MoD is playing with the Lansing heritage :-)

[MoD]

Burn hiiiim! Blasphemy!!

Well I do it out of love...

As I wrote in this tread

http://www.audioheritage.org/vbulletin/showthread.php?40723-Hi-from-a-new-member

It all started with JBL K(D) 130.

I got them (K 130) in really rough shape and recone them with D130 recone kit.
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[MoD]

First try was in some box which was laying in storage. Way to small box, but potential was there.

80842

Soon on this site I found plans for appropriate enclosure and built one test sample. It wasn't bad but it was humongous.

80843

[MoD]

I decided to build a pair of 4530 horns. Those are intended to be also test enclosures so it was imperative to keep the costs at minimum. I also acquired two 075 hi tweeters to replace Motorola piezo ones.

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In order to get some waf I painted the speakers.

[MoD]

This is where I really get on this, although there is no much bass below 60 Hz, I really liked those speakers.

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After initial enthusiasm, I was beginning to see potencial for improvements so I bought pair of 2445 compression drivers. Now, that opened a Pandora box, and soon I was buliding test horns. I liked the most truncated tractix 300 Hz horns, so I use test example to made mold for fiber-plastic.

The rest in tomorrow tense part of this story... :-)

[macaroonie]

Excellent :) Zilch would be proud of you

[1audiohack]

That’s quite a journey, lots of fun and good work!

Barry.

[MoD]

Thank You guys, it is still a journey, and level of fun is out of scale. :)

So mold has been done

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and first horn was finished. Inexperience got me this time, and I had to destroy mold to get horn of him, although i have treated mold with relase compound before plastic was applied. That really got me down, but test of the horn went good, so I use it to make another mold and horn.

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Making of this horns proved to be the most difficult part of this game, but I really want to build as much as I can by my self.

[MoD]

After finishing and painting, horns actually don't look to bad

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So I made the stands for them.
I wanted to make stands of aluminium, I could't get any, so they ended being build out of steel. Still looking for aluminium though.
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[MoD]

Considering I have never made any horns, I am very happy how it all turned out, although, there is a lot mistakes, in this build I have learned a lot, now I am confidential that next horns will be much better.
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I have also changed dampening material in connection chambers of 4530 from wool to 4 mm tick felt. This is much better to my opinion, because it is less damping material so the pressure is greater in the throat of horn. Which is good :D
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This is where I started tinkering with crossover networks. After a lot of tinkering I left it with third order 1000 Hz on D 130 and first order on 2445 drivers with 15 dB L pad attenuator which is by passed with 3.7 uF capacitor to boost some hi frequencies because for now I like the system to be two way.

[Earl K]

Nice Work!

:)

[Mr. Widget]

I’d say you are fearless... Impressive!
Keep it up!


Widget

[MoD]

Thank You.

It is easy to be fearless while one don't have to have results, and costs are reasonably low. These are my main speakers now, and listen them almost every day. They are very sensitive, dynamic and inviting for more listening, and I could live with them a long time, but there are also flaws in crossover network and limitations of drivers and horns which will drive me to research and build further. First, something is happening on crossover point. It looks I have a dip, cancellation, phase problem or something. Interesting it is not very noticeable during listening to music, vocal singing, but when speech is played some words or tons of voice are muddy. If that explains a problem...
That's why I am going to buy a measure microphone.
Other problems are lack of deep bass, and lack of hi tones (although to my taste very small lack)
To resolve problem (more like make a problem smaller :D) of deep bass I make (in theory) bigger bass horn.
I have "recalculated" Jensen Imperial built in horn for D130. I started that by placing 4530 connection chamber and throat in Imperial horn and scaling horn path.
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Friend from Croatian DIY-Audio forum made me Horneresponse simulation of that and bass is looking acceptable.
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What I do not like are big deeps around 280 Hz and 400 Hz (but that's backloaded horn nature). Since this horn would be really big, I started to look for plan for Hartsfield top loader. Idea is (if I ever get those plans) build one box (rough test box) and measure it, before I start to build my version (also test version for measure purposes) of Jensen Imperial.

[MoD]

I have acquired Umik1 measure microphone.

Since I have some suspicions about my 075 tweeters I have first measured them. What do You think?
Different colour graphs are measurements made at 1 meter distance 0, 15, 30, 45, 60 degrees.
I think they are loaded with those heavy (made of thicker material) diaphragms.

81980

I am thinking about purchasing this diaphragms;

http://www.soundspeakerrepair.com/speaker-parts-p/JBL-2404-H-Diaphragm/DIA-JBL

[hjames]

Very very cool work!!
I want the story to continue - tune for your ears!


Considering I have never made any horns, I am very happy how it all turned out, although, there is a lot mistakes, in this build I have learned a lot, now I am confidential that next horns will be much better.

I have also changed dampening material in connection chambers of 4530 from wool to 4 mm tick felt. This is much better to my opinion, because it is less damping material so the pressure is greater in the throat of horn. Which is good :D

This is where I started tinkering with crossover networks. After a lot of tinkering I left it with third order 1000 Hz on D 130 and first order on 2445 drivers with 15 dB L pad attenuator which is by passed with 3.7 uF capacitor to boost some hi frequencies because for now I like the system to be two way.

[gdmoore28]

Very very cool work!!
I want the story to continue

Me, too! It's a lot of fun watching you build your system and constructing all the cabinets and horns by yourself. Excellent work!

I'm not a JBL user, so I have no idea as to the answer to this question, but - is the D130 really the appropriate woofer for obtaining good bass response below the 60Hz that you report having now? When I was still working in ProSound, the D130 was widely regarded as a guitar speaker with an emphasis on midrange response.

GeeDeeEmm
http://www.lansingheritage.org/images/jbl/catalogs/1964/page42.jpg

[MoD]

Thank You both. It will continue for shure.

Nobody anything about 075? Oh well...

This is graphs of 2445 drivers in those truncated tractix horn I have made. I have plate amplifier, mono channel with dsp which I am using for measurements. Dsp cut all frequencies below 500 Hz so it was not necessary to add passive crossover elements to cut the low frequencies ( I did the same when I measured 075 but it was cut everything below 2700 Hz)
Measurement were made from 1 meter distance from the horn 0, 15, 30, 45, 60 degrees from axis.
I am very satisfied with results. :)

81992

This is graph of 4530 loaded with D130.

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All measurement were conducted outside on open space.

EDIT: @ gdmoore28; D130 was initially music reproduction driver (during fifthies) As JBL was expanding line of speakers, they came with more dedicated purpose speakers which were beter to use as music reproducers of part of music range, and D130 was advertised later as musical instrument driver. That does not make him bad for music reproduction, but it is heavy for implementation if you want to make it sound non vintage. It also has a lot of good aspects.
I like history and what 130 series represent, and so I have decided to build my system around him.
Knowing what I know now I would like to have 2227 drivers though.

[MoD]

Diy worm forced me to boy a pristine pair of 2227 drivers :D , I have also dig Phonic PA active crossover and Peavey CS800X amplifier. Crossover point is now 500Hz, and with no passive elements sound is much better. Except hi tones. In this setup there is no good way to boost hi tones. I should get some DSP...

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Peavey soon started to drift with DC offset, so I took him apart and started a refresh :blink: , and so...

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Capacitors are leaking, and I will replace all electrolitic capacitors everywhere in the amp.
This is the test of power supply filter capacitors, the rest is no better, and they have lost capacitance...


https://www.youtube.com/watch?v=aZwQgoLHI5U

[MoD]

I was wondering for a long time...; How about some nice big bass horn. So, I took for start Jensen Imperial bulit in, and heavily modified it for D130. I call it MoD's Imperial MK1 :D During last year from local recycling yard I was collecting bigger pieces of furniture partical boards, and last week I have built one. :bouncy:

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[MoD]

Oh, it sound marvelous! Some fine tuning should be done, so it will be even MK3 version but I love it! Nothing beats big bass horn! :D

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https://www.youtube.com/watch?v=gTinH3QSk5g

https://www.youtube.com/watch?v=rFy64JSUO7I

[Earl K]

Wow MoD!

Very Impressive!

Yes, I think your 075 tweeters need to have installed some new ( 077 ) diaphragms .

:)

[Kay Pirinha]

Hi MoD,

I'm very impressed, too, especially on your fibreglass/resin outcome. Your first mold might have been sticking due to it's surface which possibly might not have been smooth enough. But this is just an assumption, you know?

Btw, in that other thread you've told that you've reconed K-130 baskets with aftermarket D-130 kits. Why? Aren't there K-130 aftermarket kits as well? Optionally you could have reconed them as K-140's, which aren't that sensitive, but provide much lower bass. And agreed, genuine kits are prohibitively expensive :blink:.

OTOH and as yet said, a musical instrument driver most probably isn't the first choice as a HiFi speaker. Hence you might also have dropped 2205 recones into your alnico baskets which most probably will suit much better for your needs. Give your pristine 2227's a try also in your smaller bins and you'll see what I mean ;).

Best regards!

[MoD]

@ Earl K

Thank You.
Jes, i should buy 077/2405 diaphragms.

But..., 077/2405 has higher minimum crossover frequency. Too hi to reach D130 hi frequency reproduction capability. I would end with a hole in response.
So I plan to go 001 system way.
I am thinking about JBL 2425 compression driver. It should be close to 001 original 175 driver but cheaper. (Budget is limited :( )

@ Kay Pirinha
Thank You.
Surface was smooth. I can't tell if it was smooth enough. I was thinking a lot about that problem and come to two conclusions: I made mistake to make full lamination at once. Piece was stiff and only two layers piece instead wood be wobbly enough so it could be "maneuvered" from mold, and when it is off mold lamination could be made to full layers. Second problem in parts of horn near to throat which can not be lifted from mold like mouth part which can, throat must slide off mold and first few centimeters two surfaces slide in almost paralel motion.

Why D130 kits in K130 baskets? There is no smart explanation :D, I just wonted D130 and not K 130 or K140, or 2205 or... :D:D

At start D130 was music reproducer. Soon JBL developed beter suited driver for that application, and D130 became popular instrument speaker.
But, it can reproduce music. Put him big big horn and he can reproduce even The Prodigy's Charly (Trip in to bass and drum) with room shaking volume.
I have tried 2227 in 4530. More bass output than D130, no lower than D130. Horn itself limits bass extension.
But, in my version of Imperial D 130 has all bass I need, and 2227 is a bass monster.
This is MoD's Imperial responce D130 loaded in open space away from walls
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[Kay Pirinha]

I was thinking a lot about that problem and come to two conclusions: I made mistake to make full lamination at once. Piece was stiff and only two layers piece instead wood be wobbly enough so it could be "maneuvered" from mold, and when it is off mold lamination could be made to full layers. Second problem in parts of horn near to throat which can not be lifted from mold like mouth part which can, throat must slide off mold and first few centimeters two surfaces slide in almost parallel Motion.


I don't think you've made a mistake. I also would have done it your way. The reason is that the resin you've used, being it epoxy or styrene, uses some very small amount of dibenzoylperoxide catalyst, or let's say it better, a donor of radicals. Hence it cures in a chain-growth polymerization that always leads to some shrinkage, even if you're laminating glass fiber with the resin. This would lead to warpage if the workpiece isn't stable or stiff enough in that state.

Best regards!

[MoD]

That shrinkage could be a reason for horn stickin, specially on throath section. Need to destroy mould to get horn off really annoys me, and I found it unacceptable. So I have came to this conclusion (in theory for now); next time I will make only one or two layers of lamination, then horn goes of mould. After I take it of, I will apply some powder on mould and then put horn back in order to prevent worpage, and carry on with lamination to desired number of layers.

[MoD]

Diy worm strikes again. I was forced to purchase 2344a horns with 2426 drivers attached to it. That opens a lot of options...
Idea is tu use D130 in mk3 :D MoD's Imperial horn with 2344a/2426 for mid/hi; something like horn based 4430 only with higher crossover frequency (haven't decide yet, I will try 1800, 2400, 2800Hz and see what I like the most)

Meanwhille, I could try to put 2344 on top 4530/2227 instead 2445 in those tractix.
In Your experience, what would be upper crossover frequency to cross between 2227/2426? I have read that 4430 has some problems in upper bass/low midrange clarity. Can 2227 work nice to 1800 Hz?

[Mr. Widget]

Can 2227 work nice to 1800 Hz?Since it is a 15" woofer, it will be inherently beamy at such a high frequency, this will set you up for a far less than ideal transition between the woofer and the compression driver.


Widget

[MoD]

Meanwhile I have changed 2445 and diy tractix horns with 2344/2426 and have tried few cut frequencies. 1000 Hz works the best...

Have anyone ever thought about loading LA Scala bass horn with 2227 driver? I am thinking to build one LA Scala and try, but if anyone has any experience, I would like to hear other opinions...

[RMC]

Hi MoD,

RE "I would like to hear other opinions..."

I suggest you contact Barry (1audiohack) with regards to Klipsch La Scala. I remember he had an opinion about that model but I can't recall the details of it. He's also familiar with the 2227. This might be your best lead. Regards,

Richard

[1audiohack]

Oh boy! Short and direct. No offense intended.

First off, I have a couple of friends with LaScala's and, I think they sound like speakers in long pipes. They just do nothing for me.

2227's don't knock me out as direct radiators. I have really tried.

Crossing around 1K, 2220's. Over that? A 12" or 10".

You might get somewhere with a 2123 at close to 2kHz with your 2344's.

2344's really take some careful signal shaping to be their best.

All the best!
Barry.

[RMC]

Hi Barry,

I'm sorry my too quick post has caused you an inconvenience. It was not the intent. Will do differently next time. Regards,

Richard

[toddalin]

@ Earl K

Thank You.
Jes, i should buy 077/2405 diaphragms.




Not that easy. The diaphragms differ in architecture and an 077 may touch the phase plug of the 075. When I made this change, for testing purposes, I made shims to go between the phase plugs and diaphragms to correct this potential faux pas.

BTW, this is the spectrum for a stock 075 with an original diaphragm.


https://youtu.be/pbbS0QYK2_o


https://youtu.be/zicT8bw1ZmM

[1audiohack]

Hi Barry,

I'm sorry my too quick post has caused you an inconvenience. It was not the intent. Will do differently next time. Regards,

Richard

Hello Richard!

No inconvenience at all, none whatsoever. I just didn’t have a complimentary reply. :(

I hope you and yours are well!

My best.

Barry.

[RMC]

Hi Barry,

Thanks for the reply. We're all doing ok, hopefully your family too. Winter is slowly fading away here though still -10 C some nights...

We're not virus sick so that's good news nowadays when you have a look at TV. Doing income tax returns these days for family members. Got about a month of that. Not my dream work, gets a little more complicated every time, but somebody has to do it, and I'm unanimouly de-sig-na-ted for the yearly task. If I get some money back from the tax man when doing mine last, then it might go towards something audio, my reward...

The New year's or so gift I gave to myself is still stashed under a table in basement living room, haven't had time to play with it, wife hasn't noticed it yet! maybe better this way.

Btw I'll send you a PM for something else. Regards,

Richard

86039

[MoD]

After a while I am back. :)
@ RMC, 1audiohack, thank You for input about La Scalla and 075.

I have ditched idea about La Scalla, it is too short horn to expect bass output i desire. I am thinking about reconstructing MoD Imperial in front loaded horn, once in the future.

I have allso spent some time analysing my 075 problem.
I have come to conclusion that inside my 075 are some chinese diaphragms which only look ok (from distance :D) and that explain measurement i have on them on second page of this topic...

Time for new diaphragms...
Which one would You recommend?

I am in doubght on these, those are for 077 and I would have to make shims for phase plugs...

https://reconingspeakers.com/product/jbl-2405-aftermarket-diaphragm-16-ohm/

(https://reconingspeakers.com/product/jbl-2404-8-aftermarket-diaphragm/)

They look ok, but...

[ivica]

After a while I am back. :)
.....
I have allso spent some time analysing my 075 problem.
I have come to conclusion that inside my 075 are some chinese diaphragms which only look ok (from distance :D) and that explain measurement i have on them on second page of this topic...

Time for new diaphragms...
Which one would You recommend?

I am in doubght on these, those are for 077 and I would have to make shims for phase plugs...

https://reconingspeakers.com/product/jbl-2405-aftermarket-diaphragm-16-ohm/
(https://reconingspeakers.com/product/jbl-2404-8-aftermarket-diaphragm/)
They look ok, but...

Hi MoD,

I have bad experience with 'aftermarket 2405' diaphragms, I would not suggest You to waist your money.

Regards
ivica

[MoD]

I agree, original is original.

But...


K130 which start my story with JBL came to me in a trade (read: cheap). They went to storage and i went to internet. I liked what I read/hear. Ok, not all. Price wise idea was way above my range. So they sat on shelve for few years. Until, one day I said to myself; screw magnet recharging, screw original recone kit. No risk no profit, so I bought recone kit for D130 from Sound speaker repair, kits arrived, they looked good. As aviators used to say: If it look ok, it is ok. So they were reconed.

I do not think that my speakers sound the same as they would sound with recharged magnet and original recone kit. That said, i should say that i have never heard good original D 130. I have learned from this and other forums, asking people who had experience, listening D 130 on you tube (yeah, I know :banghead: ) about sound which is to be expected from D 130, and I have build mental "picture" of how they should work. And they fulfilled my expectations. :bouncy:

My conclusion is that for some models there are aftermarcet recone kit which for money gets big procentage of original sound.
I forgot to look at Sound speaker repair for 075 diaphragms when I wrote post about diphragms , but it looks that they are spending some effort to get a decent replacement par, and because of good experience with D130 recone kits, I think that I should risk hundred dollars for a pair of these:


http://www.soundspeakerrepair.com/mm5/merchant.mvc?Screen=PROD&Store_Code=SSR&Product_Code=JBL-2402-Diaphragm&Category_Code=DIA-JBL


It is going to make my 075 franken tweeters but all I need is good performance from 6000 Hz to 16000 Hz. No guts no glory :-)

[ivica]

I agree, original is original.

But...


It is going to make my 075 franken tweeters but all I need is good performance from 6000 Hz to 16000 Hz. No guts no glory :-)

Hi MoD,

I would suggest You may be Beyma CP21 or CP22 instead of "aftermarket JBL 2405/02 diaphragm"

https://usspeaker.com/beyma%20CP21F-1.htm


regards
ivica

[MoD]

Wow!

I did not know that Beyma is producing knock off JBL drivers. They are more than double expensive than Sound speaker repair diaphragms, and due to covid caused recession i will think twice before purchasing anything for audio hobby. :crying: It would be great to bring that 075 in some kind of useful working order for minimum money.

But both cp 21 and cp 25 are very interesting to me, and one day...

I have also came around this topic:

http://www.audioheritage.org/vbulletin/showthread.php?6368-Ring-Radiator-Comparisons&highlight=ring+radiator+comparisons

and I am in the middle of revision my 075 now, when I finish I will post results.

[ivica]

Wow!

I did not know that Beyma is producing knock off JBL drivers. They are more than double expensive than Sound speaker repair diaphragms, and due to covid caused recession i will think twice before purchasing anything for audio hobby. :crying: It would be great to bring that 075 in some kind of useful working order for minimum money.

But both cp 21 and cp 25 are very interesting to me, and one day...


and I am in the middle of revision my 075 now, when I finish I will post results.

Hi MoD,

http://www.audioheritage.org/vbulletin/showthread.php?26415-Beyma-CP21-F-tweeter&p=299484&viewfull=1#post299484

regards
ivica

[MoD]

Hi Ivica,

Wow, 5 dB less on Beyma. It also has a "bump" in response between 7 and 10 kHz. That could produce a lot of sibilance i think. At the end a lot better than my 075 with those wrong diaphragms.

And, speaking of diaphragms...

I have dismantle my 075.
At the end I don`t know what they should be, but I have noticed that central ring do not lay firmly on the pole piece. I have remembered Simply speakers video about installing 077 diaphragms in to 075 and I went through this topic;

http://www.audioheritage.org/vbulletin/showthread.php?6368-Ring-Radiator-Comparisons&highlight=ring+radiator+comparisons

So I made 0,19 mm thick rings to put below diaphragm central ring. That made difference. And I have measured;

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But, when I have install tweeters in the system, although, they performed closer to what they should, they had a lot of sibilance. And I mean a lot. Sssss`s were cutting ears. Measured system;

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It was obvious that around 7 KHz and past 10 kHz there are big resonant or distortion or breakup peaks. I managed to tame those peaks by apply heavy eq on dsp. That tamed peaks but bring another set of problems, sound is not right...

I have also found those diaphragms, they should be original;

https://www.simplyspeakers.com/jbl-replacement-speaker-diaphragm-d8r075.html

What do you think?

[robertg]

Those diaphragms are discontinued.

[Ian Mackenzie]

http://www.troelsgravesen.dk/Beyma-CP21-F.htm

[MoD]

So, at the and I have bought cheap chinese diaphragms for 075. 15 dollars for four. They are rubbish, but work better than old ones. So Beyma is in plans in the future.
In the meantime, one stupid question. Let say i have adapters which enable for 1" compression driver be mounted on horn for 2" drivers.
How stupid would be to take 2360 horns and marry them with 2426 driver? I will probably try, but it does not hurt to ask...

[ivica]

So, at the and I have bought cheap chinese diaphragms for 075. 15 dollars for four. They are rubbish, but work better than old ones. So Beyma is in plans in the future.
In the meantime, one stupid question. Let say i have adapters which enable for 1" compression driver be mounted on horn for 2" drivers.
How stupid would be to take 2360 horns and marry them with 2426 driver? I will probably try, but it does not hurt to ask...

Hi Mod,

if the mentioned 1" to 2" adapter is of proper length, I would not expect any problem that 2426 to be used with the mentioned 2360 horn.
As an example You can compare 2307 and 2311 horns. The first one is 1" horn while the second one is 2". Each of them were used over, say, 1200Hz, with 2308 lenses. The first one can be find in 4343/44/45 monitors, while the second one can be find in 4350/55 monitors.
On my personal opinion I would prefer 2311 & 2308 then 2307 & 2308.

regards
ivica

[ivica]

Hi Ivica,

Wow, 5 dB less on Beyma. It also has a "bump" in response between 7 and 10 kHz. That could produce a lot of sibilance i think. At the end a lot better than my 075 with those wrong diaphragms.

And, speaking of diaphragms...

I have dismantle my 075.
At the end I don`t know what they should be, but I have noticed that central ring do not lay firmly on the pole piece. I have remembered Simply speakers video about installing 077 diaphragms in to 075 and I went through this topic;

http://www.audioheritage.org/vbulletin/showthread.php?6368-Ring-Radiator-Comparisons&highlight=ring+radiator+comparisons

So I made 0,19 mm thick rings to put below diaphragm central ring. That made difference. And I have measured;

86493

But, when I have install tweeters in the system, although, they performed closer to what they should, they had a lot of sibilance. And I mean a lot. Sssss`s were cutting ears. Measured system;

It was obvious that around 7 KHz and past 10 kHz there are big resonant or distortion or breakup peaks. I managed to tame those peaks by apply heavy eq on dsp. That tamed peaks but bring another set of problems, sound is not right...

I have also found those diaphragms, they should be original;

https://www.simplyspeakers.com/jbl-replacement-speaker-diaphragm-d8r075.html

What do you think?

Hi MoD,

Using hi-pass crossover for UHF driver (JBL 075) You can easily remove the influence of the mentioned "hill" in the driver FR round 4kHz ~ 10kHz, especially if 3rd or 4th order Hi-pass would be applied, or a kind of band-stop width about 6kHzm Q=1.

regards
ivica

[MoD]

Ivica, thank You for the input.
I have made compensation for the "hill" in 075 response. Those chinese diaphragms, do not match originals by any means, but they do the job good enough. They are not permanent solution, but for now...

Why I did not buy beyma and put the end to this? Because, I still have illusions about horn point source (without bass of course ). :D Show will go on.

I have a vision about one horn from approximately 500 Hz to 20 kHz (would settle for 800 Hz to 16 kHz). So, I have made a deal for two copies of 2360. Dimension wise they are very good, but they are made of more layers than originals, so they are thicker.

If I could afford, I would buy BMS 4590 and that would be it, but money is tight so let's play.
2445 with smooth titanium diaphragms can be made to play flat to 20 khz (I have done it already, but brake up mods at 6.5 kHz, 8 kHz, and 12 kHz, make sound very harsh. 2445 are good for use between 500 and 6 kHz.
I have also jbl 2426 I am going to ask local machinist to make me adapters from 2" to 1" throat, long 76mm. I am counting on response rise to about 3,5 kHz so quite attenuation will be required, and I plan to use that to set 800 Hz crossover point. If I could make 2426-2360 work from 800 Hz to 16 kHz I would be very happy.

[1audiohack]

...Let say i have adapters which enable for 1" compression driver be mounted on horn for 2" drivers.
How stupid would be to take 2360 horns and marry them with 2426 driver? I will probably try, but it does not hurt to ask...

That has certainly been done. I tried it and didn’t notice a real difference in the very high end and went back to 2” drivers. A 2405 fixes it. :)

The reason for my late reply is that I had measurements of this set up once upon a time but they are gone.

The JBL 2427 was made just for this type of use.

All the best.
Barry.

[Mr. Widget]

Barry, do you mean the 2327 1” to 2” adapter or the 2427 driver with a 1.75” diaphragm and integral 1” to 2” snoot?


Widget

[MoD]

That has certainly been done. I tried it and didn’t notice a real difference in the very high end and went back to 2” drivers. A 2405 fixes it. :)

The reason for my late reply is that I had measurements of this set up once upon a time but they are gone.

The JBL 2427 was made just for this type of use.

All the best.
Barry.

Wow! I was not aware about 2427. That is a good news! It is possible!
Bold part: More or less all compression drivers, after mid range fall with output on hi frequencies. But, one can EQ them flat (more or less :D). That is not good Idea with 2445. But can be done with 2426. I do not have to go to 20 kHz; 16 kHz will do.

Pity about those measurements.

How long is 1” to 2” adapter on 2427?

[tomee]

Wow! I was not aware about 2427. That is a good news! It is possible!
Bold part: More or less all compression drivers, after mid range fall with output on hi frequencies. But, one can EQ them flat (more or less :D). That is not good Idea with 2445. But can be done with 2426. I do not have to go to 20 kHz; 16 kHz will do.

Pity about those measurements.

How long is 1” to 2” adapter on 2427?


I measure 13.3 cm from the front of unit (at the flange for the 2" opening) to the silver ring at the front of the driver (where the threaded on adapter will butt against the 2426/2427 threaded body).

Your work on this is inspiring - thank you for sharing!!88867

[MoD]

Thank You tomee!

In the meanwhile, I was at the local lathe guy, and menage to convince him to make me two adaptor pieces, heavy influenced by 2327 adaptor, which lenght is 105mm which is 2.8 cm shorter than this 2427 adaptor. Hmmm. We will see what will be responce whit my adaptors.

P.S. Sharing is caring. :D And dialog with different people around the world with similar interest is fun and educative.

[tomee]

Thank You tomee!

In the meanwhile, I was at the local lathe guy, and menage to convince him to make me two adaptor pieces, heavy influenced by 2327 adaptor, which lenght is 105mm which is 2.8 cm shorter than this 2427 adaptor. Hmmm. We will see what will be responce whit my adaptors.

P.S. Sharing is caring. :D And dialog with different people around the world with similar interest is fun and educative.


Hi! Actually, this makes sense, as the front 'horn' on the 2427 is a screw on piece, and the 2327 adapter for the 2425 is flanged, so it will be shorter by the threaded portion (which does look to be about 28mm). If I could take this apart I would, to show you, but I can't seem to get it off.

I think the 2427 was meant to be a replacement for the 2425+2327 in the 2" exit installations, so it could be exactly the same. It is essentially the same as a 2426 threaded (screw on?) driver.
I have only one 2427, bought 'by accident' on eBay when I put in a low bid not expecting to win but did in the end.

[MoD]

I think that only relevant measurement is length between driver exit plane, on the one side and end adapter mounting plate on the other side. Screw on piece enters threads inside adapter so it does not contribute to extend length. That is why I think I am 2.8 mm short if we take 2427 adapter as ethalon. I also think that 2.8 cm will not make significant difference.