Damping 2307 horns

[2275xxx]

Hello JBLers,

I recently acquired a pair of clean 4343b, which replaced my 4333b.

Damping the 2312 in the 4333 was a great improvement and I wonder if I should do the same with the 2307.

This subject was discussed on other boards like DIYaudio, but I could not find any opinions on LH.

Did some owners of 434x monitors among you try to damp their 2307s ?
I am tempted, but I fear I would kill the balance and loose some of the magic...

Marc

[2275xxx]

Hem...
The subject does not seem to draw much interest.
I suppose the best way to know is to experiment.

http://farm4.static.flickr.com/3364/3647935730_28cc6b0f51.jpg

[hjames]

I hadn't noticed any ringing, with my L200s or my 4341s (both have short-horns at the moment) but maybe my ears aren't sensitized to it!

Always interested in improvements like this!
Tell us more!




Hem...
The subject does not seem to draw much interest.
I suppose the best way to know is to experiment.

http://farm4.static.flickr.com/3364/3647935730_28cc6b0f51.jpg

[toddalin]

I sprayed my 2312s with a rubber coating before installing them. Made a BIG difference in the ringing when you "thunk" the horn by itself. I don't know how much difference this makes once the driver is mounted and the horn is on the baffleboard, but it sure couldn't hurt. Any change would be subtle and I have no way to instaneously A/B the without/with.
http://www.largescaleonline.com/eimages/lsolpics/Team_Member_Pics/toddalin/Concrete_Rocks/H92_The_Build013.jpg

[BMWCCA]

If I ever heard my 2306s ringing, I'd probably wrap them in Bituthane, or some commercial sound deadening mats for car audio like this:
http://akamaipix.crutchfield.com/products/2001/154/h15410415.jpeg

[toddalin]

Unless you can instantaneously A/B the without/with dampening, how do you know you don't hear the ringing? :dont-know

As I noted, it could be very subtle and even limited to various frequencies/instruments. No, it's not going to sound like a bell. But it could manifest itself as a peak at a certain frequency. You could even mis-associate it with room acoustics.

[midlife]

If it is that subtle the difference may be difficult to quantify. Experiment and give us the results. I would think neutralizing any resonance would be an improvement.

[BMWCCA]

Unless you can instantaneously A/B the without/with dampening, how do you know you don't hear the ringing? :dont-knowI'm assuming if I could determine ringing in an A-B test, then I could hear something unnatural and irritating without the A-B comparo, no?

I go by the "if I'm happy, don't screw with it" school of acoustic engineering. In auto racing we call that the "butt dyno". I know the preferred method here is more data and less wank but my wife, her brother, and I have spent a nice evening listening to various CDs while we socialized and no one had any complaints. I'm not proposing anyone do it my way, or that I would be unwilling to experiment, or follow others suggestions for a mod that can't possibly do any harm, but I'd much rather just enjoy the music! :D

[pos]

Unless you can instantaneously A/B the without/with dampening, how do you know you don't hear the ringing? :dont-know

plotting the impedance with and without the damping material should give some clue

[Doc Mark]

I'm assuming if I could determine ringing in an A-B test, then I could hear something unnatural and irritating without the A-B comparo, no?

I go by the "if I'm happy, don't screw with it" school of acoustic engineering. In auto racing we call that the "butt dyno". I know the preferred method here is more data and less wank but my wife, her brother, and I have spent a nice evening listening to various CDs while we socialized and no one had any complaints. I'm not proposing anyone do it my way, or that I would be unwilling to experiment, or follow others suggestions for a mod that can't possibly do any harm, but I'd much rather just enjoy the music! :D

Hey, Phil,

I understand your reasoning, completely, and actually agree with what you have said. Though I do like to "test, experiment, and quantify" when I hear a problem, for most of my years, if my ears are happy, then I just call it good and have fun with it! Even as a working musician, I could tell if our PA or monitor system sounded "natural" to me. If it sounded good, didn't "feedback", and didn't leave my ears with tons of fatigue, then I left things as they were. IF problems manifested themselves, then of course, we would try to find them and fix them.

Here at home, we're very satisfied with what we have, and testing, experimentation, and such, are being done to learn, and to see how other things might sound, not so much to make our L300's sound better to us. We love them as they are!! I do hope to eventually get my subwoofer added into the system, but that's mainly to take a bit of the LF load off of the L300's, especially when watching movies, and not to change the way they already sound. Thanks for your comments on this. Take care, and God Bless!

Every Good Wish,
Doc

[toddalin]

I'm assuming if I could determine ringing in an A-B test, then I could hear something unnatural and irritating without the A-B comparo, no?

:D

No.

When I put the 2405 diaphram in the 2402, the results were very similar to a 2405 except that there was still a dip of about 1.5 - 2 dB in the ~8kHz range. If you listened to the system (on axis) with either tweeter in the system, they pretty much sounded the same, and both were nice. (Grumpy was here for this testing and can atest to this.)

But, when you played certain stuff, like a ride cymbal, you could note a slight difference when doing an instantaneous A/B comparison. The 1.5 - 2 dBA difference highlighted the cymbals. If you played the entire song though one tweeter then the other, you would probably never note this difference.

[hjames]

No.

When I put the 2405 diaphram in the 2402, the results were very similar to a 2405 except that there was still a dip of about 1.5 - 2 dB in the ~8kHz range. If you listened to the system (on axis) with either tweeter in the system, they pretty much sounded the same, and both were nice. (Grumpy was here for this testing and can atest to this.)

But, when you played certain stuff, like a ride cymbal, you could note a slight difference when doing an instantaneous A/B comparison. The 1.5 - 2 dBA difference highlighted the cymbals. If you played the entire song though one tweeter then the other, you would probably never note this difference.


Then if you can't hear a difference its probably not worth going through a lot of grief to resolve such a non-issue ...

I mean, isn't that the point with any of this?

Why spend the extra money to buy serious high-end gear if you don't hear a difference - its NOT to impress other members, I hope

[toddalin]

Then if you can't hear a difference its probably not worth going through a lot of grief to resolve such a non-issue ...

I mean, isn't that the point with any of this?

Why spend the extra money to buy serious high-end gear if you don't hear a difference - its NOT to impress other members, I hope

I don't agree. You can hear a difference, just not in every case or on all music. But under the right circumstances, an audible difference is there (in the case of the tweeters) and may be there (in the case of the horn coating).

How much R&D did JBL do to produce subtle improvements that one would probably never notice unless instantaneously A/B'ed with the prior offering?

How many variations are there of the LE-5? If you listened to the nearly dozen or so variations in a 3-way one after the other, do you really think you would hear a difference with each variation? But what if you could instantaneously flip between them? Then these subtle differences may stand out.

[hjames]

I don't agree. You can hear a difference, just not in every case or on all music. But under the right circumstances, an audible difference is there (in the case of the tweeters) and may be there (in the case of the horn coating).


I'm talking about damping 2307 (or 2312) horns, I'm not touching on the topic of swapping diaphrams into drivers they weren't made for. Thats the tweeter thing, right? Thats a completely different discussion than what was here.

Frankly, that issue was beat to death in another thread and wasn't what I or Phil or anyone was talking about in this thread anyway.

we really don't need to ruin this thread with all of that discussion.
Open another thread for all of that please ...

[toddalin]

I'm talking about damping 2307 (or 2312) horns, ...


Fine, but as I noted, here to the differences would be subtle (maybe even moreso) and may require an A/B/x test to differentiate.

There are certainly plenty of people on this forum who have damped their Altec and Emilar horns and reported the improvements.

[2275xxx]

If I were listening mostly to rock music and jazz I would probably be perfectly happy with a pair of L300/4333 in original condition.
But I also listen to a lot of classical music including chamber music etc…
In original condition if find the 4333s not versatile at all.
After damping the horns they became much more neutral and to my ears it was a huge improvement.

With the 4343s it is another story.
Without a doubt I could live with them as they are, without mod.
The “crystal glass” ringing of the 2307 is much less disturbing than the 2312’s bell sound, because it is not impacting the crucial mid frequencies.
I can hear the coloration, but I do not find it irritating.
Possibly this coloration contributes to the addictive personnality of the 4343s (this explosiveness…).

However, as I have an extra pair of horns at hand I am not too reluctant to experiment. Everything will be reversed if needed.
In order to be able to make the comparison I installed a damped horn in one of the cabinets only (using automotive material of the same type as in BMWCCA's picture).
Until now I have done only subjective listening, using a mono signal.

Before readjusting the Lpads the first result is obvious: a strong loss of perceived level from the 2420/2307 - I would say at least minus 3 or 4db.
My first impression was also that part of the excitement/magic was lost.
While the dynamic range had not changed, I felt that the “speed” was not the same anymore.
After rebalancing the levels roughly (only by ear) the difference is much smaller, although some of the initial impression is still there.
A gain in neutrality and a loss in speed/timing.
Further adjustments might allow me to regain completely what was lost, while keeping the gain in neutrality.

A serious comparison will require that I adjust the levels of all the drivers in a more “scientific” way.
As I do not have a RTA, I will make measurements with an old Technics frequency analyzer.
(@ POS: is it what you were suggesting ?)

I will update my impressions in a few days.

[hjames]

Fine, but as I noted, here to the differences would be subtle (maybe even moreso) and may require an A/B/x test to differentiate.

There are certainly plenty of people on this forum who have damped their Altec and Emilar horns and reported the improvements.

Sure, but Altec and Emilar are different shapes with different characteristics
are they exponential horns? ... A does NOT lead to B for different items ...

Do it if it makes you happy ...:)

Again, if you can't hear a difference, why would you spend any money on it?

http://www.kozystudio.com/bu2bu2/horn/eh820.jpg
Can't find Emilar bowtries like Tom used to use at a quick glance, but - you'll agree they are a different topology than the "trumpet horns" of the 2307 and 2312

[toddalin]

Again, if you can't hear a difference, why would you spend any money on it?



After investing hundreds/thousands of dollars on the speaker system as well as countless hours of your valuable time, why would you not spend an additional $2 for something that could yield a sonic improvement, and certainly couldn't hurt?


If I were listening mostly to rock music and jazz I would probably be perfectly happy with a pair of L300/4333 in original condition.
But I also listen to a lot of classical music including chamber music etc…
In original condition if find the 4333s not versatile at all.
After damping the horns they became much more neutral and to my ears it was a huge improvement.

[hjames]

After investing hundreds/thousands of dollars on the speaker system as well as countless hours of your valuable time, why would you not spend an additional $2 for something that could yield a sonic improvement, and certainly couldn't hurt?

previous poster 2275xxx seemed to imply it did hurt and took the excitement off his music ... with more info to follow ...

You and I both know its not about the $2 for Dumbdumb (or the automotive equiv that Phil showed) - that stuff is easy enough to find - but its the time and labor of opening those darned speaker cabs up and wrapping the horns - and getting the sticky gunk off later if its detrimental.

Spending a sunday to open them up, do all of that, then maybe undo it ...
especially now thats its prime season for outdoor activity!

Did JBL put that stuff on any of their systems?

[toddalin]

previous poster 2275xxx seemed to imply it did hurt and took the excitement off his music ... with more info to follow ...

You and I both know its not about the $2 for Dumbdumb (or the automotive equiv that Phil showed) - that stuff is easy enough to find - but its the time and labor of opening those darned speaker cabs up and wrapping the horns - and getting the sticky gunk off later if its detrimental.

Spending a sunday to open them up, do all of that, then maybe undo it ...
especially now thats its prime season for outdoor activity!

Did JBL put that stuff on any of their systems?

Previous poster was a little mixed, and the way I read it, it was the 2407 that he thought may have been detrementally affected. The 2312 seemed positive. Perhaps he'll clarify.

It's not the time and labor as I was changing out the horns anyway, as you seem to indicate that you will be doing soon. Now is the time for treatment before you do.

As for getting the "sticky gunk" off, these are keepers and it will never be taken off.

Early JBL Iconic horns were damped with a tar-like substance as Steve Schell can tell you. I heard these at Steve's home and they sounded wonderful.

[hjames]

Previous poster was a little mixed, and the way I read it, it was the 2307 that he thought may have been detrimentally affected. The 2312 seemed positive. Perhaps he'll clarify.

It's not the time and labor as I was changing out the horns anyway, as you seem to indicate that you will be doing soon. Now is the time for treatment before you do.

As for getting the "sticky gunk" off, these are keepers and it will never be taken off.

Early JBL Iconic horns were damped with a tar-like substance as Steve Schell can tell you.

Early Iconics horns, like most early horns, were soldered up wedge things with resonant flat surfaces, unless my memory is tweaked. Spun exponential type horns are a completely different structure, and while they may ring, they wouldn't rattle or buzz like sheet metal based horns would.
Maybe thats why they got damped?

Anyway, because you mentioned my gear - I have 2307, 2312 and 2397 horns to play around with, none of which I want to get gummed up, and damage any potential resale value.

For the L200 cabs, my first test will be using the pair of 2397 Ducklips on top, and perhaps try the 2312s later in the fall when it gets cold. Even tho I've already built the bumpouts boxes to use if I add longhorns to my L200 cabs, I haven't yet punched out the back of the cabinets ... and won't, if the Smith horns do their job with 1 inch drivers (I've been told they won't).

But thats why we test these things out personally, right?

[2275xxx]

Previous poster was a little mixed, and the way I read it, it was the 2407 that he thought may have been detrementally affected. The 2312 seemed positive. Perhaps he'll clarify.


previous poster 2275xxx seemed to imply it did hurt and took the excitement off his music ... with more info to follow ...



Well... I was trying to say that...

the stock 2312 is very colored, which makes it usuitable for many types of music - I do not like it;

the 2312 with damping is much more neutral, it is a huge improvement and I advise everybody to do it;

the 2307 is slightly colored, you hear it but is is not unpleasant;

the 2307 with damping is obviously more neutral.
But in the case of the 4343 there could be a tradeoff (neutrality vs PRaT).
Fine tuning will be needed to make it sound clearly better - or not - than a stock 2307;

I accept the fact that the more colored sound might be more pleasant to my ear than the less colored sound.
I could imagine myself choosing to go back to undamped horns.
I will take my time before I decide what suits me the best.

The only thing I know for sure: I am keeping the 4343s !

[Joe Alesi]

Hello JBLers,

I recently acquired a pair of clean 4343b, which replaced my 4333b.

Damping the 2312 in the 4333 was a great improvement and I wonder if I should do the same with the 2307.

Hello 2275xxx,

If it rings...stop it. One possibility for an all out job, would be to encase the horn in a cylinder (or box) filled with dry sand. A little effort would of course be required at the throat and mouth to seal off the cylinder. What is interesting about this method is that it can be made fully reversible and would probably offer the greatest degree of damping (depending on amount of sand).

Best
JA

[2275xxx]

Hello Joe,

The automotive product I used is very efficient.
It is horribly sticky and never dries.

After treatment the horns really sound dead.
A very "short" noise, with no resonance at all.
It would be interesting to see a plot of the efficiency of the product over the whole frequency range.

Of course - if you want to go back to original - removing these sheets of tar is not easy .
You would have to immerse the whole horn in some kind of solvent for a while.
In any case it wasn't an issue for me, as I had an extra pair of horns that had been sleeping in a corner for years.

[Ian Mackenzie]

Someone over on diyaudio.com (who's name escapes me right now) did this type of experimentation and used auto damping sheets on the 2312 to good effect.

There is no doubt the 2307 is better in the 43XX systems but it is what is is at the end of the day. Overall the 2307 with the 2308 lense is one of the more enduring combinations that seems to do more good things then it does bad.

One of the problems with the 2312 is the dispersion did not match well with the 15 inch woofer and the result was it honked badly at the crossover point in any position other than directly on axis. The power response was a dogs breakfast over its wide operating range which makes it awkward at best to get a good result out of.

I think acquaplas coating the titanium JBL diaphragms is a big step up in terms of improvement with the 2307 horn. Even this horn is unlistenable without the 2308 lense imho.

[richluvsound]

Hi Folks,

I didn't notice any difference on the TAD 2002 or the 2425 Ti dusted. I used
SIKAFLEX approx 5mm layer over the relevant areas. Not sure its worth pursuing . IMHO , Ian hits the nail on the head " 2307 is what it is !

Rich

[Fangio]

Would like to bring up another aspect that is not unimportant to me with these horns, to avoid coloration. It's the surface of the horn inside. As smooth as possible is desirable IMO, and they are not all like that.

Below you can see the longer 2312 with very rough paint surface inside (almost like the wrinkle paint on the outside), some aftertreatment like wet sanding is yet in order. And two short horns where I was lucky to get them with an inner surface almost as smooth as glass.

Think brass instruments..