Design: Horn High Sensitivity Speakers

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Helmuth,
Not only is it easier to have the phase correct at crossover with a 4th order network but the time alignment problems are also reduced greatly over a first order filter and two devices on a flat baffle, an often overlooked factor due to the physical depth of the two devices being very different.
 
Hi Guys,

Thanks again for all your opinions.
I have a quick update that will narrow things a lot:

1) I have at home my 45 SET amplifier. Power is 1.5 Watts, it sounds nice with 94db speakers, but I know it could do much better...

2) A friend, gave me a pair of JBL 2360A birradial horns (mouth = 80cm x 80cm).

3) I have been researching a compresion driver for this horns... I think the BMS 4591 is a good option.
http://bmsspeakers.com/fileadmin/bm...mpression_drivers/ferrite/bms_4591_t.data.pdf


Goal is to have an excelent sounding >100db speaker. Thinking in a super tweeter to improve directivity, and using the Omega Pro 18A up to 300-500hz, with a solid state amplifier until I get a better woofer.

Questions:
1) BMS 4591 is a 300hz-9khz driver. Any advantage in using something like the BMS 4590 that is a coaxial driver that reaches 20khz but need a crossover.
I am thinking 4591 with a supertweeter jbl2405 should be much better because of improved directivity.

Thanks...
 
Charly,
One comment that I will make about using a super tweeter is that you need to look at the minimum distance from the center of the 80cm horn lens to your super tweeter that has to be a little more than half the 80cm and that makes the center to center distance a minimum of 40cm. So no matter the design of the crossover you use you still have that distance between the on axis responses of the two devices and I have never seen anything like that where I could not hear that separation of the two sources over that distance. So I would much rather have a single device that can cover the range even if it is not perfect than use the two devices together. This may be a personal preference but I bet I get a lot of agreement on this. In the lower octaves it is not as much of an issue, but when you start dividing the frequencies in the upper range it does become a much greater issue.
 
Yes,
And JBL has been known to make some atrocious designs in the past. The plate loaded horns from way back in the past are an excellent example of horrible designs and they were in many of their early home versions of their professional products. I don't remember any part numbers but just because it says JBL on it doesn't make it a great component.
 
Have you looked at the beyma tpl150h . This has excellent sensitivity and distortion. It can usefully be used from the high 1khz region right through to the top end.

It is not cheap but I am really impressed with both the measured and subjective performance of these.

I use them above a 10 inch jbl bass-mid with good results.
 
Yes,
And JBL has been known to make some atrocious designs in the past. The plate loaded horns from way back in the past are an excellent example of horrible designs and they were in many of their early home versions of their professional products. I don't remember any part numbers but just because it says JBL on it doesn't make it a great component.

Yep, In specific I am referencing JBL Everest D550000. I dont think they sound horrible.
 
Of all the horrid sounding drivers that JBL has made, I think that the 2405 is one of the least objectionable. That said, I can't think of one good reason to use the 2405 instead of the 4590.

1) (as mentioned) the 4590 is designed to have the mids and highs come from the same source. Aligning the mids and highs with the 2405 will not work.
2) The 4590 has a crossover designed to make the driver act as one unit.
3) The horn you have employes diffraction to disperse the HF. Not optimal, but the same as the 2405. You will not get any advantage from the 2405 over the 4590/2360 combination in directivity.
4) The 4590 HF is manufactured the same as the mids, so there will be more continuity in sound with the 4590 vs the 4591/2405.
5) IMO, the 4590 HF sounds better than the 2405.
6) $ The 4590/4591 cost difference will probably be less money than that of adding the 2405 to the 4591. This is for a new unit, that will be under warranty.
7) Do not think of using another driver for 1khz up. A big advantage of the BMS is using the mid diaphragm all the way to 6.3 Khz. 300-6K, all the way through the vocal range, with no crossovers.
8) 1 & 2 add up to no sensitivity issues to address. The mids and highs will match.
9) At the crossover point there will be a better transition in dispersion with the 4590, instead of an advantage, the 2405 will introduce more chaos, not improve it.
 
Of all the horrid sounding drivers that JBL has made, I think that the 2405 is one of the least objectionable. That said, I can't think of one good reason to use the 2405 instead of the 4590.

1) (as mentioned) the 4590 is designed to have the mids and highs come from the same source. Aligning the mids and highs with the 2405 will not work.
2) The 4590 has a crossover designed to make the driver act as one unit.
3) The horn you have employes diffraction to disperse the HF. Not optimal, but the same as the 2405. You will not get any advantage from the 2405 over the 4590/2360 combination in directivity.
4) The 4590 HF is manufactured the same as the mids, so there will be more continuity in sound with the 4590 vs the 4591/2405.
5) IMO, the 4590 HF sounds better than the 2405.
6) $ The 4590/4591 cost difference will probably be less money than that of adding the 2405 to the 4591. This is for a new unit, that will be under warranty.
7) Do not think of using another driver for 1khz up. A big advantage of the BMS is using the mid diaphragm all the way to 6.3 Khz. 300-6K, all the way through the vocal range, with no crossovers.
8) 1 & 2 add up to no sensitivity issues to address. The mids and highs will match.
9) At the crossover point there will be a better transition in dispersion with the 4590, instead of an advantage, the 2405 will introduce more chaos, not improve it.

I have used a modded BMS4592 in orphean horn from BD design.
The biggest short coming is beaming in the treble. If you like megaphone like sound, ok, go for it.
Jbl 2405, and 077, have all a peaky sound. Never liked it.
If you want something better : go for Beyma TPL150.
 
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