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-   -   Wide-band Dipole Project (http://www.diyaudio.com/forums/multi-way/47592-wide-band-dipole-project.html)

DougL 13th December 2004 01:31 AM

Wide-band Dipole Project
 
I want to try a Dipole speaker with a "full-range" driver augmented as required.

My goals are:
Low distortion Drivers / Low distortion Speaker.
95 db capability with 10 db overhead
Moderate cost, say less than $500 US.
No crossover 300 to 3k, hopefully 200 to 4k.
Active crossover (Behringer DCX2496) with Gainclone amps.

I am looking at the AURA NS3-193-8A in a MTMWW.
Link to NS3

Positives: 100 Hz to 10 kHz response.
Under 1% distortion at all frequency’s of interest.
5 MM x-max allows 109 db for a pair at 200 Hz. (.5m baffle)

For a Tweeter, I am proposing the B&G NEO3
Link to NEO3
However, I am considering 3/4" and 1" dynamic tweeters as well.
Since the crossover isn’t required to be less than 2k, I am open to less conventional choices .

For a woofer, the Dayton 10" RS looks good.
Link to DAYTON RS270S-8 10"

I was looking for community input before buying the drivers.
I have started buying crossover parts and amps.

Thanks in advance:

Doug

tg3 13th December 2004 03:58 AM

Not sure you can get to 105 dB peak with the NS3 (80 dB), even when paired. And certainly not with chip amps.

Another consideration for the fullrange is the WR125S from Creative Sound Solutions.


http://www.creativesound.ca/images/product/WR125S.jpg


The Daytons look like a safe pick. How are you going to mount the woofers? An H-frame will not go up high enough for your fullrange choice.

Tweeters are dealers choice.

Elias 13th December 2004 04:05 PM

Sonmoro!

If you are interested in wide-band speakers, you might want to consider Beyma full range drivers e.g. 12AG100. SPL and distorsion should be no problemo in >200Hz even in dipole. You can also cross it over well beyond 4kHz.

http://www.beyma.de/seiten/beymatable/beyma_breit.html

- Elias

DougL 13th December 2004 06:11 PM

TG3;

Quote:

Another consideration for the fullrange is the WR125S from Creative Sound Solutions
Nice Driver, very nice driver.

Quote:

Not sure you can get to 105 dB peak with the NS3 (80 dB), even when paired. And certainly not with chip amps.
I was basing my assumptions on something I found on SL's site.

Quote:

The SS specification is 90 dB SPL for a single 21W/8554 driver. For two drivers in parallel add 6 dB and for rear radiation reinforcement from the open baffle add another 6 dB, which explains the high measured value.
Linkwitz Lab Models page

Given the NS3's 81 db sensitivity, add 9 db, 6 db for rear radiation, 3 db for double the area. That comes out about 90 db 1 watt. That should work out to 105 db with 32 watts.

Have I misinterpreted what I read, or is this not applicable? Its always a possibility.

I also ran SL's X-max calculator, and came up with 109 db at X-max with a .5 M baffle and 2 drivers.

Quote:

How are you going to mount the woofers? An H-frame will not go up high enough for your fullrange choice.
I was thinking of an 18" flat floor-standing baffle, possibly with a shallow U or H. I was envisioning something like the AVRO.

Thanks for your comments.

Doug

planet10 13th December 2004 10:38 PM

The WR125 is very nice -- just picked up 4 to play with.

Have a look at the Visaton B200... you can actually get away with no help on either end and add bits as you need.

dave

DougL 14th December 2004 12:16 AM

Elias;

Quote:

If you are interested in wide-band speakers, you might want to consider Beyma full range drivers e.g. 12AG100. SPL and distorsion should be no problemo in >200Hz even in dipole. You can also cross it over well beyond 4kHz.
Too many choices. :)

planet10;

Quote:

Have a look at the Visaton B200... you can actually get away with no help on either end and add bits as you need.
Those would be grand with the Pentode Amp/ Transconductance Amp you were talking about. :)

Thank you both. And I thought I read the Full Range Forum. :)

tg3 14th December 2004 01:25 AM

Quote:

Originally posted by DougL
Given the NS3's 81 db sensitivity, add 9 db, 6 db for rear radiation, 3 db for double the area. That comes out about 90 db 1 watt. That should work out to 105 db with 32 watts....

I also ran SL's X-max calculator, and came up with 109 db at X-max with a .5 M baffle and 2 drivers.

Well, a good spreadsheet beats a (semi)educated guess anyday. :blush:

Remember, on the SL spreadsheet D is the effective path difference, which is 1/2 the baffle width. So D=0.25 for a 20" (0.5M) baffle. After you add 6dB for radiation into half-space, you can go down to about 150 Hz. But I bet the WR125S will be much cleaner near xmax. :nod:
Quote:

Originally posted by DougL
I was thinking of an 18" flat floor-standing baffle, possibly with a shallow U or H. I was envisioning something like the AVRO.

Should work fine. With 2 RS270S, you should get down to about 80 Hz @ 105 dB with a 26" baffle (18" with 4" wings). You had planned on a subwoofer, right? :D

We're working on a similar design. I've chosen PHL drivers for the mid and woofer because of their high efficiency.

DougL 14th December 2004 03:04 AM

Quote:

Remember, on the SL spreadsheet D is the effective path difference, which is 1/2 the baffle width. So D=0.25 for a 20" (0.5M) baffle. After you add 6dB for radiation into half-space, you can go down to about 150 Hz. But I bet the WR125S will be much cleaner near xmax.
Good catch on D. Thanks. I guess I need to re-run the spreadsheet.
I suffer from an acute form of male pattern cheapness, so a $20 driver appeals to me. However, I agree your choice looks better. :)
I was also looking at the 4" Aura NS4-255-8D1,which would give me a bit more headroom, but there are no distortion or frequency response data available.
Quote:

With 2 RS270S, you should get down to about 80 Hz @ 105 dB with a 26" baffle (18" with 4" wings).
I like the way you think. I thought it would be more like 60 Hz with the 6db gain for half space, but I need to re-run those numbers, too.
Quote:

You had planned on a subwoofer, right?
I am planning a IB sub in a 4' by 5' by 12' insulated Storage behind the stairway. But I plan to finish the speakers first.

Thanks for your response. Please keep me posted on your progress.

Doug

DougL 25th March 2005 03:40 AM

Update.
I have a working prototype.
1 3/4" Dayton NEO
2 NSB
2 12" PE Buyout woffers

http://home.comcast.net/~djl329/BS2a.jpg

I am using the Behringer DCX2496 and A pair of Teac A-700 "monoblocks"

mantisory 8th September 2005 05:53 PM

Hi there
 
interesting...so did you ever get past prototyping these? and if so, how'd they sound?


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