What's the best Midrange driver?

[ClaudeJ1]

The most rare, quickly snagged driver seems to be the Altec 290 (probably the only one that goes to 300 Hz.). The rest are all flavors of JBL 1" and 2", the EV DH1A, Altec 902B, tons of different brands, etc.

I want to make my own wooden tractrix round horn, probably to 250 hz. It seems that with a 2" throat, I can make the horn shorter than a 1" throat for the same mouth size, which means I can have a bigger mouth/lower frequency with the 2" vs. 1".

Any qualitifed opinions and experiences on this? Any plots?

Claude

[ben.]

My take on it is that that you must go phenolic to get much below 500Hz. The JBL 2485 is a 4" VC 2" exit that fits the bill. I have jpegs of the cut sheets with FR graphs on a horn and tube.. They're about 150K each, so I don't want to attach them if you already have them, and they're not really legible if resized. Let me know if you don't.

I've been hunting for 290 for a while too, so I encourage you wholeheartedy to pursue a 2" throat!

[DrWho]

It's my understanding that 2" throats can go louder / lower because there isn't as much constriction in the throat (i think it's the cause of "horn throat distortion"?). Conversely, I think you will have greater erefficiency with a smaller throat and I'm certain about having better polars (and usually better high frequency extension). Ultimately I think the decision comes down to what kind of behavior you want the system to have - and then picking a horn topology and then mating a driver to it.

In other words, I don't think it makes sense from a design standpoint to pick the driver first??? I dunno - I'm just thinking out loud.

[ClaudeJ1]

I"m a firm believer in a 3-way system. I have had both 2 and 3-ways and the 3-way just plain sounds better. Now that I have some great passive subs with lots of cone area mated to my Khorns, I'm thinking, when I get the money later I can go the next step.......just thinking about the future here a bit. With subs, we effectively have a 4-way system anyhow, but 3-way crossover points. Having 80hz crossovers as optimum for both HT and 2 channel opertation from the same receiver (stereo mode gives me L, R, and sub's which sounds great). I never knew how much bass I was missing from the Khorns, but it almost seems like LaScalas would be good enough with subs, like many here. Better yet, maybe a straight axis 75 Hz horn with my existing subs.

Seems to me most drivers have to really stretch to get to 500 hz. 300 would be a target for me since the Klipsch bass units (Jubililees excluded) have a tough time getting to 500-600 without a ragged response and rolloff. Seems to me that 2" drivers with 4" coils would go lower more easily and handle more power. Since I don't plan to use much more than a few watts, it would make sense that the larger diaphragm could generate 400 hz. without moving as much as a 1" driver with a 1 1/2 or 2" voice coil.

Since PWK said the midrange is where we live, that willl be my next target after I tweak the tweeter section of the AA crossovers for my JBL 2404h's. Budget is limited right now, but I can work with what drivers I have. I'm just gathering info. for the future.

I'm intrigued by the Bruce Edgar designs, since they seem to represent a logical evolution to horn designs. Has anyone heard the Titans??

claude

[oscarsear]

I use the JBL 2482 cut off at 450 using phenolics. It has a good shoulder down to the 300s (specs on JBL pro under vintage drivers) but I wouldn't cut it that low and expect great performance from it. JBL also made a 2480 that's better still but they're tougher to find than the 290/16 Altecs. Trying to cut where you're suggesting is tough for the mid-range. Ever consider a four way with a mid-bass? Ale drivers from Japan have a full range of quality compression drivers but they are really, really pricey. You could also try using a cone mid-range but your probably looking at a 6 or 8 inch speaker that would make your horn humongous. I don't think Edgar crosses his midrange that low either. He's above 600hz if I remember correctly. Oris horns and Sierra Brooks both make radial tractix horns you can reference. Oris has a horn set-up to accept a 6 inch cone driver and a 2 inch compression driver...neither are cheap.

[DrWho]

Sounds like we have the same experiences / design goals [Y] I very much prefer the sound of lascalas + subs to that of the khorns + subs. I'm not sure how I feel about the Jubilee bass bins yet - whether or not direct radiating is the better way to go for the sub 80Hz material. One of my short term goals is to hear a 20Hz horn (which probably means building one myself)...but that's a totally different topic.

As far as the midrange - have you considered a hornloaded cone instead of a compression driver? They have no problems digging down to 200Hz and you can usually get up to 2kHz. It's not exactly an ideal place to cross to the tweeter, but some of the best mids I've heard have come from similar approaches. I'm sure with fancy phase plugs you could extend that another octave to 4kHz or so...

Another approach might be to take the Jubilee bass bin and apply the things that make it work to a higher frequency bass bin. 80Hz to 2kHz would be an octave shifted up from the Jubilee and would open the door to a lot of 2-way systems...I know it deviates from the classic 3-way approach, but PWK also mentioned that he preferred 2-way over 3-way. Modern driver technology is just getting to the point where it's a feasible option.

I think a really cool approach would be a fully hornloaded MTM design. With the K510 horn + K69 driver and a pair of 8" drivers behind the bass bin horn, it wouldn't need to take up a lot of floorspace either. It'd be a bit tall, but that's necessary to get the tweeter off the ground.

I've not heard any of the salad bowls, but I'm kinda weary of the design because they don't control the dispersion. I suppose many people enjoy direct radiators all the time so I kinda wonder how important the dispersion actually is....???

[Guest " "]

No sense in re-inventing the wheel.....build the Patrician IV.   Khorn bassbin with an additional 300hz wooden horn.

[tigerwoodKhorns]

The most rare, quickly snagged driver seems to be the Altec 290 (probably the only one that goes to 300 Hz.). The rest are all flavors of JBL 1" and 2", the EV DH1A, Altec 902B, tons of different brands, etc.

I want to make my own wooden tractrix round horn, probably to 250 hz. It seems that with a 2" throat, I can make the horn shorter than a 1" throat for the same mouth size, which means I can have a bigger mouth/lower frequency with the 2" vs. 1".

Any qualitifed opinions and experiences on this? Any plots?

Claude

Great Plains makes a 1.4" throat driver that goes down to 300Hz and has phenolic diaphragms. You need to call them because its not on their site. They are $325 each.

If you buy a pair, please report back.

[ben.]

Any details on the GPA driver? I've read that some their other updated designs have a shorter magnetic return structure that had the unintentional result of bringing the mechanical resonance of the unit into a range that caused audible problems in the driver's passband.

[linkalley]

the community m-200 is a sleeper!!!! 300 hz to 4000 hz so u must use a tweet in a 3 way. djk steered several of us on this critter. try it & you will like it!!!

[tigerwoodKhorns]

the community m-200 is a sleeper!!!! 300 hz to 4000 hz so u must use a tweet in a 3 way. djk steered several of us on this critter. try it & you will like it!!!

4000 hz is kind of low isn't it? I read that 5700 (as in he big heritage) is kind of low to cross over.

The Great Plains part is the 390. 300 to 8000 Phenolic, 1.4" throat, 120 watts $325 each.

[sfogg]

"The Great Plains part is the 390. 300 to 8000 Phenolic"

Don't count on 8k out of that either. I think the 290s rolls off around 4k or 4500hz too. From what I have read by 8kHz they are down around 10dB. I haven't measured one myself though.

Shawn

[ClaudeJ1]

No sense in re-inventing the wheel.....build the Patrician IV. Khorn bassbin with an additional 300hz wooden horn.

I am gathering information and the funds to make this happen later this year. I'm leaning toward a LaScala/Peavy FH-1/VOTT bass Horn/Bruce Edgar/ type of bottom with a 60-70 Hz. cutoff. I will be using large, multi-cone direct radiaor subs below 80 Hz from LF channel of Home Theater receiver (cheap and easy).

It seems most of these horn bins get funky after 300 Hz., but boy, what mid-bass definition and transients, so worth it. Since a 2" exit driver allow for a shorter, textbook Tractrix horn design for the same cutoff, I want to make a 200-230 Hz. Tractrix round horn,which "turns on" at about 300-350 Hz, so I can use first order networks. IOW, I'd like to have horns whose acoustic banpasses fit neatly inside the Xover networks, instead of pushing everything right to the edges all the time. For the top end, I will use a JBL 2404 H. Which can do 4,000 Hz, and easily handle the 10 W peaks that it will see when cranked up so it's a low profile 3-way, hopefully straight axis or single fold bass horn, with low Xover points and bigass DR subs.

I may even build an Edgar Titan derivative of sorts, I don't know, but it's nice to have choices for sure.

just call me "Full Wall"

[ZAKO]

From the frequency plots I have on the JBL 2404, 5000hz would be safer...I hear some stress at 4000hz (hardness) But maybe a steeper slope 48db would solve this at 4000hz. Then the community M200 would be possible.....Ill try this tonight. Remember the M-200 has been revised (M-200 A) Its response up to 4000 is smoother.

[tigerwoodKhorns]

"The Great Plains part is the 390. 300 to 8000 Phenolic"

Don't count on 8k out of that either. I think the 290s rolls off around 4k or 4500hz too. From what I have read by 8kHz they are down around 10dB. I haven't measured one myself though.

Shawn

That's not good. I figure the "390" is Great Plains in-house improvement of a "290" and that's why they named it so.

What driver can go to 300 safely and still make it to above 6000?

[sfogg]

"What driver can go to 300 safely and still make it to above 6000?"

On any of the Altec 300hz horns (803, 203, 311-90, 311-60..etc..etc) I would be surprised if the 288s could not do it in a home setup. The top end of them is good to about 10k, then they peak around 12k, then roll off. Cross at around 8kHz to the 2404. The higher you cross the 2404 the better they sound.

http://forums.klipsch.com/forums/thread/749000.aspx

Shawn

[ClaudeJ1]

Has anyone evert tried an Electro Voice DH-1? It appears to have response down to 400 Hz in their largest CD horn, the highest Gauss rating (2.1 Tesla), 2" throat. Looks like a winner on paper anyhow.

Claude

[mungkiman]

I certainly know a lot less than you guys, but University specs for the SA-HF mid driver boasts 90-10,000 cycles. Don't know if this would work for your application or not. Personally, I like the SA-HF very much.

[ClaudeJ1]

From the frequency plots I have on the JBL 2404, 5000hz would be safer...I hear some stress at 4000hz (hardness) But maybe a steeper slope 48db would solve this at 4000hz. Then the community M200 would be possible.....Ill try this tonight. Remember the M-200 has been revised (M-200 A) Its response up to 4000 is smoother.

Are you the same guy who gave John Warren the T35 frequency response plot? A friend of mine just loaned me that article and I'm building his self-contained tweeter crossover. Is this what you use in your system? He's got an LCR filter in parallel, and the air core chokes appear "lossy" enough not to need an autoformer or L-pad when using the 2404H with the K-horns. Is that correct?

Where can I find a community M-200?

Claude

[ZAKO]

Yes the plot of the T35 was done in a Anechoic chamber.many years ago.. I,m not familier with his xover..I use a Electronic xover. I have a pair of M-200 community drivers. Havent used them in quite awhile...I should get rid of them.