Hi,
For a small dedicated room I want to try a 3way passive OB. I have done the mid OB before and was amazed by the increase of soundquality of the driver compared to it sealed. I like the OB concept very much.
For the low woofer I am thinking about one Eminence 15", or 2x12" per side.
I know it is discussed earlier which woofers sounds best but every situation is different.
I hope to hear what you think is best for my situation:
- My room is only 3,8x4,2 meters (16m2) and the speakers can be placed at one meter from the wall.
- I want it fully passive (without EQ), because I like my amp a lot, so why buy more (maybe later)
- I hope to get in the 30's hz. until 500/700hz. (U frame, or H, or very thick _ baffle )
- Middriver Tangband w4-1320s in seperate small baffle (with Tweeter)
- Ribbon tweeter (might be updated with AMT)
I focus mainly on SQ, so SPL is not so important.
On the other hand I can use the room as a dedicated home theater (as I did earlier, but now its only for listening). So another idea is to build an IB Sub with 15 or 18's (in that case one or two 12" for the bass would be oke?).
Here I can buy soms older NOS Eminence woofers; the Delta 12 (not 12A). Or newer Kappa 15A. Or Betas, and so on.
Of course the Alpha 15A is also an option, but I see some people don't like the muddy sound, (while others love them).
AE drivers would be to expensive for now, I look for a relative cheap sulution.
But the Bass should be deep, thight, detailed but also good in upper midbass.
I am curious what you guys think.
Thanks in advance!
For a small dedicated room I want to try a 3way passive OB. I have done the mid OB before and was amazed by the increase of soundquality of the driver compared to it sealed. I like the OB concept very much.
For the low woofer I am thinking about one Eminence 15", or 2x12" per side.
I know it is discussed earlier which woofers sounds best but every situation is different.
I hope to hear what you think is best for my situation:
- My room is only 3,8x4,2 meters (16m2) and the speakers can be placed at one meter from the wall.
- I want it fully passive (without EQ), because I like my amp a lot, so why buy more (maybe later)
- I hope to get in the 30's hz. until 500/700hz. (U frame, or H, or very thick _ baffle )
- Middriver Tangband w4-1320s in seperate small baffle (with Tweeter)
- Ribbon tweeter (might be updated with AMT)
I focus mainly on SQ, so SPL is not so important.
On the other hand I can use the room as a dedicated home theater (as I did earlier, but now its only for listening). So another idea is to build an IB Sub with 15 or 18's (in that case one or two 12" for the bass would be oke?).
Here I can buy soms older NOS Eminence woofers; the Delta 12 (not 12A). Or newer Kappa 15A. Or Betas, and so on.
Of course the Alpha 15A is also an option, but I see some people don't like the muddy sound, (while others love them).
AE drivers would be to expensive for now, I look for a relative cheap sulution.
But the Bass should be deep, thight, detailed but also good in upper midbass.
I am curious what you guys think.
Thanks in advance!
You may want to consider qnty 4 x 8in woofers in slot loaded open baffle with U frame wings. I find that this type of setup gives advantages of OB bass while being able to reach 30 Hz easier. I have done this with qnty 4 x 6.5 in woofers and it sounded very nice. The other advantage is that it keeps the frontal profile a manageable 12in so you don't have an over powering visual presence that a flat 30Hz capable OB would take in room.
Details here:
http://www.diyaudio.com/forums/full-range/249984-cheap-fast-ob-literally.html
My setup was able to achieve flat (with exception of room modes) response from 30Hz to 340Hz XO with no EQ only low pass filter. This is with a PRV 5MR450NDY as the full range top.
Details here:
http://www.diyaudio.com/forums/full-range/249984-cheap-fast-ob-literally.html
My setup was able to achieve flat (with exception of room modes) response from 30Hz to 340Hz XO with no EQ only low pass filter. This is with a PRV 5MR450NDY as the full range top.
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I've had great results with two Eminence Beta 15A's per side in a 50cm wide open baffle. With your placement, though, you might be struggling to get to the low 30's.
What I learned from my OB projects, was that you need ample nominal sensitivity from the drivers, preferably large Xmax and more cone area doesn't hurt either. And a thing to look for is the resonance frequency of the driver, since that will ultimately decide how low you can go.
One other thing is to match your middriver sensitivity to the resultant sensitivity of the bass section. My last attempts had a slight problem with too much bass, since the two series-connected Eminence drivers resulted in a sensitivity of ~90dB/2.83W/m, and the Seas coaxial I used was slightly under that.
If you want to use Eminence drivers, I suggest preferring the Beta over the Alpha. Better sound, better Xmax and lower Fs.
What I learned from my OB projects, was that you need ample nominal sensitivity from the drivers, preferably large Xmax and more cone area doesn't hurt either. And a thing to look for is the resonance frequency of the driver, since that will ultimately decide how low you can go.
One other thing is to match your middriver sensitivity to the resultant sensitivity of the bass section. My last attempts had a slight problem with too much bass, since the two series-connected Eminence drivers resulted in a sensitivity of ~90dB/2.83W/m, and the Seas coaxial I used was slightly under that.
If you want to use Eminence drivers, I suggest preferring the Beta over the Alpha. Better sound, better Xmax and lower Fs.
Thanks xrk971 for the good idea and the effort.
I looked into it also earlier but found the low db output a bit of a downside.
But that probably can be fixed with more woofers.
The small front is a nice benefit indeed, but not necesarry.
Will the SQ in the upper mid region stay the same with this concept.
And are the parameters of the woofers (low fs, high qts, low mms) evenly important as with OB?
The price of 4x8" per side , 8 in total is however a problem.
I looked into it also earlier but found the low db output a bit of a downside.
But that probably can be fixed with more woofers.
The small front is a nice benefit indeed, but not necesarry.
Will the SQ in the upper mid region stay the same with this concept.
And are the parameters of the woofers (low fs, high qts, low mms) evenly important as with OB?
The price of 4x8" per side , 8 in total is however a problem.
@Adolf Corkscrew, That matching driver sensitivity is something that I have to look into indeed (almost forgot), but I dont know really how.
What was it again?, double the woofers, is +3db, and OB is also +db, only the low frequency gets higher with smaller baffles.
My mid is about 89db.
The Eminence Kappa 15A Qts is very low (fs33hz, 100,5db, Xmax 4.0, mms 76gr, Qts only 0,32)
The Eminence Beta 15A has nice specs indeed (fs 35, 98,2db, Xmax 4.0, mms 60gr, Qts 0,58)
But in the baffles that I want to use (U, H, or thick _ ) how would it come out and match my mid?
What was it again?, double the woofers, is +3db, and OB is also +db, only the low frequency gets higher with smaller baffles.
My mid is about 89db.
The Eminence Kappa 15A Qts is very low (fs33hz, 100,5db, Xmax 4.0, mms 76gr, Qts only 0,32)
The Eminence Beta 15A has nice specs indeed (fs 35, 98,2db, Xmax 4.0, mms 60gr, Qts 0,58)
But in the baffles that I want to use (U, H, or thick _ ) how would it come out and match my mid?
@Don Camio
The best way to do it is to start with the bass section. Build it, measure it, then start matching the midrange. You can try to calculate and simulate, but that will only get you guidelines.
For your midrange sensitivity I would start with the series connected Eminence Betas. That should get you in the ballpark in a 50cm wide open baffle, no need for U- or H-frames. Thus less worries of resonances. If the sensitivity of the bass section appears too low, you get 3dB more for parallel connecting the woofers.
I can only tell you how they measure in a straight OB, since I have'nt tried anything else.
Oh, and be prepared to use large coils. I had to use an electrically third order low pass for the series Betas, 22mH - 78µF - 10mH.
The best way to do it is to start with the bass section. Build it, measure it, then start matching the midrange. You can try to calculate and simulate, but that will only get you guidelines.
For your midrange sensitivity I would start with the series connected Eminence Betas. That should get you in the ballpark in a 50cm wide open baffle, no need for U- or H-frames. Thus less worries of resonances. If the sensitivity of the bass section appears too low, you get 3dB more for parallel connecting the woofers.
I can only tell you how they measure in a straight OB, since I have'nt tried anything else.
Oh, and be prepared to use large coils. I had to use an electrically third order low pass for the series Betas, 22mH - 78µF - 10mH.
Hi,
Its relatively small room so 2x15 per channel as a minimum
makes no sense. Unless your amplifier is flea powered high
sensitivity makes little sense in a small room, especially
as you say your interested in SQ more than SPL.
Personally I'd build these :
https://sites.google.com/site/undefinition/diy-sunflowers
YMMV but big speakers hardly ever integrate well
in small rooms, and tight and deep bass is going
to be problematic with a near square room and
the near spacing of pairs of room modes.
With the two lowest room modes at 41Hz and 45Hz
(then 67.6 + 71 Hz, then 70+73, 82+84, etc.), (used h=2.5m)
30Hz bass is going to be practically difficult with no EQ.
rgds, sreten.
Its relatively small room so 2x15 per channel as a minimum
makes no sense. Unless your amplifier is flea powered high
sensitivity makes little sense in a small room, especially
as you say your interested in SQ more than SPL.
Personally I'd build these :
https://sites.google.com/site/undefinition/diy-sunflowers
An externally hosted image should be here but it was not working when we last tested it.
YMMV but big speakers hardly ever integrate well
in small rooms, and tight and deep bass is going
to be problematic with a near square room and
the near spacing of pairs of room modes.
With the two lowest room modes at 41Hz and 45Hz
(then 67.6 + 71 Hz, then 70+73, 82+84, etc.), (used h=2.5m)
30Hz bass is going to be practically difficult with no EQ.
rgds, sreten.
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Hi Sreten,
Nice speakers indeed (with a good tweeter) and good info on the link.
I like to use my bamboo driver with the ribbon tweeters (I love the speed of fast drivers).
30 hz indeed is probably impossible. And I dont need the high sensitivity. My amp is a hybrid 150watt per channel.
Now I use a closed box for bass, and i dont miss the sub lows. It would be nice but not a must.
At this time I am thinking of one 15" per side, maybe the beta15a, or the A&D r1524.
Nice speakers indeed (with a good tweeter) and good info on the link.
I like to use my bamboo driver with the ribbon tweeters (I love the speed of fast drivers).
30 hz indeed is probably impossible. And I dont need the high sensitivity. My amp is a hybrid 150watt per channel.
Now I use a closed box for bass, and i dont miss the sub lows. It would be nice but not a must.
At this time I am thinking of one 15" per side, maybe the beta15a, or the A&D r1524.
I have the TB 1320 bamboo driver and think it's very good. I sit the speaker on H-frames using the Alpha 15 and the combination is great. I have the TBs in small sealed boxes. Sitting the speaker on a sealed sub also works. I think whatever you decide to do with the bass the 1320 will work really well. One suggestion would be to use a subwoofer amp to blend into the overall sound. Good luck and enjoy!
Hi,
When people say that I read innaccurate drivers.
This very mundane tweeter is as fast and flat as you could ever want :
Dayton Audio ND20FB-4 Rear-Mount 3/4" Neodymium Dome Tweeter
and in reality eats most cheap ribbons for breakfast.
Very useable 3.5KHz+ unlike some ribbons.
rgds, sreten.
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@ Godzilla. Yeah those w4-1320 are really little Gems, I like em a lot. And relative cheap 4 for the price of one accuton middriver.
I also have them in small sealed enclosures, but I had them in an OB once and was shocked by the improvement of musicality. Cant remember the xo. But will try it soon again. Hopefully the lower Qts is not a problem.
@ Sreten. A nice curve indeed, (and price). But a curve is not everything.
I have listened to many expensive speakers and shows. I noticed that most of the time I liked the ribbon tweeters very much (of course not all).
Especially the more expensive RAAL drivers.
Like in the Siltech Arabesque speakers: Siltech Cable, Arabesque Speakers, Crystal Cable - YouTube.
Many softdomes are a little slow. I know I like the speed (not bright), for me it makes it more natural (of course with the right balance).
Thanks for the link by the way, for that price a fun tweeter.
On topic; Would the A&D R1524 in a H frame go as low as a Eminence Beta 15A?
I also have them in small sealed enclosures, but I had them in an OB once and was shocked by the improvement of musicality. Cant remember the xo. But will try it soon again. Hopefully the lower Qts is not a problem.
@ Sreten. A nice curve indeed, (and price). But a curve is not everything.
I have listened to many expensive speakers and shows. I noticed that most of the time I liked the ribbon tweeters very much (of course not all).
Especially the more expensive RAAL drivers.
Like in the Siltech Arabesque speakers: Siltech Cable, Arabesque Speakers, Crystal Cable - YouTube.
Many softdomes are a little slow. I know I like the speed (not bright), for me it makes it more natural (of course with the right balance).
Thanks for the link by the way, for that price a fun tweeter.
On topic; Would the A&D R1524 in a H frame go as low as a Eminence Beta 15A?
a Goldwood GW1858 is decent if you can get it cheap and plays into the low 30's- relatively low moving mass and well controlled - a bit bloated in H-baflle so it may sound better balanced on a small flat baffle. (A dollar US per ounce of ferrite slug used to be enough to buy cheap woofers.)
An externally hosted image should be here but it was not working when we last tested it.
@ Greebster, Sreten. They are on my to buy list, for this or future builds. Thanks again!
Also great for in car build after winter. For now I have the Ribbons already, and will work up from there. Even thinking about AMT Mundorf, I heard the Eton's, but no Mundorf's yet. Indeed AMT's are fine!
Freddi, I didnt think about the 18's for the main speakers yet because of the size. Thought about using 18's in a IB coupled to the double sized room below. But I don't have enough knowledge yet if that would work well with my relative small listening room. Or that 18's in that smaller room in the main speakers (without IB) would get the same results.
I expect the IB will go much lower. For that I do have to use seperate Amps like Godzilla also suggested and EQ them.
Goldwoods are difficult to get in Europe I believe, so I would take Eminence or A&D probably (Beyma are expensive)
Also great for in car build after winter. For now I have the Ribbons already, and will work up from there. Even thinking about AMT Mundorf, I heard the Eton's, but no Mundorf's yet. Indeed AMT's are fine!
Freddi, I didnt think about the 18's for the main speakers yet because of the size. Thought about using 18's in a IB coupled to the double sized room below. But I don't have enough knowledge yet if that would work well with my relative small listening room. Or that 18's in that smaller room in the main speakers (without IB) would get the same results.
I expect the IB will go much lower. For that I do have to use seperate Amps like Godzilla also suggested and EQ them.
Goldwoods are difficult to get in Europe I believe, so I would take Eminence or A&D probably (Beyma are expensive)
Actually you get 6dB more. Compared to one woofer doubling the area gives 3dB boost. Then series connection drops voltage sensitivity 3dB so +3dB -3dB = 0dB, same sensitivity as one woofer. With parallel connection you get +3dB voltage sensitivity so total is +3dB from doubling woofer area and another +3dB from increased voltage sensitivity = +6dB.
If one Beta-15A is around 90dB in dipole (this depens a little of baffle width, Mr. Corkscrew's baffle is wider than just the woofers) then two in parallel are around 96dB but of course your amp needs to feed 4ohm without problems. Not neccessary the case with all few-watt tube amps.
Anyway, Beta-12CX might be a nice companion to pair of Beta-15A's... The sensitivity of that coaxial should be just enough.
Don`t say this on public forums unless you`re desperate for a quick price adjustment
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