High-efficiency 2-way...possible with 12" woofer?

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dmitriy167

dmitriy167

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Joined 2004
#1
Since I'm using a tube amp, i was thinking of ditching the 86 dB MorePees (Peerless 850122/Morel MDT20) I have now and getting something a bit more efficient. My target is around 92-93 dB into 8 ohms. It looks like the new Peerless HDS tweeter can do the job, but I need a good woofer that is efficient enough.

Assuming that I would run the tweeter without padding and that I would use 4 dB or so of BSC (should be around 300Hz due to cabinet width), the woofer would have to be 96-97 dB efficient, into pro sound territory. My budget for the woofers is no more than $160 per piece.

Would the tweeter and a 12" woofer integrate well? I'm concerned about beaming issues. My guess is that if I put the tweeter into a waveguide and then pad the response down a la Zaph, I would be able to get good power handling at a low crossover frequency. However, that requires more design difficulties and so I would like to avoid a waveguide if possible.

Woofers I have been looking at:

Eminence Delta Pro 12A:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=290-510

This one looks decent, but I can't get an F3 below 55Hz or so. Also, it has a 5 dB peak at 2.5 kHz that needs knocking down.

Eminence Kappa 12A:
http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=290-456&ctab=2#Tabs

Same peak as Delta Pro, Fs is lower, but Qts is too low for good bass response. I don't have the woodworking skills or space to do a horn.

Eminence Kappa Pro 12A:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=290-424

Decent response, low Fs, small peak at 2 kHz, but Qts is too low to be useful.

Eminence Deltalite II 2512:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=290-593

This one is interesting. Bass models perfectly for what I need, but it has a nasty rising response curve/breakup node. How would I get the phase tracking right if I knock it down with an inductor?

B&C drivers all seem to have a Qts that is too low, so I can't use those.

Beyma 12BR70:
http://profesional.beyma.com/ENGLISH/pdf/descarga.php?pdf=12BR70.pdf

Slightly low sensitivity, but just what I might need, although midrange distortion looks a bit high.

Beyma 12G40:
http://profesional.beyma.com/ENGLISH/pdf/descarga.php?pdf=12G40.pdf

Looks nice, has low distortion, BEAUTIFUL response, I can massage a good bass out of it, but out of my price range.

I don't have hardware measuring tools, so I would have to rely on Jay_WJ's method of simulating response. Since I'm using a tube amp, a flat impedance curve is essential. I played around with some of the Excel spreadsheets, and I'm not an expert at designing, but I'm OK with this being a learning experience.

Does anyone have any ideas/comments/driver suggestions?
 
#2
I am using NOW,

2-way open baffle,

tweeter is a compression driver with 105db spl and horn combo, you can pad it down. I suggest you use this approach, rather than std tweeter with 92-93db spl. If you use waveguide I am sure you have to do lots of adjustments and tweaking, if you don''t have appropriate equipment it is going be difficult.

my woofer is al' cheapo type, but you can use Eminence Delta 12" or equivalent as you suggested.

In open baffle configuration I have to use 2*12" per side to give me the bass. Hence my configuration is TWW, similar to Eminent Physics speaker system.

I cross at around 1.7Khz. Properly designed x-over the combo will sound good. I use digital x-over so easy to adjust.

cheers.
 
#4
ashok said:
" tweeter is a compression driver with 105db spl and horn combo "

What compression driver do you use and which horn ? I've been looking at some but they don't seem to go too low.
Thanks.
Click to expand...

There are a few good quality comp driver around, B&C and Beyma brands come to mind. These brands are recommended my many visitors here.

I am using B&C with good sucess, many others here also give their thumbs up. I have direct experience with B&C model, I am NOW playing B&C comp. driver,

model DE250 x-over around 1.7Khz, it can go lower to 1.5Khz. Also using B&C al cheapo horn ME10(lowest rec. x-over around 1.5Khz). If you have more money buy the DDS, Eng -90 horn, I heard it is very good.

DE250 is summary is very smooth and dynamic.

also I bought the cheaper model, DE10 x-over much higher at 2-2.5Khz. also very good.

All the B&C models above you can get from Parts Express.
 
#6
ttan98,

The DE250 looks like a good driver. I might end up using that, but I have questions. Firstly, can I use a round waveguide like the Dayton if I get an adapter? From the description, it might sound less nasal. Link: http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=270-310

Secondly, all the horn drivers have twin peaks in the impedance response. How would I smooth that out?

Also, any additional woofer advice to get a decent low end?
 
#7
dmitriy167 said:
ttan98,

The DE250 looks like a good driver. I might end up using that, but I have questions. Firstly, can I use a round waveguide like the Dayton if I get an adapter? From the description, it might sound less nasal. Link: http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=270-310

Secondly, all the horn drivers have twin peaks in the impedance response. How would I smooth that out?

Also, any additional woofer advice to get a decent low end?
Click to expand...


Hi,

I have tried the PE 10" circular horn, it is cheap and not very good if you expect high std. You are living in the States and able to access to high quality horn, I suggest the following:

option 1

cheaper, try RCF H100 horn at $28 each you can get it from Loudspeakers Plus. I am getting a pair. I have a test report on the compatibility with DE250, report with good result, except for a slight bum around 2Khz. You can equalise it easily. You x-over over as low as 800Hz!

option 2
DDS eng 1-90 circular horn is more expensive at $99 each from US speakers or cheaper at this site:
http://www.assistanceaudio.com

Both are good horns.

I use active x-over and don't have problems with impedances.
 
#8
also,

http://www.assistanceaudio.com/09_kits.html#tiny

this site offers package deal with their BMS and DDS horns and Ciare drivers at discount prices. Many people report the BMS 4550 to be very good too.

I believe the Ciare CIARE 12.00nd W1, not cheap is quite good, Audio Kinesis uses it in Stormbinger speakers.

You may find this site very useful.

I good combo is BMS4550, DDD eng 1-90 horn, and Ciare 12.00nd W1 driver. This will sound very dynamic and open with correct x-over. I am considering this combo for a similar system like yours. Not cheap but gives you good sound.

There you are more choices.
 
#10
The B&C drivers are good, i have used the DE900 a lot at home matet with 12" drivers Eminence Kappa pro12, good, Beyma 12LX60, imo among the best 12" you´ll find. Have changed hf to Beyma CP380M wich i find even better, also cheaper. Dont forget the Eminence PSD2002 driver, real value for money! You have to xo it at 1500 or higher thou.
 
#12
Instead of plastic hornflares it is quite fun and not very hard to build your own exponential wood horn. You don´t need many layers of veneer to get a structure that is "dead" inside the used range, best, of course, ist to go CSH, cat supervised horn, the slightest squeal or squeek is promptly dealt with.
 

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#16
Hoffman's Iron Law works here too. If you want efficiency and low F3, you give up size. Sufficient volume displacement from a smallish driver (and a single 12 is smallish to MY reckoning), equals high THD at above modest levels.
 
#19
I am happy with two Beyma 12P1000ND per side, but asking them to play lower than 50hz is asking for distortion. Depending on the distance to the speaker and preferred listening levels, a sub should free the single 12inch from the bottom octaves.
 
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