cured/dried? "clear" and flexible,. It was able to maintain the compliance of the foam surround. Audax would need to have something similar for all their foam-surround hifi transducers .

What are you going to use these speakers for ?

<. Earl K

Don McRitchie
12-01-2004, 11:45 AM
Thank you for the info! But he 2215H wasn't on the list, perhaps it's on a previous page, or is it the values on the LE15A I should look for?

Roland
My mistake, it's on the previous page. You can access all of the pages from here:

http://www.lansingheritage.org/html/jbl/reference/notes/tech1-3a.htm

paragon
12-01-2004, 12:22 PM
Hello Earl,

There are no holes or splits in the surround. Only dirt, i can`t remove and some lost of paper and this black viscous glue (like tar ?).
So i just want to restore it with this black glue or damping material.
But where can i get this ?
Yes, have to remove the rust from the polplate and have to paint the basket and magnet pot black.
Try to fix this driver in my 4530 (40,5 cm Dia !!)?
I only get one of this rare thing. Hard to get here in Germany. Two weeks ago there where three in Ebay and i lost two.
The first was sold for only 92 Euro (115 USD?). The guy who sold this has another fixed in his old enclosure. Hope to get this too.
A german "friend" in Berlin has the newer E145 and i said to him "Doen`t sell this drivers !"

Eckhard

scott fitlin
12-01-2004, 12:42 PM
Theres nothing wrong with the older style surround, it works quite well. You can restore it by applying a coat of viscous damping fluid! Call JBL and get a bottle of the stuff, and you will pay for it but this is what you use.

From the looks of your pictures theres not much really wrong with your surround, other than aged looks and some crud!

Fix it up, and listen to it in its original state to see what you hear, BEFORE you decide to re engineer the speaker! You might be surprised what you hear! If, after you have listened to the K145 in its original state, decide you think you need to alter the Fs, change the type of surround, etc, then you can do what you want. But listen to it first!

Earl K
12-01-2004, 12:48 PM
Hello Earl,
There are no holes or splits in the surround. Only dirt, i can`t remove and some lost of paper and this black viscous glue (like tar ?).

Ohhh, well that's good. Personally when it comes to dirt and grime in the pleats of the surround - the only way I know to clean it out is by using ones' fingers or tweezers. I also use those "locking" type surgical tools ( hemo???? - I forget the real name, off-hand ) .



So i just want to restore it with this black glue or damping material.
But where can i get this ?
Well, If you just pick out the dirt pieces ( may take a month in front of the TV ) then you won't need to restore anything - unless the surround is all dried up and brittle . Is it still a bit "tacky" ?

- There are some reconers who frequent this forum , they may have better ideas for you. Anyone ???
- They may also know the name ( product number ) of the Waldom goop to buy, to put onto those surrounds ..

<> Earl K

paragon
12-01-2004, 12:48 PM
Tanks Earl and Scott,

I will ask Harman Deutschland or Guido (in German) for this stuff.
Yes Scott, the surround is still working an i only want to "paint" it with this "glue".
No new suorround and nothing else.

Eckhard

paragon
12-01-2004, 12:52 PM
OK Earl,

You where faster than me.
Youst wait.

Eckhard

Earl K
12-01-2004, 12:56 PM
Fix it up, and listen to it in its original state to see what you hear, BEFORE you decide to re engineer the speaker!

Good sound advice , Scott . :yes:

Do you have any K145s in your park-systems or have you heard them in an Altec 816 cabinet ?

regards <. Earl K

Youst wait.

Okay, but ,,, ?

paragon
12-01-2004, 01:02 PM
What the hell is DIY ?? Sorry?

The pre-driver named 150C or C4 has the same cone or not ?
But the K145 has also the deep mag gap and the underhang coil,
so it´s better than the old 150C ??

Eckhard

paragon
12-01-2004, 01:05 PM
for answers of "reconers", Earl

Eckhard

Earl K
12-01-2004, 01:18 PM
What the **** is DIY ?

It's just an acronym,,, :yes:

DIY = Do It Yourself. :cheers:


The pre-driver named 150C or C4 has the same cone or not ?
I don't know , maybe Oldmics does ,,,

But the K145 has also the deep mag gap and the underhang coil,
so it´s better than the old 150C ??
Well, these days I'm more interested in the topology that is represented by the K145.
- I don't believe there is such a thing as "best". All the different topologies have their respective strengths and weaknesses .


Youst wait. ---- for answers of "reconers",

Okay, now I'm lost .
<. Earl K

scott fitlin
12-01-2004, 01:25 PM
Good sound advice , Scott . :yes:

Do you have any K145s in your park-systems or have you heard them in an Altec 816 cabinet ?

regards <. Earl K


Okay, but ,,, ?I dont have any 145,s in here, but Ive heard them many times and they rock, they got that sound I like!

Im told the K-145 would be the closest to the 150-4C, I have never heard a 150 so I cant say for sure! Its a similar style speaker, from the looks of them!

Im more familiar with the E series of these speakers, and to me, they are great too!

:)

paragon
12-01-2004, 01:34 PM
I also think this driver is similar to the 150 exept the mag and coil.
So i think (Earl) this driver must be better than the old 150.

Eckhard

scott fitlin
12-01-2004, 05:19 PM
I also think this driver is similar to the 150 exept the mag and coil.
So i think (Earl) this driver must be better than the old 150.

EckhardI would guess the gap and coil were updated to handle higher power! This is what they were doing in the early to late 70,s.

Just my guess.

paragon
12-11-2004, 09:35 AM
Front side 1

paragon
12-11-2004, 09:37 AM
Front side 2

paragon
12-11-2004, 09:38 AM
Last pic

Earl K
12-11-2004, 11:24 AM
Wow, Fantastic !

Now, what's your secret ?

Did you actually recone that K145 or spend 10 days "surgically" removing all the lint and dirt pieces ?

Of course, pictures like these give me a case of "woofer-envy" . :D :yes:

regards < Earl K :cheers:

pangea
12-11-2004, 12:46 PM
Wow, Fantastic !


...Of course, pictures like these give me a case of "woofer-envy" . :D :yes:

regards < Earl K :cheers:
ME TOO!!!:D

I had a pair of K145's in the seventies, mounted in a pair of 4530's and yes they rocked my world.

Still think I shot myself in the foot, selling them many years ago.:banghead:

BR
Roland

Earl K
12-11-2004, 01:19 PM
Still think I shot myself in the foot, selling them many years ago.
Roland,
Yea, but at least you've got those nice 2215 woofs -which are part of the same "underhung" voice-coil family, which the K145 belongs to. :rockon1:

Ever thought of making up some MTM setups with all your stuff ? :thmbsup:

- I'd put the 2215(s)/K145(s) in 3 to 4 cu' "top" boxes ( for their superb bass and midbass performance ) while running a 2235h in a larger 5 cu' box underneath ( all the while getting its' great / authoritative bass ) . Volume for you metric guys ; 113.267 litres and 141.584 litres . Use the Selenium horn/2441 that you already have, if its coverage-pattern works for your listening setup .
- This becomes a "Legacy" driven , K2 type "thingey" .


regards <. Earl K :D

paragon
12-11-2004, 01:24 PM
No secrets Earl and Roland,

Work was about 6-8 Hours during the last two weeks.
First cleaned all with a wet leather(?). Then cleaned the polplate from rust with a small brass bush and a minidrill.
Paint the basket and then the Magnet part with a thin layer of black.
After drying paint the paper surround with a very thin layer of bitumen (car).
Sprayed it into a glass and used a thin brush. Coverd the cone with an 11 inch dia thick paper to get a good round circle.
Impossible to remove the dust and dirt from the surround. So the driver looks very good now. Thats all.

Eckhard

Earl K
12-11-2004, 01:31 PM
Really Beautiful Work Eckhard ! :spin: :cheers: :spin:

Now of course I'm jealous, but I'll just have to get over it - I guess . :hyp:

What are you going to do with this K145 ?

regards <. Earl K :wave:

paragon
12-11-2004, 01:51 PM
Mmmhh, i only have one of this very nice drivers at this moment.
Hope to get the last one from the man who sold this. Want to put them in my 4530 and store the 2205A. Cleaned the outer non painted ring of the basket also with the brass brush and polished it with "chrome clean" for cars.

Eckhard

paragon
12-11-2004, 02:06 PM
Yes Roland, you must be lucky with your 2215 woofers !!

Eckhard ;) :p :D

pangea
12-11-2004, 02:10 PM
OK, I didn't know they're that closely related. :thmbsup:

Could you please explain "MTM" to me?

I have been thinking on and off, that I would like to build me some really scary speakers, though I haven't been able to decide which way to go.

Sometimes I'm leaning towards something resembling a pair of 4350. Then I'm thinking I should go for the large horns, i.e. 4530's, 4520's, U shaped 1/4 wave 30Hz DIY horn's, or even a pair of Jensen Imperial.

I do have a few alternatives to choose from:
2220A, 2215H, 2225H, 2123H, 2110A, 2441, 2445J and a few 075's
I would also be able to go digitally active, since I've got one Behringer UltraCurve EQ2496, two UltraDrive DCX2496 and enough amps to give each driver it's own amp with enough power to make them all sing.

I was also thinking of building a pair of Edgar 350Hz Tractrix horns even, but I'm still open to any suggestions you might have.

BR
Roland

EDIT: Hmmm...:hmm: Does this also mean the 2215H would work in a large horn?

paragon
12-11-2004, 02:11 PM
Yeahh, build one of the big horns. An old "Disco" version with the 4520, 2123, 2441 and 075 and drive them active !!

Eckhard

Earl K
12-11-2004, 02:15 PM
Hi Roland,

- Here's a picture of a TAD (studio-monitor) MTM setup .
- Additionally; here's apic showing "MTM" theory .

<. Earl K

paragon
12-11-2004, 02:26 PM
Roland, i will sim the 2215 with "AJ-Horn" in a 4530 and 4520 compared to the old 2205A.
Answer and pics tomorrow.

Eckhard

pangea
12-11-2004, 02:26 PM
-Eckhard

AHA, I thought however, it wouldn't work, having a 15" and a 10" in the same horn. Something having to do with different speed and different loading characteristic's or something like that. :confused:

-Earl K

Looking forward to your picture.


BR
Roland

pangea
12-11-2004, 02:45 PM
-Earl K

WOW, that looks awsome! Is that som kind of Dipole arrangement or some straight vented bass-bins?

EDIT: Are the bassdrivers identical and do you think it would work, using a Tractrix-horn slightly offset between the bass-drivers?

-Eckhard

Tanks, for making the sim, but what's an "AJ-Horn"?
Wasn't the 2220A also intended for the 4530 at the beginning?

Would it work to have one 2215H and one 2220A in the same 4520 horn, taking care of different octaves? Or perhaps putting the 2123H next to the 2215H?
It got me thinking, since I've seen pictures of the Jensen Imperial with different drivers in each cab, though I never understood the point of doing so. Perhaps someone could explain it to me?

Also what F0 could I expect?

BR
Roland

Earl K
12-11-2004, 02:59 PM
,,, straight vented bass-bins

- They're "vented" .
- Here's a couple more MTM projects. Ones' vented / the other sealed . Both use TAD components.

Earl K

pangea
12-11-2004, 03:30 PM
CHEEEESUS! They more look like works of art than loudspeakers and the VERY expensive kind at that!:D

What about plans for any of these babies? Anything readily available somewhere?

Do you think they would be able to match the power of a pair of 4520 with 2215H, 2123H, 2441/Tractrix or Selenium, 075, active digitally driven?

BR
Roland

Earl K
12-11-2004, 05:21 PM
Roland,

What about plans for any of these babies?

uh-uh, - no plans are currently available.

These are " State of the Art " setups , and as such ( IMHO ) it's unreasonable to expect plans to be commonplace on the web . But really , the know-how is available to just about anyone who wants to pursue this setup .


Anything readily available somewhere?

No, but,,, because "Project May" is in the midst of developing an MTM project for Don McR. ( our webmaster ) - some plans 'might" eventually spring worth ,, ( donations to the site-welcome ) .


EDIT: Are the bassdrivers identical ,,,/

By far the most common implementation of the MTM concept is through the use of identical woofers. But - I know from experience it's not the only successful approach. I've been listening ( on my right channel ) to a le10a ( in the top box ) mated to a le14 in the bottom box. Both cover the same range up to the @ 750 hz crosover point . If you look up the specs. you'll find these two old drivers have about a 3db difference in effeciency - but lucky for me, they also have different enough impedance curves which helps them "mesh" quite nicely. Sounds strange - but it works ( my Selenium horn is in between the two boxes ). I've had this right channel setup - going solid for at least a year and a half. I know it works great and won't hesitate to suggest to someone to eventually try it out.
My point is; I know asymmetrical MTM setups can work .


and do you think it would work, using a Tractrix-horn slightly offset between the bass-drivers?

- I wouldn't think of "off-setting" the horn. It'll skew the imaging. The only reason to go to the hassle to buildup a MTM setup , is to enjoy "holographic-like" imaging. "Missaligning" the vertical axis of the 3 most significant transducers is "image-suicide" . I don't use tweeters - so I won't venture an opinion about offsetting any tweeter until I try it .

- Also, don't get too hungup on that (IMO) "over-hyped" word "tractrix". What these MTM systems need to "work" is to begin the "build" with a horn that has great "imaging" capabilities. I know your Selenium does - because I also use it. And it doesn't have a "tractrix" flare-termination.


Do you think they would be able to match the power of a pair of 4520 with 2215H, 2123H, 2441/Tractrix or Selenium, 075, active digitally driven?

No, MTM is more about finesse ( IME ) - what you've just mentoned is more about power, like a truck. To me, it's like comparing a fine car ( maybe a Jaguar or a BMW or Mercedes car of some sort ) to a Mercedes Truck .


Here are a couple more pics;

The first illustrates my point ( le10/le14 matchup) by showing a commercially available "asymmetrical" MTM setup, while the second pic is included, just to show-off JBLs' stunningly beautiful, K2 S9500. ( Niklas owns a pair of these )

regards <> Earl K

paragon
12-12-2004, 03:26 AM
4530 with 2205A (black) and 2215 (red)

paragon
12-12-2004, 03:28 AM
4520 with 2205A (black) and 2215 (red)

paragon
12-12-2004, 03:36 AM
Wow !!,

Great stereo i see, Earl. Accuphase and... tube amp. Very fine speakers.
Are those bass drivers LE 15B ?

Roland, as you can see there is no great difference between both drivers.
You may take your 2215 for the big horns.
I woen`t put different drivers in one horn, but you may try it.

Eckhard

paragon
12-12-2004, 03:47 AM
You can see how exact AJ-Horn works. Maximum horn loading is exactly at the points JBL described. There is minimum cone movement at 60 Hz (4530) and 42 Hz (4520). The comb filter effects will be smoothed in the room and you can not hear them.

Eckhard

pangea
12-12-2004, 03:54 AM
Roland,
[/b]

uh-uh, - no plans are currently available.

These are " State of the Art " setups , and as such ( IMHO ) it's unreasonable to expect plans to be commonplace on the web . But really , the know-how is available to just about anyone who wants to pursue this setup .

[/b]

No but,,, because "Project May" is in the midst of developing an MTM project for Don McR. ( our webmaster ) - some plans 'might" spring worth ,, eventually .



By far the most common implementation of the MTM concept is through the use of identical woofers. But - I know from experience it's not the only successful approach. I've been listening ( on my right channel ) to a le10a ( in the top box ) mated to a le14 in the bottom box. Both cover the same range up to the @ 750 hz crosover point . If you look up the specs. you'll find these two old drivers have about a 3db difference in effeciency - but lucky for me, they also have different enough impedance curves which helps them "mesh" quite nicely. Sounds strange - but it works ( my Selenium horn is in between the two boxes ). I've had this right channel setup - going solid for at least a year and a half. I know it works great and won't hesitate to suggest to someone to eventually try it out.
My point is; I know asymmetrical MTM setups can work .

[/b]

- I wouldn't think of "off-setting" the horn. It'll skew the imaging. The only reason to go to the hassle to buildup a MTM setup , is to enjoy "holographic-like" imaging. "Missaligning" the vertical axis of the 3 most significant transducers is "image-suicide" . I don't use tweeters - so I won't venture an opinion about offsetting the tweater .

- Also, don't get too hungup on the "hype"/word tractrix. What these MTM systems need to work is to start with a horn that has good imaging capabilities. I know your Selenium does - because I also use it. It's not a tractrix flare termination.

[/b]

No, MTM is more about finesse ( IME ) - what you've just mentoned is more about power, like a truck. To me, it's like comparing a fine car ( maybe a Jaguar or a BMW or Mercedes car of some sort ) to a Mercedes Truck .


Here are a couple more pics;

The first illustrates my point by showing a commercially available "asymmetrical" MTM setup, while the second pic is included to show-off JBLs' stunningly beautiful, K2 S9500. ( Niklas owns a pair of these )

regards <> Earl K
OK, Tanks for your answer, very interesting!
I will definetly keep my eyes open for any MTM plans.:D

Do you think the 2215H and the 2123H could work i an MTM setup, with the selenium in the middle and wouldn't it work to put the 075 just next to the Selenium?
BTW, are you sure the Selenium doesn't follow the Tractrix curve? I've put the F0 700Hz value in to the "Melhuish Tractrix calculator" and it roughly comes out very close To the Selenium horn.

Also, wouldn't it be better to build a Tractrix horn with a lower F0, perhaps 400Hz or 350Hz even?

Furthermore, are there different kinds of "holographic" imaging?

As you maybe have seen from my previously posted pictures and from my avatar, I have no alignment what so ever, in my set-up, but never the less I can acheive a very good holographic imaging and I would say that this is made possible, mainly by three factors:
The construction of the horn, the distanse between them and to the listener and last but not least, due to the work of my Behringer UltraDrives and the time-alignents and the phase corrections they perform.

I only have to move one of the Selenium horns a little bit to completely loose the imaging and for the musicians and singers go right back in to the speakers and being trapped there, so to speak.

I got your point about the truck and the fine cars, but wouldn't it be nice if the fine cars could have the power of a truck as well?:D

BR
Roland

pangea
12-12-2004, 04:31 AM
Vielen Dank Eckhard!!!

The more I get to know about the 2215H, the more in love I become with it!

It seems very difficult to chose which way to go. I'll probably end up going both way's. :D

In that case I will probably have to to use the 2215 in the MTM-setup and the 2220A in the 4530/4520 configuration, since if Im not mistaken the 2220 as initially intended for the 4530.

Tuff choices we sometimes have to deal with.:D

Earl K
12-12-2004, 05:06 AM
Roland,

Do you think the 2215H and the 2123H could work i an MTM setup, with the selenium in the middle and wouldn't it work to put the 075 just next to the Selenium?

No ,the 2123h doesn't have enough Xmax to work in tandem with a 2215h - unless overall listening level is really restricted. Maybe a 2012h because it has the same Xmax of the 2225h woofer. Efficiency / sensitivity-curves for both of these 10 inchers, make a match "unlikely" . But, as I'm wont to say ; " buildup some test boxes and try/test it out " . Ya never know because of some other overlooked factor .


BTW, are you sure the Selenium doesn't follow the Tractrix curve? I've put the F0 700Hz value in to the "Melhuish Tractrix calculator" and it roughly comes out very close To the Selenium horn.

SSSHhhhh ; don't tell everybody - the price will skyrocket :D

Seriously, no , it's not a tractrix because of the way the horn flare abruptly "terminates" - but up to that termination , the "flare rate" or "M" constant is very, very close .


Also, wouldn't it be better to build a Tractrix horn with a lower F0, perhaps 400Hz or 350Hz even? Maybe, but I have yet to hear anything detrimental, when using this horn right down to its' rated flare cutoff .


due to the work of my Behringer UltraDrives and the time-alignents and the phase corrections they perform. Well, "time-alignments" or at least accurate "phase-alignments" will make a lot of difference in this area of "imaging" .

regards <> Earl K

Earl K
12-12-2004, 05:12 AM
Eckhard,


Are those bass drivers LE 15B ?

No, I'm quite sure the owner posted that they were a TAD woofer ( 1601a ??? ) .
Certainly from the front there's a strong resemblance between the two since both speakers use pleated-linen surrounds and have a very similar looking, "ribbed" cone.

<. Earl K

paragon
12-12-2004, 10:12 AM
Thanks Earl,
Thought it was your stereo.
Roland, the 2220 is a very high efficient driver and of course you may take them for the 4530/4520.

Eckhard

pangea
12-12-2004, 10:42 AM
-Earl K

Do you think it could work with (2215/2123) , apart from the limitation issue?

It's no problem to limit the 2123H with the Behringer UltraDrive. Besides, I never play that loud any way. 1W is more than enough to annoy my nabors. :D

What other kind of problems can you foresee with an asymetric (2215/2123) offset or having the 075 next beside to the horn mouth?

Right now I've set the x-over point at 690Hz 48dB/oct Butterworth, but I've been testing down to 650Hz without too much coloration.

BR
Roland

Earl K
12-12-2004, 11:23 AM
Hi Roland,


Do you think it could work with (2215/2123) , apart from the limitation issue? ,,,,,,,It's no problem to limit the 2123H with the Behringer UltraDrive. Besides, I never play that loud any way. 1W is more than enough to annoy my nabors.

In all seriousness, perhaps you need to make a system that has ( to begin with ) 2 boxes ( per side ) .

Bottom box ; 5 to 6 cu' ( @ 142 - 170 litres ) for the 2215H and a 3way tower (top-box ) that houses the rest. This would represent your own interpretation of a JBL 4344mkII ( but bi/triamped ).

By paying attention to esthetics and other the design details ,( all the while looking to the future ) , you'll get something immediately useful without having to "look" for components on eBay ( and all that hassle and expense ) .

I look to the "Performance Series" to illustrate" what I'm thinking here.

Here are some pictures ;

Using your imagination ( and scaling upwards ) ; :yes:
(a) replace the 8" titanium woofer with your 2123H
(b) replace the 4" titinium mid with your Selenium horn
(c) replace the 1" titanium tweeter with your silver ? 2402s
And you have your new " Tower of Power "

- So; to explore MTM with your 2123H - you simple "flip" your "ToP" and redo the Behringer Settings . :rockon1:

regards <. Earl K :cheers:

PS ; at some point, your going to have to discover the extra "bass- satisfaction" - that an extra 50 grams of "cone-weight / mms " will give .

Alex Lancaster
12-12-2004, 11:26 AM
:) It´s really interesting that 2 very different drivers come so close; It would be also of interest to check out 2226 and 7´s, because of their much higher power rating.

Earl K
12-12-2004, 11:38 AM
Alex;

It´s really interesting that 2 very different drivers come so close;

- Which 2 ( different ) drivers are you referring to ? ( This is a long thread )



It would be also of interest to check out 2226 and 7´s, because of their much higher power rating.

- What do you mean by "check out" ? In what ?

- In an MTM or in a 43XX setup or a 4530 or a 4520 or what I just suggested ? ( Again, this is a long thread )

regards <> Earl K :spin:

Alex Lancaster
12-12-2004, 11:57 AM
:) Earl: Yeah, sorry, it sure is long; I meant the 2205´s and 2215´s in the 4520/30 horns, the drivers are as different as could be, suspension, sealed vs vented back, gap depth, even power handling.

The 2226/7´s in the same horns, with enough power would be possibly 6 dB or more louder, but I wonder what the response curve would look like.

Thanks, Alex.

Earl K
12-12-2004, 12:07 PM
Alex;


The 2226/7´s in the same horns,

- Right,,, yeh, I'd especially like to check out the 2227 in a 4530/20.

... But then those woofers are as scarce as hens-teeth. :hyp:

- It's actually a lot easier to find K145s or E145s - which would do as well or better ( in a home hifi setting where power handling isn't the issue ) .

<> Earl K :D

Don McRitchie
12-12-2004, 12:08 PM
sealed vs vented backOff on a bit of a tangent. There is a popular misconception that the LE15A/B, 2215, 2216 and K145 are not vented. They are, but through the coil former and not the magnet structure.

Alex Lancaster
12-12-2004, 01:19 PM
:) Don: Yes, but acoustically, I would think the lack of a vent on the rear would make for a more damped speaker, ???.

Don McRitchie
12-12-2004, 01:59 PM
Possibly. The vent area of the coil former holes appears to be similar to the area of the back vents used in most other JBL drivers from that vintage. The critical issue is the permeability of the spider through which the airflow must pass. I have no idea how much of a restriction this presents.

davp2000
12-12-2004, 03:52 PM
Just bought a K 145 on Ebay. Price was 145 USD including shipping. Sorry, lost the other one (was to late), so i get only one :mad:
What do you think about this speaker ?
I think it`s one of the best you can get from JBL (similar to 150C, underhang voice coil, large alnico, rare).

Eckhard
The K-145 is a musical instrument loadspeaker. It does have a wide coild and a deep gap. However it is a rather ineffcient loadspeaker compared to other that JBL makes. It's main use was in custom bass guitar boxes and as a replacement for the bass speaker in a Leslie organ unit. The four ohm unit performs better than the 8 ohm unit. No my favorite JBL 15".

davp2000

pangea
12-12-2004, 04:14 PM
-Earl K

Is this in the region of what you were thinking?
http://img.photobucket.com/albums/v421/pangea2012/MTM.jpg

If so, would then the next step be, to determine the distance between the drivers and the x-over points?

BR
Roland

Earl K
12-12-2004, 04:33 PM
Hey Roland

Nice Concept! That's very handsome ! :yes: ( I love the lines )

Keep your working concept; ( & try to incorporate the following )

(i) Horn Height - center of the Selenium needs to be at ear level for your favourite listening position. Usually, 30" to 36" ( @ 762 - 915 mm ) depending on the chair/couch . ( this ends up making the height of the bottom box very important )

(ii) Get the 2 woofers edges ( in your case the 2215 and 2123 ) as close as possible to the "edge" of the horn - they don't need to touch. Once you've done this , tell me the distance between the centers of the two woofers .
Also measure the distance from the floor up to the center of the 15" woofer.

(iii)Optional : If you desire, sneek that 2402 between the Selenium and the 2123 ( as tight as possible ) - and tell me the new measurements between the woofer centers .

regards <. Earl K :cheers:

pangea
12-12-2004, 05:53 PM
Hey Roland

Nice Concept! That's very handsome ! :yes: ( I love the lines )

Keep your working concept; ( & try to incorporate the following )

(i) Horn Height - center of the Selenium needs to be at ear level for your favourite listening position. Usually, 30" to 36" ( @ 762 - 915 mm ) depending on the chair/couch . ( this ends up making the height of the bottom box very important )

(ii) Get the 2 woofers edges ( in your case the 2215 and 2123 ) as close as possible to the "edge" of the horn - they don't need to touch. Once you've done this , tell me the distance between the centers of the two woofers .
Also measure the distance from the floor up to the center of the 15" woofer.

(iii)Optional : If you desire, sneek that 2402 between the Selenium and the 2123 ( as tight as possible ) - and tell me the new measurements between the woofer centers .

regards <. Earl K :cheers:

Like this?

http://img.photobucket.com/albums/v421/pangea2012/MTM2kopiera.jpg
BR
Roland

Earl K
12-12-2004, 06:26 PM
Hi Roland

Looking Good - Real Good ! :rockon1:

Lets pick this up tomorrow - sometime . The "075" needs a better placement for both orientations.

Remember to make a drawing where the top box is "flipped" into the "normal" "orientation" - of a 43XX type playback system.

- ( 43XX systems have had in the past - the tweeter "beside" the horn / without the world coming to an "end" )

regards <. Earl K :thmbsup:

pangea
12-12-2004, 07:04 PM
Hi Roland

Looking Good - Real Good ! :rockon1:

Lets pick this up tomorrow - sometime . The "075" needs a better placement for both orientations.

Remember to make a drawing where the top box is "flipped" into the "normal" "orientation" - of a 43XX type playback system.

- ( 43XX systems have had in the past - the tweeter "beside" the horn / without the world coming to an "end" )

regards <. Earl K :thmbsup:I'm not sure I got it right this time, but just had to keep going, though t's way past bedtime here.:D

Right speaker

http://img.photobucket.com/albums/v421/pangea2012/MTM3.jpg

BR
Roland

Now I REALLY have to get some sleep.

pangea
12-13-2004, 07:47 AM
It just hit me, I've been posting stuff here, which has wandered off from the initial discussion about the K145 and now has very little to do with the intended topic.
Sorry about that.:slink:

Perhaps I should start a new thread with this MTM project.

BR
Roland

Earl K
12-13-2004, 07:57 AM
Hi Roland


Perhaps I should start a new thread with this MTM project.

You could do a "search" for all the older MTM threads and then move yesterdays posts over to the most appropriate one . As soon as you post to the old thread, it reactivates and pops to the top of the cue ( but you knew that ).

- As of this Wednesday ( the 15th ) I'll be "off-line" till 2005, meaning you might want to put this on the back-burner for a while if you want my input .

<. Earl K

pangea
12-13-2004, 08:04 AM
Hi Roland



You could do a "search" for all the older MTM threads and then move yesterdays posts over to the most appropriate one . As soon as you post to the old thread, it reactivates and pops to the top of the cue ( but you knew that ).

- As of this Wednesday ( the 15th ) I'll be "off-line" till 2005, meaning you might want to put this on the back-burner for a while if you want my input .

<. Earl KVery sorry to hear that you'll e away for so long. So before you go, perhaps you could have a quick look at my additions since yesterday?

http://img.photobucket.com/albums/v421/pangea2012/MTM4.jpg

BR
Roland

EDIT:
I was thinking that maybe the sub-chamber could be vented for extra bass extension and then I was thinking, it will be important to have both woofers very thorougly time-aligned, since they, from what I have guessed, will be paralleled together and crossed-over and driven by the same amp.

Is the assumption correct?

Earl K
12-13-2004, 08:17 AM
Sharp !

- The 2123h will perform best in a sealed box crossed at @ 300hz when in 43XX mode ( you can keep the ports - but make some provision to block them up )

- Keep the center of the Selenium - centered to the the 2 woofer cones . Move the 075 around - but not the Selenium .

- Make a drawing that has the 075 "under" the Selenium ( it could tilt up a bit so its aimed to some imaginary meeting point ). This drawing will be like your first drawing. But this time ( compared to #1 ) keep the 2 woofers centers symetrically arranged ( equal distance ) from the center of the Selenium . I know this will push the "2215h" down a bit and the 2123h up a bit. When they are arranged get the new measurement and comapre to 34" ( 863 mm ).

<> Earl K

pangea
12-13-2004, 08:25 AM
Sharp !

- The 2123h will perform best in a sealed box crossed at @ 300hz when in 43XX mode ( you can keep the ports - but make some provision to block them up )

- Keep the center of the Selenium - centered to the the 2 woofer cones . Move the 075 around - but not the Selenium .

- Make a drawing that has the 075 "under" the Selenium ( it could tilt up a bit so its aimed to some imaginary meeting point ). This drawing will be like your first drawing. But this time ( compared to #1 ) keep the 2 woofers centers symetrically arranged ( equal distance ) from the center of the Selenium . I know this will push the "2215h" down a bit and the 2123h up a bit. When they are arranged get the new measurement and comapre to 34" ( 863 mm ).

<> Earl KOK, would the " 34" ( 863 mm ). " be the ideal distance (center to center) between the woofers? And, which cross-over point would this relate to, if at all it does that?

Does the 075 have to be beneath the Selenium? If it's possible I would prefer to have it above like this.

http://img.photobucket.com/albums/v421/pangea2012/MTM5.jpg


Otherwise the tower would be even taller in the end.

BR
Roland

Earl K
12-13-2004, 09:36 AM
OK, would the " 34" ( 863 mm ). " be the ideal distance (center to center) between the woofers?

No, a 863 mm spread is the absolute maximum distance for any "hope" of the MTM mode to work with a 700-800 hz crossover point. Closer is better - but symmetry ( equal distance ) must be maintained from center of horn, to center of "each" woofer . As an example ; 400mm ( 15.75" ) from the Selenium center to the center of each woofer looks workable . The latest drawing with the 075 over the horn just needs to be tightened-up as much as possible.


Does the 075 have to be beneath the Selenium? If it's possible I would prefer to have it above like this.
- Sure, put the 075 over top of the horn - if you are never going to flip the top box over to a more "normal" 43XX orientation . I suggested "under" the Selenium" because my thought was for you to mostly use this setup "flipped" back into a more normal 43XX 4-way mode - then the 075 is in the correct postion of being ontop. I can see from your designs that you are not thinkng about flipping the top box ( "end over end" / "bottom for top, etc.") for the 2 different orientations ( or modes as I call them ) .


And, which cross-over point would this relate to, if at all it does that? In the MTM mode; 800hz for both the 2215 and the 2123, crossing over to the Selenium . You'll need to pad down the 2123 to match the lower output of the 2215. In 43XX mode ; 2215 to 2123 ( @340hz ), 2123 to Selenium ( @ 750 hz ), Selenium/2441 to 075 ( your choice ) .

regards <> Earl K

pangea
12-13-2004, 10:31 AM
No, a 863 mm spread is the absolute maximum distance for any "hope" of the MTM mode to work with a 700-800 hz crossover point. Closer is better - but symmetry ( equal distance ) must be maintained from center of horn, to center of "each" woofer . As an example ; 400mm ( 15.75" ) from the Selenium center to the center of each woofer looks workable . The latest drawing with the 075 over the horn just needs to be tightened-up as much as possible.


- Sure, put the 075 over top of the horn - if you are never going to flip the top box over to a more "normal" 43XX orientation . I suggested "under" the Selenium" because my thought was for you to mostly use this setup "flipped" back into a more normal 43XX 4-way mode . I can see from your designs that you are not thinkng about flipping the top box back & forth for different orientations ( or modes as I call them ) .

In the MTM mode; 800hz for both the 2215 and the 2123, crossing over to the Selenium . You'll need to pad down the 2123 to match the lower output of the 2215. In 43XX mode ; 2215 to 2123 ( @340hz ), 2123 to Selenium ( @ 750 hz ), Selenium/2441 to 075 ( your choice ) .

regards <> Earl K
No, actually I hadn't thought of flipping the top-box over, since I didn't think it could improve anything. Or could it?

Pading the 2123 isn't necessary since the Ultradrive easily can handle any level differences, unless it is required by the MTM principle. BTW what does it mean, MTM?

Why would you chose 800Hz in MTM mode? Is that better than say 700Hz?
Wouldn't it be possible to put the woofers a bit closer to each other at 700Hz? Or does the distance increase?

The Selenium does work great even at 690Hz.
What would then be the ideal distance between center-Selenium and center-woofer at 700Hz and at 800Hz?

The 075, I think, somewhere between 7-8kHz, would do it.

What I think will be an issue, is the difference in depth between the 2215 and the 2123, which probably will take some measuring with the UltraDrive to find out how much deeper the 2123 has to go in to the baffle and or maybe how much the 2215 will have to be elevated.
Time alignment between the rest however, is no problem for the UltraDrive. Or am I thinking wrong here?

http://img.photobucket.com/albums/v421/pangea2012/MTM6.jpg

BR
Roland

Earl K
12-13-2004, 10:58 AM
Hi Roland


No, actually I hadn't thought of flipping the top-box over, since I didn't think it could improve anything. Or could it?

I need to emphasize :

Primarily: You need to design from the perspective of making a workable rock-solid, 43XX system. That "usually" means keeping the 10" close to the 15". Therefore following that custom: You should have "flippable" top boxes to accomodate the 43XX mode ( or right way-up ) and the MTM mode ( or "upside" down ) .

Secondarily: So that you can successfully "explore" MTM stuff, make sure to follow the MTM design guidelines that I've mentioned ; symmetry, distances of horn to woofer centers, distance between woofer centers, alignments of center axis, etc.,

Conclusion : the top box that comes closest to full-filling both criteria, is the second one you made ( with the 075 between the horn and the 2123 ). That's in post # 79 . Again , the 075 could stay right there or move off-center . Give the "working" placement of the 075 - the best positon for a 43XX setup. Tweeters in my MTM setups - IME - are just a waste of investment and I turn them off. They destroy imaging ( more than enhance ) - but since you can time align it you shouldn't have the same problems I get .

Crossover Point for MTM : 800 hz is just an arbitrary point ( as high as you'll want because lower is better ) - if 700 works well for you, then use it. The secret is to get a 12db "acoustic" rolloff" from the horn blending with a 18db "acoustic" slope from the woofers. I do use the word "acoustic" not electronic . So , some RTA measurements are handy things to do .

<. Earl K :rockon1:

PS; MTM = Mid , Tweeter , Mid

paragon
12-13-2004, 12:45 PM
That was my question for today Earl, Don and others. Why is there no air vent in the back of K145 (2215, LE15) ? You answered.
Let`s see how other drivers work in the 4520/4530.
Wait.

Eckhard

paragon
12-13-2004, 12:56 PM
4530 with 2205 (black), 2215 (red), E145 (green)

Earl K
12-13-2004, 01:02 PM
Eckhard ,


You answered. Yep, Don reads minds .

My lame attempt to get some help for an ongoing le15b "problem" hasn't worked out.


Let`s see how other drivers work in the 4520/4530.

Nice graphs ! Are you going to start searching out E145s ? :D

<. Earl K

paragon
12-13-2004, 01:08 PM
No, the datas where just available to sim.
Do you want sim the LE 15B ??
Need Rdc, Qms, Qes, Vas, Xmax, ...

Eckhard

Earl K
12-13-2004, 01:08 PM
Roland,

Take a look at this new picture for some more "arrangement" inspiration .


It essentially "proves" / suggests that my articulated "concerns" about permanently placing the mid-driver over top of the horn driver are very much "overblown" .

This picture belongs to a member of this forum .

The speaker pic belongs to "pantaNS", and is from in this thread (http://audioheritage.csdco.com/vbulletin/showthread.php?t=1664) .

<. Earl K

EDIT
From reading the thread - the woofer is a 2245h , the mid is a 2206h and the rest is pretty obvious. The owner liked it so much he was going to build 4 more ( if I read correctly ). The crossover was passive with no mention of points or any mention of deliberate frequency overlap between the 18" and 12" ( which is what I would try ) .

While Operating in 43XX mode :
- This concept of some form of overlap within the 4-way crossovers' slopes ( between bass and mids ) is something I believe you can do with your Behringer. This will help provide some sonic "glue" for the split between the 2215 and the 2123 . You'll need to experiment some to find the best combination .
For example ; the 2215h lowpass could be set for around 340 hz, while the 2123H hipass might be set around for 120hz ( you will need to port/tune) the 2123 to add a bit of midbass extension. I'd mix and match slopes , like 12db for the 2215 lowpass and 6db for the 2123 hipass .

Just some more ideas :spin: :cheers: :spin:

And For Comparison ;( the other "all-cone", asymmetric MTM setup, that I had previously posted )

Earl K
12-13-2004, 01:20 PM
Eckhard,

Do you want sim the LE 15B ??
- Need Rdc, Qms, Qes, Vas, Xmax, ...

- It would be nice, but the Ts parameters for the le15b/2216 aren't available ( apparently ) .

< Earl K

pangea
12-13-2004, 03:39 PM
Roland,

Take a look at this new picture for some more "arrangement" inspiration .


It essentially "proves" / suggests that my concerns about permanently placing the mid-driver over top of the horn driver are very much "overblown" .

This picture belongs to a member of this forum .

The speaker pic belongs to "pantaNS", and is from in this thread (http://audioheritage.csdco.com/vbulletin/showthread.php?t=1664) .

<. Earl K

EDIT
From reading the thread - the woofer is a 2245h , the mid is a 2206h and the rest is pretty obvious. The owner liked it so much he was going to build 4 more ( if I read correctly ). The crossover was passive with no mention of points or any mention of deliberate frequency overlap between the 18" and 12" ( which is what I would try ) .

While Operating in 43XX mode :
- This concept of some form of overlap within the 4-way crossovers' slopes ( between bass and mids ) is something I believe you can do with your Behringer. This will help provide some sonic "glue" for the split between the 2215 and the 2123 . You'll need to experiment some to find the best combination .
For example ; the 2215h lowpass could be set for around 340 hz, while the 2123H hipass might be set around for 120hz ( you will need to port/tune) the 2123 to add a bit of midbass extension. I'd mix and match slopes , like 12db for the 2215 lowpass and 6db for the 2123 hipass .

Just some more ideas :spin: :cheers: :spin:

And For Comparison ;( the other "all-cone", asymmetric MTM setup, that I previously posted )Great, you should try reading minds! You've just answered most of my next questions! :D
But wouldn't that be almost the same thing as paralleling the 2123/2215 and simply designating an LP 700Hz third or fourth order characteristic to them, since the accoustical roll off would be there anyway???

EDIT:
As I was looking at the picture of the "pantaNS", I noticed the distance between the woofers and the mids doesn't seem to be symmetrical.

Also my current set-up manages to create a holographic image, without even having something above the mids.

So, it has to be very forgiving.

I've also tried to follow your suggestions the best I could and came up with this:

EDIT: Picture eleted. See posting 103.

-Eckhard
Is it possible to get rid of that big "dip" between 150 - 200Hz, with EQ or something and doesn't it affect the sound negatively?

Other than that it seems many different woofers can be used, with almost identical curves. My guess is that even the 2220 and the 2225 would produce similar curves.

You don't happen to have measured and compared the 4530/4520 to the Jensen Imperial, Klipsch or the LaScala? I wonder if any of those also have this dip.

BR
Roland

Earl K
12-13-2004, 04:12 PM
Roland :


But wouldn't that be almost the same thing as paralleling the 2123/2215 and simply designating an LP 700Hz third or fourth order characteristic to them, since the accoustical roll off would be there anyway???

Close, but not really. "Almost" is a big word here. More important, the level of the 2123 needs to be balanced to that of the 2215. Its the combination of "level", low pass and hipass slopes, that will really fie-tune this "Quasi-MTM design. There will be some experimentation ( by you ) in this area - its' agood thing you have that Behringer .

Truthfully, since your multiamping with an extremely variable, DSP based crossover, it'll take a bunch of fiddling around "later" to find the best points and slopes to make this design work. I will say; the more a person "splits" these sources far apart - IME - the "shallower" the slopes should become to compensate for the split .

But this can all be left ot next year - if you prodeed and build something like this up .



I've also tried to follow your suggestions and came up with this:

I see that,,, :thmbsup:

- the 35cm radius looks good , from horn to each woofer center
- since the total 70 cm spread leaves some extra room between the 2123 and the horn , I think the 075 should go there, back "inline" with everything else .
- I don't see that any other changes are necessary .
- The way the design is right now means it does not need to be "flippable" ( like I was pushing for, to mantain the traditional 43XX character ) - therefore you can still incorporate that "groovy" tapered top-box "look" you had previously - :yes: if you want .



:cheers: Earl K

EDIT #1:

the "pantaNS", I noticed the distance between the woofers and the mids doesn't seem to be symmetrical.

The pantaNS design is "assumed by me" to be more of a typical 43XX, 4way design, but with a "flipped midrange" , so distance-symmetry of "woofers to horn center" isn't a primary concern - unless his design is actually a "quasi" MTM ( which is what your design really is ) . So, maybe you should email him ( if possible ) to ask for some crossover insights .

EDIT #2:

Also my current set-up manages to create a holographic image, without even having something above the mids.
So, it has to be very forgiving.

Yes, actually your horn is your "trump" card here. It already has such strong "imaging" that everything you do is for "enhancement or deepening" of the effect . It's a great foundation to be starting from .

paragon
12-14-2004, 07:44 AM
Roland, this are my 4530 with 2205 drivers in my little 3x3m room.
Measured wit HiFish-AC.

Earl K
12-14-2004, 08:00 AM
:D - Good Looking Curve .

Yep, I'd definately enjoy my music played back through that !

Plus, a very nice round "thump" factor from that horn. :yes:

:cheers: <>Earl K

pangea
12-14-2004, 09:34 AM
-Eckhard

That curve looks fabulous! What happened to the dip at 150Hz? Where did it go?

-Earl K

Thanks again for all your invaluable input!
I've tried to mail to "pantaNS", don't know yet if I'll get a reply.
Now I'll have to make the plans and calculate the volumes and ports and stuff and pay the lumber yard a visit in the near future.

In the "final" drawing I've added some (almost) JBL blue even. :D

:happyh:

EDIT: Picture eleted. See posting 103.

Cheers :cheers: :)

paragon
12-14-2004, 09:50 AM
Roland, that`s the difference between measurement in a living room and simulation or measurement in a very good acoustical damped room (Can´t explain, sorry). AJ-Horn can not sim a room (Cara can). There is only an option where the speaker stands ( Free, Wall, Wall and ground, Edge).
As i said, you doen`t hear the comb filter effects and there is always other sound in different rooms. Sound of the 4530 is different in my living room (4,5 x 6,5m). The bigger 4520 will go down to 40 Hz (Edge).:D
By the way (of topic) very fine speaker you try to build.

Eckhard

Earl K
12-14-2004, 10:14 AM
NICE !

- I particularly like the horizontal "oak" grain of the wood. That along with the diagonal line gives the bottom box an very strong "nod" to the "stylings" of the L300. The sloped baffle look of the L300 has always attracted me. :yes:

- Glad to be involved . :thmbsup: Don't be too surprised if I buildup a version of your design in the future. I have some 2123h mids and some Fostex 945 tweeters that need a system like this . :rockon1:

- Some final advice ( till the new year ); for this type of "ground-breaking" project - build test boxes before "committing to the final design " . It's entirely possible the 2 cone woofers may need to tighten in a little more, towards the horn - this will "only" be if you feel the midrange blend, is "weak" from 300 to 800hz .

- So, having a removable baffle in the front of the top "test boxes" would greatly help this process of discovery. Also the tweeter position could end up having to shift "off axis" - to the inside if this "tightening" happens .

:xmas:

:cheers: Earl K

pangea
12-14-2004, 11:29 AM
Hmmm, Perhaps I can "borrow" some test boxes to make the tests.

I don't have access to a work shop, so I'm forced to do almost everything in my kitchen.

On the other hand, if it's a real possibility that the woofers need to be closer to each other, then maybe I should try to do that right from the beginning. I think a few cm would be possible to take away, but then I won't be able to use the 2445J.

What would be the optimal distance from the Selenium, if there is such a thing, at, say, HP 700Hz/-48dB/oct Butterworth, or 750Hz/-24dB/oct Butterworth?

Just as I had posted my previous posting, I got an idea:



EDIT: I had also noticed the similarity to the L300! :D

EDIT2: I've cleaned up and deleted the earlier pictures, since they were full of flaws.
Instead I've added the final design and also added a few details. Hope you don't mind.

http://img.photobucket.com/albums/v421/pangea2012/MTMdesign.jpg

BR
Roland :D

Zilch
12-14-2004, 12:36 PM
What nifty drawing software are you using there?

pangea
12-14-2004, 01:12 PM
What nifty drawing software are you using there?
OK, are you ready? Hold on to your hat.

I'm using MS Powerpoint!:D

BR
Roland

Earl K
12-14-2004, 03:05 PM
Hi Roland


Hmmm, Perhaps I can "borrow" some test boxes to make the tests.
- I recommend that you "delay" constructing anything ( but test boxes ) until 2005 .



I don't have access to a work shop, so I'm forced to do almost everything in my kitchen.
- "That" will be a significant impediment to the ultimate success of this project .
- If you can only "muster" one buildup or "kick at the can", then its absolutely paramount that the front baffles of both the bottom & top boxes, be "removeable" for at least some form of "testing phase".


On the other hand, if it's a real possibility that the woofers need to be closer to each other, then maybe I should try to do that right from the beginning.

- That would be nice, but there are just too many variables, to get it right the first time out, on a "hybrid" project of this sort.
- If you want a bullet-proof project, then go "traditional". "Flip" the top box back to a normal orientation, with the 2123 over top of the 2215 and the horn over top of the 2123.


I think a few cm would be possible to take away, but then I won't be able to use the 2445J.
- Well, I thought you had some 2441s to use. They do have a smaller magnet which helps .


What would be the optimal distance from the Selenium, if there is such a thing, at, say, HP 700Hz/-48dB/oct Butterworth, or 750Hz/-24dB/oct Butterworth?

- The crossover slopes you keep mentioning, I feel , will be too steep for this sort of arrangement. If you are committed to these slopes - make a "tight-pack" of these components, arranged in a normal 43XX orientation .

- Again, ( for a hybrid MTM ) there is no optimal distance when one factors in the components you are committed to using. The spread distance to some degree will be dictated by the sonic "personality" that is created when the 2215 reaches up and shakes hands with the 2123 ( when operating in the MTM mode ). I anticipate the 300 hz to 600 hz area will be too pronounced. So, it's possible the woofer may need to physically "drop" down some - this is based on the fact that at it's present height ( which I don't remember ), "floor-bounce, ( from reflective floors" ) will cause about a 3 db deep / octave wide null "or dish-out" , centered at some frequency ( below 350 hz ). Because the 2123h is a "lightweight performer" below @ 300 hz, it just won't sufficiently fill in that null. A speaker with better "lowmid" performance would. Therefore something has to physically move, to pickup the slack and correct the situation. Finding the correct working "heights" and distances between the woofers is all about some sonic "deal-making" or compromising. Additionally, the "narrowness" of these boxes works against supporting bass and midbass frequencies. That also will work to enhance midrange. Putting a bigger spread between the woofers, will help break apart this midrange - but the spreading also starts to break apart any homogeneous blend. This is very much like "pushing" string on a table .

Conclusion:
- You either have to have test boxes to find out all this stuff or you need a system of "removeable baffles" to accomplish the same.

- I wish you hadn't deleted the other pictures because they had useful information in them.
- The remaining picture is now lacking all of the dimensioning lines, which I need for a reference .
:band: :tree: Earl K ( over, out and gone for the holidays )

pangea
12-14-2004, 04:49 PM
-Earl K!
Don't worry about the kitchen! I've got most of the tools needed to build almost what ever I fancy. It's only the nabors I worry about if I have to build a lot of test gear.

I haven’t figured out yet how to make the baffles removable tho, considering the chosen design (the sloping 45 degree corners).
But I'm confident I'll solve that and find a way. I'm usually quite creative.
I have a few boards I can use for test baffles, when I've figured out how to make the baffle removable.

You're right, I will use the 2441 drivers, I just thought that if for some reason I would want to test the 2445's, it just won’t be happening now, but that's OK.

Actually I prefer the 6 and 12 dB Bessel filter characteristic's, but it's just that with the Behringer UltraDrive it's been so much easier to use the steeper slopes, making it possible to set the x-over point lower for the Selenium horn.

Should the 300 to 600Hz area be to pronounced, it's no problem for the UltraDrive.
Also, the UltraCurve will detect any peaks and dips in the response, so I don't think that will pose any problems.

I've also put back the picture with the measurements.
If you would like any of the other pictures, I could easily mail them.

http://img.photobucket.com/albums/v421/pangea2012/MTMdesignspec.jpg

BTW, what's a "tight-pack"?

Take care.


BR
Roland

paragon
12-15-2004, 01:35 PM
Is it possible to get this four foam rings at the outer side of the basket as a spare part ?

Eckhard

pangea
12-31-2004, 06:29 PM
First of all I would like to wish everyone a HAPPY NEW YEAR, although the new year celebrations have been very somber here, since estimates say that more than 150 000 people have died in Asia, of which more than 3000 were Swedes.

None the less I have been occupied trying to learn some about my project.

I'm anxiously awaiting the return of Earl K and hoping the discussion will continue soon.http://audioheritage.org/vbulletin/images/smilies/smile.gif

-Earl K
In case you're back already, there have emerged a few questions during the holidays, which I would be grateful if you would like to address first.

You wrote:


While Operating in 43XX mode :
- This concept of some form of overlap within the 4-way crossovers' slopes ( between bass and mids ) is something I believe you can do with your Behringer. This will help provide some sonic "glue" for the split between the 2215 and the 2123 . You'll need to experiment some to find the best combination .
For example ; the 2215h lowpass could be set for around 340 hz, while the 2123H hipass might be set around for 120hz ( you will need to port/tune) the 2123 to add a bit of midbass extension. I'd mix and match slopes , like 12db for the 2215 lowpass and 6db for the 2123 hipass .
I’ve been thinking, perhaps I should try to make the boxes sealed. I’ve read that sealed boxes have a much better transient response, so I was thinking of using a large (D, 30cm*L, 15cm) cardboard duct, for the 2123’s. For the bass-bin I was thinking of making it possible to go both sealed (80L) and vented (163L), by plugging the holes in the internal bracing.
Do you think a bit of shelving EQ, on both woofers would be able to extend the frequency range somewhat, as well as making it possible to lower the output, so that they won’t be as pronounced in the 300 - 600Hz region, like you said and at the same time keep the sonic “glue” intact?
Any comments on this?
I have also read somewhere that a first order x-over on the bass and mid-bass (giving a 90 degree phase shift), should be complemented by an equally first order x-over, or a third order (90 or 270 degree phase shift) x-over on the midrange, giving a total of 180 or 360 degree, or a full turn, phase alignment, which would give a perfect summation.
In my case, using the 2441, I think a third order x-over would be better/safer with a x-over at 1000Hz. Wouldn't you agree?
Then the task of time-aligning the drivers, would be much easier for the Behringer UltraDrive, at least I think.
While you were away for the holiday’s, I’ve also been busy trying to figure out the best/ideal x-over point between the 2441 and the 2123 and all things considered I think that 1000Hz/34cm distance between driver-center, seems best in my view.
I’ve also come across a program called XDir, (http://www.tolvan.com/xdir/) which is supposed to calculate lobing-effects, though I’m not sure how it works, or how to find the best values. Perhaps you’re familiar with the program? http://www.tolvan.com/xdir/ .

BR
Roland

lfh
12-31-2004, 08:00 PM
I’ve also come across a program called XDir, (http://www.tolvan.com/xdir/) which is supposed to calculate lobing-effects, though I’m not sure how it works, or how to find the best values.

Hi Roland,

why don't you start a new thread about your speaker project (this subject interleaving gets confusing ;) )?

As to the program in question, I haven't used it (and I won't since I'm too lazy to fire up the Windows emulator...), but I have written such stuff (and I know who the author of this one is - you can remove the "supposed" part ;)). Judging from the sparse documentation on the site, he uses the simplest possible transducer model - point sources (i.e. omnidirectional ones) - in a vertical line array and adds the contributions at positions along a half circle in the vertical plane. The program also takes source level and the relative phase difference into account, so effects of different crossovers could be studied (provided that you calculate filter attenuations and phase angles by other means). I think this little program should be useful to help gaining a basic understanding of how two or more sources combine when they are close compared to the wave-length respective far apart relative the wave-length, but it's not really a design tool. (I can imagine he wrote it when teaching electroacoustics at KTH.)

pangea
01-01-2005, 06:12 AM
Hi Roland,

why don't you start a new thread about your speaker project (this subject interleaving gets confusing ;) )?

As to the program in question, I haven't used it (and I won't since I'm too lazy to fire up the Windows emulator...), but I have written such stuff (and I know who the author of this one is - you can remove the "supposed" part ;)). Judging from the sparse documentation on the site, he uses the simplest possible transducer model - point sources (i.e. omnidirectional ones) - in a vertical line array and adds the contributions at positions along a half circle in the vertical plane. The program also takes source level and the relative phase difference into account, so effects of different crossovers could be studied (provided that you calculate filter attenuations and phase angles by other means). I think this little program should be useful to help gaining a basic understanding of how two or more sources combine when they are close compared to the wave-length respective far apart relative the wave-length, but it's not really a design tool. (I can imagine he wrote it when teaching electroacoustics at KTH.)
You are absolutely right! I almost did start a new thread for this reason, just before christmas, but wanted to keep the discussion going for as long as possible.

So from now on, I'll continue to write about this in a new thread.

About "Xdir", I'm sorry I used the word "supposed". It wasn't my intention to be critical or anything of the program, it only meant that I didn't know how to use it correctly.
So perhaps I should have said, "it is said to"..., instead.
I'm sure the program is very good.

BR
Roland

lfh
01-01-2005, 06:47 AM
About "Xdir", I'm sorry I used the word "supposed". It wasn't my intention to be critical or anything of the program, it only meant that I didn't know how to use it correctly.
So perhaps I should have said, "it is said to"..., instead.
I'm sure the program is very good.

No worries, I just wanted to say that it most likely does what it's supposed to do (as opposed to some crappy freeware out there...). And yes, it should still be useful for your purposes. E.g. first look at the frequency range where the twin basses operate but the tweeter is silent (e.g. do one plot per octave) and then study what happens around the crossover frequency where all drivers contribute. Vary one parameter at a time (spacing/level diff/phase diff), and you'll get a good grasp of how the array works, and how the filter properties come into play. It should also be interesting to compare a conventional design and an MTM around the crossover frequeny.