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Multi-Way Conventional loudspeakers with crossovers

Is it possible to cover the whole spectrum, high spl, low distortion with a 2-way?
Is it possible to cover the whole spectrum, high spl, low distortion with a 2-way?
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Old Yesterday, 10:46 PM   #6011
lbstyling is offline lbstyling  United Kingdom
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Join Date: Jul 2008
Quote:
Originally Posted by camplo View Post
I thought horn honk was something that can be eq'd out How are you voicing the driver?

If your driver supports down to 500hz then I'd think yes...

You want to trade me for my 1.5" 350hz? I need a 2" to use on the Axi...

I get honk when I play the driver too low it seams. This could be driver distortion as it is below optimum for a JBL 2452SL (4 inch dia), or the fact that I'm using a 2nd order filter, or somthing wrong with the crossover etc.

I beleve the 2452 has quickly rising distortion below 1000hz (circa 1% by 700/800hz, so it could well be this I am hearing, I have no way of knowing though.

The recommended crossover for a JMLC 350 hz is 520hz, but I do not know the steepness of the curve that assumes.

I bought the 2" inch JMLC with the purpose of having the flexibility of using different drivers (as I can 3D print up to 400mm3), so I might sell for a CD horn, but not looking to trade for a 1.5" sorry!

I am using digital active crossovers. (Hypex Fusion) + convolution and RePhase.

I was under the impression that 2" throats beamed too much for using up to 20khz? Or do I have that wrong?

Last edited by lbstyling; Yesterday at 10:48 PM.
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Old Yesterday, 10:48 PM   #6012
camplo is offline camplo
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Join Date: Feb 2019
Quote:
Originally Posted by lbstyling View Post
I get honk when I play the driver too low it seams. This could be driver distortion as it is below optimum for a JBL 2452SL (4 inch dia), or the fact that I'm using a 2nd order filter, or somthing wrong with the crossover etc.

I beleve the 2452 has quickly rising distortion below 1000hz (circa 1% by 700/800hz, so it could well be this I am hearing, I have no way of knowing though.

The recommended crossover for a JMLC 350 hz is 520hz, but I do not know the steepness of the curve that assumes.

I bought the 2" inch JMLC with the purpose of having the flexibility of using different drivers (as I can 3D print up to 400mm3), so I might sell for a CD horn, but not looking to trade for a 1.5" sorry!

I am using digital active crossovers. (Hypex Fusion) + convolution and RePhase.

I was under the impression that 2" throats beamed too much? Or do I have that wrong?
• Frequency Response: 500 Hz or Higher, 12 dB Octave Min

http://www.jblproservice.com/pdf/Dis...els/2452HJ.pdf

2" will beam more, that is correct
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Old Yesterday, 11:02 PM   #6013
lbstyling is offline lbstyling  United Kingdom
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Join Date: Jul 2008
Quote:
Originally Posted by camplo View Post
• Frequency Response: 500 Hz or Higher, 12 dB Octave Min

http://www.jblproservice.com/pdf/Dis...els/2452HJ.pdf

2" will beam more, that is correct
Just checked the measurements I found for it:

Shared album - lance bartlett - Google Photos

If this is correct, that would be the cause of the problem going below 800hz with this driver!
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Old Yesterday, 11:12 PM   #6014
camplo is offline camplo
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Join Date: Feb 2019
Quote:
Originally Posted by lbstyling View Post
Just checked the measurements I found for it:

Shared album - lance bartlett - Google Photos

If this is correct, that would be the cause of the problem going below 800hz with this driver!
Isn't it great how the manufacturers leave us hanging....I know that we can use distortion figures to fill in the blanks but thats usually after you've bought it and measured it on whatever horn...and then hopefully the info gets passed around the DIY community...

Those measurements don't show you what you want, those aren't measurements on a Jmlc 350hz horn....

You have measurement equipment right? Take some measurements...The horn is usually alimiting factor on the low range of the compression driver....if the driver just can't play that low, then its a different story...but yours is rated to 500hz

You would need to monitor distortion with your measuring mic to be confident about whats going on...

Last edited by camplo; Yesterday at 11:17 PM.
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Old Yesterday, 11:33 PM   #6015
camplo is offline camplo
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Join Date: Feb 2019
Quote:
Originally Posted by speedy6963 View Post
initial impressions, plays lower with less distortion than Radian 950 beryllium , needs some eq up top as expected. very good sounding
Quote:
Originally Posted by speedy6963 View Post
My comparison was on a replica TAD wooden horn from 400hz to 20,000hz. Just prefered the sound of the radian, both are good ....
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Old Today, 01:23 AM   #6016
fluid is offline fluid  Australia
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Join Date: Jan 2009
One of the claims of the Purifi Woofer is that Inter modulation Distortion is much lower than comparable drivers and that was one of their design intents.

I'm not trying to suggest it that it is better than the AE drivers you have only that in a space confined situation or one where large speakers are not wanted it offers something that was not available before and does not appear to be just smoke and mirrors.

Be wary of the specs gleaned from that power point as they are not really clear, there is 1mm peak displacement listed and a suggestion that there is only 1mm gap which may be been inferred from the 1mm displacement.

That sounds more like the mechanical limits of the driver and not linear xmax in the same way it would be listed for a dynamic driver.

Volume displacement is a simple formula Sd x excursion, just use the same units for both.
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Old Today, 02:50 AM   #6017
camplo is offline camplo
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Join Date: Feb 2019
Fortunately the JMLC modelling worked for me, I tried to model a SWH and I don't see it making the response or length of horn I expect...

In the video, the guy says @ 50:50,
Quote:
It can move out to 1 millimeter either direction in a (unintelligible...quite?) linear way
https://www.diyaudio.com/forums/atta...1&d=1590370960

So if xmax and xmech are on top of each other thats fine. I don't want to hit 123db anyway....its nice to know I'm not going to hit xmax or xmech, in the non PA setting.
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Old Today, 05:38 AM   #6018
vc08 is offline vc08  France
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Join Date: Jun 2014
Quote:
Originally Posted by lbstyling View Post
I get honk when I play the driver too low it seams. This could be driver distortion as it is below optimum for a JBL 2452SL (4 inch dia), or the fact that I'm using a 2nd order filter, or somthing wrong with the crossover etc.

I beleve the 2452 has quickly rising distortion below 1000hz (circa 1% by 700/800hz, so it could well be this I am hearing, I have no way of knowing though.

The recommended crossover for a JMLC 350 hz is 520hz, but I do not know the steepness of the curve that assumes.

I bought the 2" inch JMLC with the purpose of having the flexibility of using different drivers (as I can 3D print up to 400mm3), so I might sell for a CD horn, but not looking to trade for a 1.5" sorry!

I am using digital active crossovers. (Hypex Fusion) + convolution and RePhase.

I was under the impression that 2" throats beamed too much for using up to 20khz? Or do I have that wrong?
I use JBL 2450SL on a 240Hz jmlc horn and I have no problem of distorsion below 1khz... If the diaphragm is well centered (that is difficult to obtain).
Currently I use an active 24db/oct filter at 400Hz. It can work at 300 or 350Hz but That's risky.

In the past I've used several drivers on this horn, BMS coaxial driver was OK at 250Hz...with 8 watts SE 300B ,amplifier.

For Camplo, the real issue with this kind of horn (have build lots of jmlc horns in the past) associated with 2" CD driver is the lack of energy in the treble compared with the energy in the medium (due to of axis response).
My experience is that this kind of combo needs tweeter...But if you add a tweeter you need to look at the response of axis to choose the good filter, the good frequency, the good tweeter, to avoid a bump at the crossover frequency (with a CD tweeter for example, or with a High directivity tweeter but quite constant directivity).
It's probably the best way for the axi...But if you don't want a tweeter (the title of the thread is clear!), I think it's better to use a horn with less energy in the medium of axis...like a constant directivity one or like an hybrid (with conical part in the profile).

Last edited by vc08; Today at 05:40 AM.
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Old Today, 08:04 AM   #6019
vc08 is offline vc08  France
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Join Date: Jun 2014
It's difficult to explain the difference between horns, but we can exagerate and oversimplify (don't be too hard with me!):

JMLC horn could look like that. Good "loading", good frequency response on axis, induced directivity.
You "feel" lot of energy and presence in the medium (delicious for voices).
Click the image to open in full size.

Constant Directivity horn could look like that. Little less "loading", Less perfect on axis frequency response but quite good off axis, directivity better distribued.
You feel the energy more distribued.
Click the image to open in full size.

This picture can shows the difference between JMLC profile an "optimum" (a CD without defects?)
Click the image to open in full size.

I think that it depends on taste, on room, on listenning distance.
I personaly tend to prefer JMLC but with tweeter but I'd like to try a big "hybrid" profile.
Concerning the Axi I'm afraid that with a big JMLC horn the treble will be "shy" but that's a compromise...We can run in circle but that will be always a compromise...and a matter of taste
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