Which Driver to use for 100hz-500hz?

[KCCT82]

Hi,

I want to build a 4-way system that would do quite well from 20-20k, with 90+ sensitivity (size is not a big problem).

I'm using for each side (2) JBL 2242H for 20hz-100hz, then from 500hz-20K I'll be using the BMS 4592ND coaxial CD.

Considering the importance of the frequency range, I'm having trouble deciding on which driver to use for 100hz to 500 hz. The JBL 2206H in a sealed box or JBL 2020H sealed?

I have no experience with TAD, anyone have suggestions on whether the TAD 1102 is worth the price? Thanks

Keith

PS- i'll be using (2) behringer dcx2496 for all the x-over points 48db/oct

[Iain McNeill]

I don't have any experience with the particular drivers you describe. But I know the JBL professional line to be good quality and well designed. The only risk would be that JBL expects a certain cabinet configuration to make the drivers give their best but I also have faith in Theile-Small.

My only comment would be on the choice to put a XO point at 500Hz - right, smack in the middle of human voice fundamentals. That XO point will have such sensitive perceptual adjustment and I know I'd drive myself crazy trying to tune such a node. I really believe you need one driver for 350Hz to 1KHz as a bare minimum, then that critical band is under a known mechanical control.

Is it too late to reconsider your drivers?

[KCCT82]

Do you suggest crossing the 2242's at 350hz? then something like JBL 2012H for 350hz-1000hz, then the compression drivers?

actually the BMS coaxial CD works pretty well down to 350 provided you have a large enough horn to go with it.

Perhaps the JBL 2020H or 2206H for 100hz-350hz only?

and no, it's not too late to change drivers, i only have the BMS's right now, thanks

Regards,
Keith

[MaVo]

i bet you will allways get into a "critical" band while crossing over, depending on whom you ask. example: lowest voice fundamental may be below 100hz and highest overtones into the thousands. and who says only voice is critical?

i would rather say, make the transition as smooth as possible, regardless of crossover point. i think gedlee has done a very nice try on this with his summa, which is explained in other threads here in more detail than i could do.

my second thought is, why cant the bass driver handle up to 350 or 500 or even 1000hz, so that you get a 3 way instead of 4way? pro drivers are made to handle those frequencies, i think.

[Iain McNeill]

both the 2020 and the 2206 are excellent woofers but I can't recommend a 12" driver to be very good at 1KHz. You can see the off-axis response is getting a bit gnarley on the JBL datasheets.

I prefer a 3-4" midrange for good omnidirectionality but these might be hard to find for the power levels you're looking for.

I only advise caution in this band because the human hearing is very critical of human voice as we know this sound so deeply, especially female voice. My personal preference is for a single, very high quality driver to cover the 350-1KHz band which covers most voice fundamentals. (Barry White excepted )

[KCCT82]

Thanks a lot! I think I'll go with using the compression driver down to 300 or 350Hz.

Now i just need to find a horn that big

Keith

[vasyachkin]

two things

1 - you dont need 48db/oct crossover points everywhere even though they come free on the behringer. as compared to 24db/oct you will have more phase shift which is not the end of the world but if you dont need it then why ? you should experiment with both 24db/oct and 48db/oct settings to see what sounds IMHO.

2 - the range of 20hz to 100hz will be better covered by a TC Sounds (Audiopulse) unit than JBL imho. JBLs are designed to cover 40hz+ strictly in vented enclosures. TC Sounds are typically designed to work in either vented or sealed boxes and (depending on the model) to go down to as low as 16hz.

i have some 15" jbl speakers and a 18" TC Sounds LMS subwoofer ... forget it. in the lowest octave there is no contest. i respect JBL as a company but the standard practice in pro audio is to filter the bottom octave out, not reproduce it.

[Magnetar]

I'd horn load two of the 2242's -they are as good as it gets below 100 when horn loaded, and use the second pair as mid bass up to 500. A usable to 300 cycle horn with a compression driver will require a 200 HZ or lower flare and will have too much coloration and beam. A smaller 300 Hz flare horn used to 500 will sound better. If size isn't an issue horn load a good pair of 12's for midbass, use a 60 Hz flair straight hypex horn like used in the Edgar Titan 2 - Another excellent way to get killer bass in the right room is use multiple 10's and 12's (mid QTS but still efficient drivers) on an open baffle. Think big and thin

[vasyachkin]

horn load 18" JBLs ?

well it wouldn't really make them go lower ... just make them 10 times louder.

of course you can then use DSP processing to turn that extra SPL into extra low end reach but if you dont need the SPL itself then i think the price/performance ratio of that system would be off (when considering the cost of plywood and the very space it would occupy)

if you must have better efficiency than TC Sounds woofer then maybe 18" Aurasound with a pair of 15" TC Sounds passive radiators hanging off of it.

Aura has twice the linear displacement of JBL ... i mean if we must get silly might as well

just giving you ideas ...

[Magnetar]

Originally posted by vasyachkin
horn load 18" JBLs ?

well it wouldn't really make them go lower ... just make them 10 times louder.

of course you can then use DSP processing to turn that extra SPL into extra low end reach but if you dont need the SPL itself then i think the price/performance ratio of that system would be off (when considering the cost of plywood and the very space it would occupy)

if you must have better efficiency than TC Sounds woofer then maybe 18" Aurasound with a pair of 15" TC Sounds passive radiators hanging off of it.

Aura has twice the linear displacement of JBL ... i mean if we must get silly might as well

just giving you ideas ...

Of course it will go lower in a horn. Plus it will have lower distortion, plus higher output. Those 'stroker' 18's require massive power, plus the more the cone moves (paddling air) the less efficient they are at moving air at low distortion. I image six or eight strokers might be OK but that will take up more space then a single 1/8 space 20 Hz horn.

DSP processing? Why bother? What DSP system is at full resolution with a variable input? I listen at different volume levels and sine waves aren't much fun.