Thanks for the Help

[alskinner]

This is my first post. Just wanted to say thanks to all the members for providing the information and enthusiasm for me to finally do something I have always wanted to do, that is to build a set of Hybrid JBL monitors. I would especially like to thank Ian, Mr. Widget, Griskard for the plans and information on the 4344/4345 monitors, 2397 smith horn and the other drivers. THe pictures( if I can load them right) are the end result. Again thanks to all for providing a forum where JBL nuts can gather.

Sincerly
alskinner

[4313B]

Very Cool! :cheers:

Please post a few more pictures. :yes:

[Mr. Widget]

Tell us more about your system, like which amp goes with each driver etc. I recognize the Threshold and Bose amps... what are the other two, and what are you using for a preamp?

Widget

[alskinner]

Well, I little about the system right now I am using an Ashly XR4001 for the crossover. The amp on top going to the 2235 bass is a Sunn SPL 9000, realy gives a tight controlled bass. The second amp down is a Thresold Stasis Two connected to the 2012 midbass. THe trusty old Bose 1801 is connected to the 2441 horns and the Audio Matiere Accordance EL34 tube amp is connected to the 076 tweeters, really provides an accurate high end with out being harsh. The speaker cabinets are 7.0 cf tuned to 32 hz. I know that is over the JBL recommended 5 cf but it sounds great.
As for the preamp I run either an Soundblaster AWE64 Gold, M-Audio Audiophile 2496 cards or a Soundcraftsmen DX3000 preamp. I also have a pair of L300s and a pair of Altec A7s.

[scott fitlin]

Those horns!!!!!!!!!! I like them, very much!

[Zilch]

OOoooooo, 076's! :cool:

[boputnam]

Originally posted by alskinner
I am using an Ashly XR4001 for the crossover. Congrats!! Nice work.

Tell us (er, me...) about the XR4001 - Widget and I are fans of their two-way, but haven't tried this. I've been hoping Ken Patchalphabet would get one...

[alskinner]

The Ashly XR4001 has performed superbly. Being able to dial in the exact crossover frequencies and adjust the filter curve greatly reduced the manhours finding the right values for a passive. The sound is dynamic and smooth unlike some of the other op-amp electronic crossovers on the market. I have most of the components to build a set of passives, but like the sound of the Ashly so much I have put off building them until later. The crossover is an excellent tool for building 4-way speaker as you can cut out individual drivers in order to track down problems. Of course the down side is having to get 4 ampsl to live in harmony without ground loops.

[Robh3606]

Very Nice speakers! Where did you get the Smith horns??

Rob:)

[speakerdave]

Nice work. I'll bet they sound really good.

I second the question about the Smith horns. Did you make them yourself?

I'd be interested in a detailed comparison of that cat's eye tweeter and the 077 in your L300's.


Originally posted by alskinner
The speaker cabinets are 7.0 cf tuned to 32 hz. I know that is over the JBL recommended 5 cf but it sounds great.

I'll bet that's one way of getting a cabinet without a big hunk in the bass response.

Thanks,

David

[alskinner]

The horns were built by Dean Labbe in Calgary Alberta Canada.
They are pure cherry and are duplicates of the Westlake Tatrix Flare horns. He also builds horns for a lot of the old Altec drivers.

As far as the box, increasing the cubic feet of the box caused a slight rise (about 1 decibel according to WINISD) in the 35 hz region. I am planning on retuning the box to 30hz which which will remove most of the hump. It also has the .5 cu ft subchamber for the 10" midbass. The box is heavily reinforced every 12 inches with 2X3 and 1X3 internal bracing and I used Dow Corning pink insulation on all sides except the front baffle. I did put a removable back panel on the back for access to the 076 driver and wire connections.

Although the differences between the 076 and 077 drivers are subtle the 076 IMO has a smoother dispersion and gels with the 2441s better. One of the things I test tweeters on is their ability to reproduce cymbals accurately. The 076 IMO does this better than the 077. Of course the drawback is finding the 076s (2403s)at a reasonable price.

[4313B]

I agree with you with respect to the 076 versus the 077. However, the 077 in your L300 is at a disadvantage if you A/B it against your Ashly driven 076. It's been said that for best performance the ring radiators should be crossed actively. They only require a few watts of high quality amplification to really shine.

[alskinner]

Thanks for the response. You are right about A/B comparison against the L300s. I have a spare set of 077s that I tried first in the new speakers and there is diffenately a difference between being actively and passively crossed.

[johnaec]

So how do you like the 2012H's? What crossover frequencies are you using?

John

[alskinner]

I really don't have anything to compare the 2012s to, but really like the response they IMO extremely accurate in the midbass frequencies. I orginally wanted to try the 2122 or 2123, but decided on the 2012 after doing research on the JBL site. I am very happy with the 2012. Right now I have the drivers crossed at 300Hz, 1K,and 10K.

[speakerdave]

I orginally wanted to try the 2122 or 2123, but decided on the 2012 after doing research on the JBL site. I am very happy with the 2012. [/B]

I wonder if you could tell us more about what they said that convinced you the 2012 was the way to go.

David

[alskinner]

Some of the reasons I chose the 2012Hs were:

Slightly better frequency range.
Published specs on 2nd and 3rd Harmonic distortion being <1%
Warranty, If I didn't like them I could send them back.
Deeper gap groove and greater xmax.
fs of the 2012 is at 61hz while the 2123 is at 85hz
I got these new and had I gotten either the 2122 or 2223 there was a good chance they would have to be reconed.

All I had to go on was specs since these were the first 10" drivers I have used in a speaker application. Although as we all know specs by JBL can be off the mark at times.

[Robh3606]

'All I had to go on was specs since these were the first 10" drivers I have used in a speaker application. Although as we all know specs by JBL can be off the mark at times.'

Yes they can I have run both 2122 and 2123 with active crossovers and without the tailoring done by JBL with their passive crossovers in the 800hz to 1.2 K range both drivers have a definite bump there. The 2123 is smoother but anyone looking at the 2123 FR plot on the data sheet is in for a surprise. Looks to me you have a one nice set up. Are you really going to go passive?? Just seems like lots of work if you are there now.

Rob:)

[alskinner]

I think you are rightn Rob, I am completely satisfied with the set up. Howeve in the future I would like to try 2 of the Dynaco Mark III amps I am modifing on the horns and maybe see what a set of TAD 4001s would sound like ( when I win the lottery). I'll save the passive components for the next project. I am a lucky guy in that my wife loves to help work on the cabinets.

[Ken Pachkowsky]

Very nice job. Am very impressed with the whole system. I see your quite fond of the Ashly 4001?

Thanks for the pics.

OK BO! I will get and try a 4001 on the Westlakes.

Those 076's are damned cool lookin. If I added a pair to mine and crossed over to them at 10k I could have a hybrid SM-1.

Hmmmm. What ya think BoBo!

Ken

[Mr. Widget]

Originally posted by Ken Pachkowsky

Those 076's are damned cool lookin. If I added a pair to mine and crossed over to them at 10k I could have a hybrid SM-1.





I would suggest you take the 2441s up to 10KHz lose the 2426s, and use either the 076 or 2405.

Covering more of the mids with a single driver will give you an even more coherent sound and I am pretty sure both the 076 and the 077/2405 have a better top end than the 2426.

Or..... you could sit back and enjoy the music and not worry about all of the possibilities out there.

Widget

[Ken Pachkowsky]

Originally posted by Mr. Widget

Or..... you could sit back and enjoy the music and not worry about all of the possibilities out there.

Widget

Hmmm. You may have something there Widgy!

I was only kidding, although I have thought about exactly what you suggested. I am sure there was a reason they did what they did. If it ain't broke....

Nice to hear from you!

Ken

[alskinner]

Thanks for the positive posts. This project has been challenging, frustrating and in the end worth it. I just wanted to post a little about myself and some thoughts on JBL and audio in general. MY first experiance with JBL was in 1975 while stationed in the service in Germany. I frequented a small discoteque in a nearby town (they played everything but disco). Anyway it had a pair or L200s, driven by a Bose 1801 amp, Phase Linear 2000 preamp and Thorens 124 turntables. I was immediately impressed with the dynamic and forward sound. I could not afford the L200, so settled for a set of L36 Decades (My ears still hurt). Upon leaving the service I went to college and got a degree in Electronics and, Radio and Television Repair. Unforunately, I have not used them much until recently. During this time I learned important lessons like; don't touch the ouput end of a 600v transformer with the power on and putting tinfoil around the fuse can cause smoke and a small fire. Time marched on and between marriage, mortgages and life in general the dream of owning a high end JBL system faded.

In 1999 I was introduced to e-bay (oh boy) and found a set of L300s and won them for $1100.00, but they were 800 miles away and I was afraid to have them shipped. So I went on the JBL site and got the dimensions of the speakers and measured and remeasured the rear of the old Buick and finally decided if I took the rear door off and the back seats out I could fit them in the car. So armed with wrenches, snacks and a buddy off we went. We arrived at Norfolk, Virginia, took off the door put the speakers in, reinstalled the door and drove home. The speakers were in excellent mechanical shape, although 2 years ago I had to recone the 136As. Still love the sound of the L300, but also wondered could there be anything better.

In 2003 my Army Reserve unit was mobilized and off we went to Iraq. Between listening for the sound of mortars whistling overhead and readjusting the TV satelite dish when the wind would blow it over I started thinking about the large JBLs again. I had in mind at the time to build a set of Olympus SR8 clones. so when I came back in May of this year I started researching the Olympus and got re-acquanted with this site. I had lurked around it for a couple of years but never registered. The more I researched the more I found that the Olympus wasn't going to provide the sound I was looking for and started turning my attention toward the 4343/4344/4345 monitors. When Ian Mackenzie published the plans for these monitors I was off.

The first thing was Ian's warning of "Oh and if you stray from the flock its at your own peril, this series will be about the authentic original designs, not mutants or hybrids". So I was apprehensive to start with, not having the expertise and experience of a lot of the members of the forum, but knew what I wanted to try to achieve. First I had to decide on the drivers. (To be continued in next post)

[alskinner]

I have always been fond of the 2 inch drivers and horns, especially the 2440/2441, even with their subharmonic distortions they are hard to beat when tamed properly. Concerned with Alnico magnet losses I found a set of 2441 NOS drivers and started building the system around them. I first tried the drivers on a set of 2355 horns on top of my Altec A7s and a N333 crossover with a 077 tweeter. Although the Altec has a deep boomy bass it did give me ideas on what the midrange would sound like. I quickly discovered that to use the 2355 horns I was going to need a room at least twice as big as I had although they did have an interesting and not bad sound. So after much research I settled on the Westlake style 2397 smith horn. The sound was exactly what I was looking for, still exremely dynamic, but smooth and focused. Now it was time to start on the cabinets.

I had to buy most of the tools in order to build the cabinets; a router, Jasper Jig, table saw. and miter saw. Following the general outlines of the plans on the 4344/4345, I decided to make the cabinets shorter and deeper since I wasn't going to need the space for the 1 inch horn driver. The cabinet ended up being approximately 7.0 cu ft even with the .5 cu ft chamber for the 10" midbass and I wondered was I going to be in acoustical trouble by exceeding the recomended 5.0 cu ft. As it turned out by tuning the cabinets to 32 hz the graph on WINISD showed only a slight hump in the 35hz region. After much internal debate I decided on the 2012H for the midbass. Here's were frustration stats kicking in. I orded these through US Speaker and eagerly awaited their arrival. When UPS delivered them one had a broke basket and the other had the anti-rattle cup over the magnet off.
However US Speaker did make them good immediately and sent another pair out the same day that arrived in excellent condition. So now it was time to get the 2235H bass drivers. I found a set on e-bay reputed to be in excellent condition, when they arrived and I hooked them up the cone lept out of the foam sorrounds and off to Orange County Speaker they went. When I got them back 3 weeks later, much to my dismay they had been reconed with 2225 surrounds. Again Orange County Speaker made it right with no problems just another 3 week wait. Meanwhile, I had to decide on a crossover. I knew building passives were going to be a pain in the butt since the 4345 crossovers would have to be modified for the 2441 and 2012, so as much as was sceptical about active crossovers I did reseach on Rane, Ashly and Marchand decided on the Ashly 4001, again I ordered this from ZZsounds and arrived promptly in good condition. Finally the 2235 arrive back and I am ready to test. I connect up the ashly to the 4 amps and immediatley have ground loop problems. After ground lifting the amps ( a dubious practice at best) I am ready to go. Out of the box the Ashly sounds ok but not what I expected, but then I start adjusting the filter slope curve and low and behold everythjing opens up and the sound is great. Also the attentuation for each driver is excellent fot the amps that don't have gain controls. Then two days later the Ashly simply stops working. I go through all the troubleshooting to no avail. I call ZZsounds and they immediately send another one that has been performing flawlessly for 2 months now. Good thing about the ashly it has a 5 year warranty. So now I have the speakers accoustically where I want them and order the cherry veneer. Low and behold when it arrives I have one half cherry and the other appears to be walnut, another week wait and the speakers are finally finished.

Anyway thanks for letting me rant and rave a little. As a lot of you all say the most important thing is to enjoy the music and remember it's only a hobby

AL

[Ken Pachkowsky]

L36's.....I had to settle for L26's in around the same time (74). Then went to 030's and 4350's.

Am going to get the Ashly and may call upon you for tuning advice.

Ken

[Ken Pachkowsky]

Funny, just jumped onto Ebay and there was one just posted for 275 BIN so I did.

Will be in touch.

Ken

[boputnam]

Originally posted by alskinner
I connect up the ashly to the 4 amps and immediatley have ground loop problems. After ground lifting the amps ( a dubious practice at best) I am ready to go. :shock:

Dood...

I don't know how exhaustively you've traced the GL (and know it can be horribly trying experience), but if I understand your solution, it is not a good one. :no:

You should work backward from the amps, unplugging things until you know for certain where the GL is originating.

But, until we know that - you are running unbalanced gear into the Ashly, and then it into the amps, right?. Your unbalanced gear is seeking ground through your balanced gear. I don't know your rack but are the amps balanced? If so, for the connections OUT of the Ashly to the amps, you should drop Pin1 at the amp inputs. Are your preamps balanced out? If so, do the same thing, dropping Pin1 at the Ashly inputs. If that doesn't solve the problem, you may need to isolate your single-ended gear by dropping the shields, but this may not work satisfactorily.

You could also stuff an isolation transformer between the pre amp and the Ashly. We've gone over this here: http://audioheritage.csdco.com/vbulletin/showthread.php?s=&threadid=171&highlight=connectivity
and here: http://audioheritage.csdco.com/vbulletin/showthread.php?s=&threadid=423&highlight=ground+loops

A worthy addition for either thread is the Radial JPC - it's pretty winkie. I use a number of their J48 and JDI in my PA gear (http://www.radialeng.com/), and they're wonderfully clean and uncolored. Either way, you should do whatever possible to reconnect those amps grounds.

As well, Rane makes a goofy thing called the BalanceBuddy, but I had -zero- luck with it - it did not isolate the grounds in my case. Could be my unique situation (I'd I sell you mine, if it worked for you).

[alskinner]

Thanks Rob

I can disconnect the pre-amp cables from the Ashly input and the troubles disappear. Dead quiet except for the normal amount of white noise in the horn drivers. the preamp is about 20 ft away as I normally use the sound cards in the computer when I am not doing critical listening. Every connection is unbalanced. The one thing I haven't tried is plugging the computer into the same power strip as the amps. THanks for the information, Of all the searches I did on the problem I somehow missed this one. You are absolutely correct not having the amps grounded properly presents a safety problem that I need to address sooner rather than later. Fortunately I don't have any kids and cut the amps off with the power strip when I am not around, but it is still a dangerous practice.

[alskinner]

Sorry Bo on the last post I called you Rob again thanks for the info.

[boputnam]

Originally posted by alskinner
I can disconnect the pre-amp cables from the Ashly input and the troubles disappear. Me, too. How are you coming out of the pre-amp? I'm guessing it's unbalanced - RCA type. I've tried thousands (OK, that's an exaggeration...) of options, and RCA - TS into the EQ works best. Whenever I try to go balanced into the EQ, I enable a ground path to the rack.

Try either a RCA - TS patch cord, or if that doesn't isolate the problem, get one of the isolation transformers we've talked about. Even the Radio Shucks 270-054 does a fine job: http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=270-054

Good luck!

Yer pal,

Rob ;)

[boputnam]

Originally posted by alskinner
The one thing I haven't tried is plugging the computer into the same power strip as the amps. And, regrettably, that probably won't help.

Like me, you're gonna need another isolation transformer on that input, too.

Ground loops... :banghead: