In an infinite baffle the Alpair 10 starts to roll off at 200 Hz. There is no way you are going to get an Alpair 10 flat below 200 Hz in any kind of dipole.
Martin
Why not look at TangBand W8-1808 it has an X-max to produce decent bass. I would consider doing EQ in the digital domain with something like Mini-DSP. Put a steep rumble filter at 40 Hz and EQ bass flat to 60 Hz would be possible with W8-1808 achieving something like 90 - 95 dB. Baffle size will not really be critical, placing the unit closer to floor will help bass level.
/Erling
/Erling
Thanks everyone for your input, very much appreciated, I've been reading a lot 
As I can see my requirements are very difficult to meet (at least at our current technological level), I just thought of an alternative idea: a wide-range bass/mid driver, augmented with a super-tweeter crossing over somewhere between 8-14kHz. Unlike the LF crossover, there's no need to worry about feeding the full-range speaker with signal that is beyond its operating limits (ie. too high freq.), so we can leave it crossover-free. And if we could only find a wide response bass-mid driver that naturally rolls-off at roughly 6dB/octave, the entire equation could then be solved with a single small capacitor on the super-tweeter.
What do you think?
@planet10 - I would very much like to try your modified B200s. I understand they can be made in quite a variety of colours? The looks of my audio gear matter to me, not just the sound, and from what I've read, your treatment does wonders to improve both
How big a room needs to be in order to properly accommodate a well-sized B200 baffle?
As I can see my requirements are very difficult to meet (at least at our current technological level
), I just thought of an alternative idea: a wide-range bass/mid driver, augmented with a super-tweeter crossing over somewhere between 8-14kHz. Unlike the LF crossover, there's no need to worry about feeding the full-range speaker with signal that is beyond its operating limits (ie. too high freq.), so we can leave it crossover-free. And if we could only find a wide response bass-mid driver that naturally rolls-off at roughly 6dB/octave, the entire equation could then be solved with a single small capacitor on the super-tweeter.What do you think?
@planet10 - I would very much like to try your modified B200s. I understand they can be made in quite a variety of colours? The looks of my audio gear matter to me, not just the sound, and from what I've read, your treatment does wonders to improve both
How big a room needs to be in order to properly accommodate a well-sized B200 baffle?
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There was a good discussion of this driver recently: Beta 12lta. With a Qts of .5 it's not ideal for your project, but it could work with a large enough baffle. Since you want to go with out any crossover on the fullrange driver I do think the idea of using a BIG fullranger with a super tweeter makes sense.
Joe
Joe
@planet10 - I would very much like to try your modified B200s. I understand they can be made in quite a variety of colours? The looks of my audio gear matter to me, not just the sound, and from what I've read, your treatment does wonders to improve both
How big a room needs to be in order to properly accommodate a well-sized B200 baffle?
The reason i mentioned it is that once in place the owner might well be ameniable to auditions. I can let him know about your interest. They are still a ways to completion.
Only the white cones (mostly Fostex) can have their cone colours changed, Cones that start out dark typically go to black. Spot colours can be varied. I have found that the metal cones (in various colours) seem to look best with spots similar in colour to the cones,
Examples can be seen here: http://www.diyaudio.com/forums/planet-10-hifi/166518-its-not-easy-being-green-apologies-kermit.html
The B200 OBs i had were about 1.3m wide by 1.1m tall. where they had to be placed they impinged on the equipment rack, and ate up too much floor space. Having to quickly swap speakers finding room to shunt them away was problematic. They now reside hanging upside down in the shop (12' ceiling)
Here with Omnes 8 (before treatment -- sort of a low budget Visaton)
dave
Too bad you can't re-paint black cones
Anyway, what do you think of these:
Ciare CH250
Audio Nirvana Super 15 Cast Frame
Anyway, what do you think of these:
Ciare CH250
Audio Nirvana Super 15 Cast Frame
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I don't know if this is going to be terribly helpful at this late stage of the discussion, but here goes.
I built an open baffle pair with some vintage Oval Isophon Alnico drivers as the main midrange units. I am running them fullrange. These are the type with paper concertina surrounds and they were designed to run in open backed radios - so there are few issues with overdriving them.
I cross over a little Isophon tweeter at about 10Khz with a simple cap and some padding down. Fine.
For the bass I didn't want to do the bigger is best solution - whereby you run 15" bass drivers open backed and crossed over at about 400hz. The baffles are just 16" wide. So I put a 10inch bass driver (Isophon again) into an aperiodic box and crossed them over with a simple second order crossover.
Overall result is the best speaker I have built. The bass integration isn't quite perfect, but this is only noticeable on certain radio programs, and with music it sounds just fine.
So my suggestion for keeping an OB reasonably sized is to add a Aperiodic bass helper.
Shoog
I built an open baffle pair with some vintage Oval Isophon Alnico drivers as the main midrange units. I am running them fullrange. These are the type with paper concertina surrounds and they were designed to run in open backed radios - so there are few issues with overdriving them.
I cross over a little Isophon tweeter at about 10Khz with a simple cap and some padding down. Fine.
For the bass I didn't want to do the bigger is best solution - whereby you run 15" bass drivers open backed and crossed over at about 400hz. The baffles are just 16" wide. So I put a 10inch bass driver (Isophon again) into an aperiodic box and crossed them over with a simple second order crossover.
Overall result is the best speaker I have built. The bass integration isn't quite perfect, but this is only noticeable on certain radio programs, and with music it sounds just fine.
So my suggestion for keeping an OB reasonably sized is to add a Aperiodic bass helper.
Shoog
No none at all. These old Isophon drivers are lovely sounding and can almost do it all without any help - so I have always gone the uncrossed over and super tweeter path.
Its the aperiodic approach which I think is novel and has huge potential to both keep the bass tight and detailed - but on a small footprint.
These are the sort of drivers I mean;
http://cgi.ebay.co.uk/Isophon-Fullr...pt=Vintage_Electronics_R2&hash=item5adfbbee82
Shoog
Its the aperiodic approach which I think is novel and has huge potential to both keep the bass tight and detailed - but on a small footprint.
These are the sort of drivers I mean;
http://cgi.ebay.co.uk/Isophon-Fullr...pt=Vintage_Electronics_R2&hash=item5adfbbee82
Shoog
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I was going to suggest the AN15 full rangers... they should do fine on OB without help down below. As a bonus, they are pretty phenomenal drivers with the best sound I've heard. The AN15s are pretty expensive though... well, for me anyway.
At the burning amp meet this year, NP brought some large open baffles with the new Seas full ranger mounted in them. No support for bass and it did ok. There is a thread here somewhere about them.
At the burning amp meet this year, NP brought some large open baffles with the new Seas full ranger mounted in them. No support for bass and it did ok. There is a thread here somewhere about them.
Ciare CH-250 was one of the elements to trigger the going OB wave some 7-8 years ago. Like the Visaton B200 it has a shouting 2-3 kHz range that probably will annoy you if left unattended. You will get response down to 60 Hz on a 1 x 1 meter baffle. My first OB DIY baffle was with CH-250 and had those measures although some of it was two assymetrically sized wings on piano hinges.
I still will suggest digital EQ to master the unit. The German Hobby HiFi had a construction 'Dacapo' dipole which among others: Strassacker: Lautsprecher - Boxen - Selbstbau has components for, look under Hobby HiFi.
The other German DIY paper Klang & Ton had in nr 5 2009 a TQWT construction with the element also with two significant notchfilters to tame the frequencies. This magazine used to downloadable via this link: Lloxx: Heft-Downloads but it seems however at least temporarily down.
DIY Forum has this thread from 2005: http://www.diyaudio.com/forums/full-range/58750-ciare-250-a.html which perhaps can help a bit. I think that notch filters centered around 2 kHz and 8 kHz will do the trick, at least it did for me. I do think it is a project that will pay off in the end, element properly EQed.
/Erling
I still will suggest digital EQ to master the unit. The German Hobby HiFi had a construction 'Dacapo' dipole which among others: Strassacker: Lautsprecher - Boxen - Selbstbau has components for, look under Hobby HiFi.
The other German DIY paper Klang & Ton had in nr 5 2009 a TQWT construction with the element also with two significant notchfilters to tame the frequencies. This magazine used to downloadable via this link: Lloxx: Heft-Downloads but it seems however at least temporarily down.
DIY Forum has this thread from 2005: http://www.diyaudio.com/forums/full-range/58750-ciare-250-a.html which perhaps can help a bit. I think that notch filters centered around 2 kHz and 8 kHz will do the trick, at least it did for me. I do think it is a project that will pay off in the end, element properly EQed.
/Erling
I thought of another interesting (if a bit complicated) possibility: to augment the fullrange with an Eminence Alpha 15A, driven off a separate amp and crossed over with a PLLXO, while leaving the fullrange and its amp crossover-free. In order to be able to drive both amps with the same signal I could adjust gain a bit on the bass amp (to compensate for XO insertion loss) and it should theoretically work pretty well. I could even cheat a bit and include a "bass junkie switch", which would give extra bass boost by means of further increasing the bass amp gain
Adjusting the crossover should be pretty easy too, with a pot in place of R1.
Also, am I right in thinking that using the second-order PLLXO filter I could make a "variable slope" crossover? So that, for example, frequencies above 60Hz are attenuated at 6dB/oct, and frequencies above 100Hz by 12dB/oct? That could be very helpful in getting bass response right.
Adjusting the crossover should be pretty easy too, with a pot in place of R1.
Also, am I right in thinking that using the second-order PLLXO filter I could make a "variable slope" crossover? So that, for example, frequencies above 60Hz are attenuated at 6dB/oct, and frequencies above 100Hz by 12dB/oct? That could be very helpful in getting bass response right.
I would suggest investing in a MiniDSP. It will open up endless possibilites at very little cost. The amount of time you spend on fudging with PLLXO will more than pay for your investment. When you've settled on a best sounding solution with the MiniDSP, you can always replace it with a PLLXO.
Running the full ranger without a crossover will not stop the driver from trying to produce bass frequencies. This will put the same amount of strain on the full range driver as the case where it is not augmented by a helper woofer. Only difference is here you'll get some bass from the helper woofer. The midrange and top frequencies will suffer though, because of the struggling full range driver.
In any case, you should get started with something... even if it is just a single driver on a baffle. The helper woofer will come once you start listening, but at least you'll have fun along the way.
Running the full ranger without a crossover will not stop the driver from trying to produce bass frequencies. This will put the same amount of strain on the full range driver as the case where it is not augmented by a helper woofer. Only difference is here you'll get some bass from the helper woofer. The midrange and top frequencies will suffer though, because of the struggling full range driver.
In any case, you should get started with something... even if it is just a single driver on a baffle. The helper woofer will come once you start listening, but at least you'll have fun along the way.
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Hear, hear !
Actually the Mini-DSP would probably be indistinguisable from the PLLX or the PLLX would sound worse. And the PLLX would not at all have the precision of the digital unit.
But, for Goods sake, build the CH-250 baffle, just don't make it to small, listen, and then go ahead with adjustments. I really enjoyed my CH-250 baffle and I also brought it to our HiFi Forum DIY-show in Sweden with success.
/Erling
Actually the Mini-DSP would probably be indistinguisable from the PLLX or the PLLX would sound worse. And the PLLX would not at all have the precision of the digital unit.
But, for Goods sake, build the CH-250 baffle, just don't make it to small, listen, and then go ahead with adjustments. I really enjoyed my CH-250 baffle and I also brought it to our HiFi Forum DIY-show in Sweden with success.
/Erling
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It sounds from that thread posted on the Ciare CH-250 that it doesnt produce enough bass, mostly due to the small Xmax of 0.5.
Why dont you try something designed around the OB full range concept? Im pretty new to this and have only heard my Wild Burro Purple speakers, but this other designs are supposed to be better. Isn't there someone else that makes something in the 50$~ range designed with OB in mind?
Why dont you try something designed around the OB full range concept? Im pretty new to this and have only heard my Wild Burro Purple speakers, but this other designs are supposed to be better. Isn't there someone else that makes something in the 50$~ range designed with OB in mind?
Ok, ok, enough theoritising - I'll just order the speakers Will let you know of my progress.
As to
Will let you know of my progress.As to
I agree that MiniDSP is wonderfully flexible and considering its price, it's a bargain of a century. In fact, I'm considering buying a few for use in my car and Home Theatre HiFi. But my main system is built so that there is nothing unnecessary getting in the way of the "essence" of music. To put things into perspective: a single MiniDSP (the smallest version) has more components than my entire DAC, pre, amp and both speakers combined... So please don't take it against me if I choose two TX2575 resistors and two Mundorf caps over what is pretty much an entire miniature computer(!). And the price will work out the about the same.
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