OB 3-way Hybrid

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I've been following the beyond the Ariel thread with great interest and it has inspired me to try to do a hybrid OB (in the interest of space and bass impact).

Goals/assumptions/criteria:

1. Must cover entire spectrum ~ 20Hz-20KHz
2. Must be somewhat compact
3. Must be OB from ~200Hz to ~2KHz (low and high xover points)
4. Prefer ND midrange
5. System reference eff must be 95db or above
6. Impedance may not dip below 5 ohms
7. Active cross over with Deqx at ~200Hz. Active or Passive xover at ~ 2K.
8. Bass module can be native BR or Closed Box (with eq)
9. Low dyanamic compression
10. Room is moderate size 8'x21'x32' with listening seat at 3meters


Drivers considered at the top of the priority list right now:
- Beyma 18G40 Bass (BR or eq'd closed box)
- Beyma 12MW/ND OB Mid
- Beyma TPL-150 or RAAL 140-15D

Any feedback is welcome

Questions:

1. Any other drivers that I should be considering?
2. Any comments as far as meeting or not meeting the design criteria, or altering the criteria?
 
I agree with tinitus.
Ever considered something like a PR170M0, paired with maybe one of the more efficient Fountek ribbons? The Audax should do very well with a 2 KHz lowpass..around 96-97 dB/watt throughout most of its range, with moderate breakup peaking at around 100 dB from 3-8 KHz, and falls off steep after that. A high-end ribbon of sufficient sensitivity should mate very well with it, I would think. I don't see why a combination like this wouldn't have at least a slight chance of suiting your wants/needs. The only negative characteristic I don't like about that particular driver is the need to highpass at 400+ Hz, perhaps more on an OB. If you're like I usually am, and want a mid with a bit more low-end potential, perhaps a modded Visaton B200 as a mid could do well? Mainly your consideration of a 12" Beyma for a midrange provoked that recommendation I guess. And I'd be interested to hear from anyone who's done it too. If you're afraid a B200 wouldn't have enough maximum output or headroom for you, there are quite a few other choices as well, of course. Like several of the PHL mids, etc. But yeah, a 12" pro woofer with a ribbon tweeter is kinda pushing it, imo. I'd try to refrain from using it past 1KHz, if even that. Personally, I'd rather use nothing larger than an 8", perhaps more preferably a 6.5", and have it cover those exact ranges you specified, without anything in between. Oh and...don't expect to obtain 20 Hz from even the largest pro woofers. Even the most expensive biggest and baddest that WILL get that low will usually require a ridiculously MASSIVE vented enclosure.
 
Thanks for the feedback so far. Here are some thoughts based on the feedback.

The Beyma TPL-150 and RAAL seem to have the balls to get into the 1.8-2KHz region without an issue and have lower distortion compared to compression drivers. One issue I can think of is the polar response disparity as Duke has pointed out many times but I don't know how sensitive I'll be to that.

I haven't been able to find any independant measurements of the Beyma 12mw/nd but the distortion and fr plots at US Speaker seem to be very good up into the area where I would like to cross over with a very smooth roll-off. It's target market may be guitar and PA use but I don't understand why that would knock it out for high fidelity home use.

A single 12" has over 2 times the radiating area of a single 8" driver and 3.4 times the radiating area of a 6.5" driver while also decreasing the issues of using multiple drivers.

The other thing that enters into the goals is to have the least amount of dyamic compression as possible. It's my understanding that the higher the reference efficiency the better this is (although I'm not sure this is true in every case) The reference efficiency of the Beyma 12mw/nd is 2.3%; Audax PR170M0 is 1.8% and the Visaton B200 is 0.8%. I like the Audax but the other limitation with it is the low end cut-off. I don't like the idea of a bass driver having to work up into the 300-400 Hz region.
 
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Pardon me if I sound harsh, its not intended ... you dont like a woofer to play in the 300-400 region ... but you dont mind pushing a 12 woofer into the 2khz region, or past it with what is left behind the xo point

I bet that the 12" will have a much harder job than the 18" woofer

To be honest, I want the same thing as you do and would also like to use both 18" woofer and 12" mid, but have settled on a compression driver crossed around 1khz

If you push any of the drivers beond their sensible limit you may not reach your goal

NOW THAT YOU SEEM TO INSIST ON "OB" FORE THE MIDBASS DRIVER ... COULD THE 10/12" ALNICO TONE TUBBY BE A CONTENDER ... yeah, I know, no measurements, nada

But why the 12MW/ND when there is a similar 10MW/ND ?

Ribbons may be crossed at 2khz ... but from what I read they dont really like it too much
 
Tinitus, your comments of 12/10 versus 18 etc. seem reasonable. I actually went through part of the same thought process.

What I meant is that I don't like to go into the low midrange region with a driver that I'm also pushing into the sub region. Trying to reproduce lower midrange with a driver that has a fair amount of excursion demand just seems like I'd be asking for problems in the midrange. I was also looking at the number of octaves of duty. (20Hz-200Hz is a little over 3 octaves. 200Hz-2000Hz is is the same number of octaves).

I also looked at the 10mw/nd. It doesn't seem to get any further up and also has less radiating area. The FR and distortion actually looks better for the 12? Maybe there's better controlled de-coupling of the cone with the 12? There are a few examples of 12" drivers being used successfully into the 1.6K-2K region and higher such as Bastanis, PHY, etc.

I read somewhere in this forum that the critical range for OB is (subjectively or objectively, I can't remember) ~ 200Hz - 2KHz. However, the one thing I do like about dipole bass is the decreased complexity of room interaction. That said, it just seems very difficult to get dynamic range and the last octave with dipole bass without getting a divorce.

Any other RAAL or Beyma TPL-150 users out there that can comment on using them down to ~ 1.8K to 2K? Am I asking for trouble?
 
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Under normal conditions you probably wont see those woofers move at all :D

But I am no better myself ... I fancy a genuine 100db 12" PA mid driver myself, and use it all the way down :clown: 18" woofer will have a subamp with adjustable 6db gain ... well, maybe it will be a 21" :D

About the RAAL ... I think that Shin found the RAAL to sound better crossed high with 12db slopes

But trouble it is ... all of these drivers mentioned here are indeed very odd creatures in the hifi world
 
http://audioheritage.csdco.com/vbulletin/attachment.php?attachmentid=21755&stc=1&d=1167954174

frequency response of bass driver 2234H 15" .

http://audioheritage.org/vbulletin/attachment.php?attachmentid=4938&stc=1&d=1106766069

frequency response of the comp driver 2425 and horn 2344a without gain make up compensation. These were crossed 12db/oct in JBL studiomonitor 4435 at 1khz. Would the AMT mate with bass driver ? Im prepared for as steep crossover as I want . Also , whqat about using 2x TPL 150 / side (3 :confused: ) ? PAralleling up like the other does help in 1 khz- 4 khz & stuff .:confused: I also read tghe patent about ADAM's midrange amt , they use some trickery. Are Beyma mad to made claim 1khz and second order filter or they do something similar? Who tried it at all ? Yeah and the woofer response is 5 cubic feet vented tuned to 27hz... Helper second woofer makes it -3 at 27... )
 
Hello guys,

I have in the store room for 1 month, the CP380/M with DDS 1-90 ENG Pro, Beyma TPL-150 and Beyma 10MW/Nd. No time to build!

Just took out the TPL-150 and crossed it passively at approx 12kHz 1st order, on top of the Fostex 206e-sr. Did some quick DEQ to flatten it out, initial impression seems not bad. Need to run it in first I guess.

I think it will be at least another month before I can even get the box made for the 10MW/Nd, and then doing up a 2nd or 3rd order filter.

Will be driving the stuff with an Almarro 318B. I know, very very weird combination. But will not be plugging in the DEQ2496 with this.

BTW guys, with the flat impedance curve for the Beyma TPL-150,
a straight 2nd or 3rd order with additional networks are needed right?

SPECS :
http://profesional.beyma.com/ENGLISH/pdf/descarga.php?pdf=TPL150.pdf
 
Hey, thanks for your response. Upon examination of the ADAM site they write some sort of foam suspension is necessary to free it from resoncances and provide frequency response from 300hz, and powerful neo magnets. This made me think of the replacement diaphragms for ESS Heil AMT, these provide response 800hz - 20k from start, and cost reasonable 90 Usd.
 
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tinitus said:
I am not sure I would use a 12" PA driver much above 1khz
Originally posted by BHTX I agree with tinitus.

I don't agree. It's going to depend on the driver, of course. But most 12" pro drivers should have no problem there. And there are a good number of 15s and 18s that can do it.

In pro audio the tendency is to push the crossover point up - to protect the compression drivers.
 
Hello guys,

Today is Christmas day, Merry Christmas!

I'm free, so i took the opportunity to dust away the 10MW/Nd box and took out the driver. Hooked it up to the amp (no xover, full range) with the TPL-150 xovered at 12kHz first order for protection.

Sure, without a xover for the 10" to roll it off, it sounds like telephone quality, the Fostex 206e-sr in free air also sounds that way. But I put in Dire Straits and the electric guitars comes through really nicely. There is tone in it, which is what i want (some call it coloured). I am sure it can touch 2k no problem, anyway i'll be aiming to do about 1.5K with a zobel (the thing has Le1k of 1.7mH!). So I think there is potential once you fine tune it.

But yes, most 10-12" pro audio drivers may not reach that high, you need to check out the specs, the voicecoil diameter, graphs, etc etc....its the design. But then some 12" are actually midrange, so need to choose carefully and see what you are after. After all, Audiokinesis's Duke's speakers are using 10 and 12" stuff too.

And yes, the thing is quite dynamic sounding not dissimilar to fullrangers, can hear the "thrust" in it, not the usual audiophile drivers kind of sound.

Will give a writeup once its done, but don't hold your breathe it won't be anytime soon. :D
:D :D :D :D
 
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