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In the Forum: Horn-Loaded Speakers
In the Thread: MacondoLite
Post Subject: Quite interesting ideas you put in there.Posted by Romy the Cat on: 8/19/2009
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 ayebee wrote:

The horns that Stereo Lab make are very good, especially considering the relatively modest prices. I bought the "Ultra-Fi" version of the 140Hz horns and they are of course not completely free of resonance ….

Present system consists of:
140Hz (3" throat) horn with Fane Sovereign 6" driver (120-700Hz)
250Hz horn with JBL 2440 driver (700Hz-2kHz)
600Hz horn with JBL 2420 driver (2-12kHz)
Bass is one Scan-Speak 8555 8-incher per channel in closed boxes. Quite insufficient.

I have a pair of EV 350's which aren't yet in use.
I do like the moves.

The 140Hz horn with 120-700Hz crossover. The decisions to have 3" throat was great – this horn will be loaded all the way to the bottom knee properly. I would not worry at this point about resonances, I more concerned about the wrong shape of the StereoLab’s upperbass horn’s back edge of mouth. I do not know Fane Sovereign. Look for 4’-6’ drivers with resonance frequency of 80-120Hz and low exertion. You will find a lot of them but very few of them will have high sensitivity. To find the right driver will be pain in ass. BTW, if you would like to rise then you might pick on eBay one “my” Fane Studio 8M. I think it is too big for 3” throat but you still never know how the driver will behave until you load it. If you run this channel up to 100Hz -1200Hz then I would not advise it but if you need to get from it just 600-700Hz then it might work. You will need to make absolutely minimum back chamber and to try it. It has true 103dB and with the huge frond chamber you might pick might be even 7dB in this horn. With this heavy load and with ultra-small back chamber you might not even need to high-pass the driver. Sure, a good 4” would be more fun but it might take for you forever to find it.

The 250Hz horn with JBL 2440 driver at 700Hz-2kHz. Interesting move with 2440. My only concern is that if you go with first order at this driver then it will be too identifiable as sourer and will offset your next channel too much. What I would experimenting be dropping crossover point on this china to lover, let say down to 1.5K and go with second or third low-pass order.  The idea of using the bottom knee of 2440 is good idea but you do not want your 700Hz-2kHz suck out a vertical cender image from your MF. Go get a digital crossover, connect it to your 700Hz-2kHz channel and play with it trying to found out how much max low-pass you room/distance will be able to afford. The 2440 in this region is absolutely obedient and it will allow you to cross it wherever you wish. One more thing, if you found that you 2440 channel can handle no more then let say 1500kHz (the number is purely random) then pay attention at what dB lever it would be. You might always drop 3dB (or much more) in your 2440 channel and add some output by “opening up” the upper range of your 120-700Hz channel. You shall not be afraid to run the sub 1000Hz channels in acoustic parallel. This is one of the “secret” weapons of this configuration – you can add “room loading” with your upperbass and lover MF without affecting anything. Do not forget that your 700Hz-2kHz and your 120-700Hz channels will be on opposite side of highly directorial MF – so you might do whatever you want on trim of acoustic coupling of their outputs.

The 600Hz horn with JBL 2420 at 2-12kHz. Again a good move. The 2420 is 1” version of 2440. It has thinner sound “full-range”, but since you killed the bottom 1-2 octave it is a very good choice. The horn is shallow, the dispersion is wide, and the HF attenuation in throe is very low. With good selection of the 2420 diaphragms you might get very good result. With this configuration you will be able to try any driver of your chose – anything will work in there. The only “thing” that I envision will be a conflict between your desire to have your 2420 to crossed lower (to save imaging) and your desire to have 2440 to crossed higher. Well, you need to interstate this subject.

The Bass and tweeter channels are not important now. If you use EV 350 then do not use first order with them. It would be interesting see with what kind of frame you came up for your 3 horns assembly.

The caT

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