Comments on this dipole setup?

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Read articles from Linkwitzlab, Troels, Kreskovsky, Ariel project etc... would this work? What would be best dimension for the enclosure as there is debate going on as to wide baffle or narrow baffle is better...

*****
* W *
*M T*
* W *
*****
* B *
* B *
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T(Tweeter) - Hiquphon OWI or SEAS Excel Millenium or Scanspeak Revelator or D2905/9500

M(Midrange) - Accuton C244-8 or Scanspeak D3806/8200

W(Woofer) - Seas Excel W22 or Audio Technology Flexunits 8 I 52 20 08 SD

B(Bass) - Adire DPL12 or Shiva 15-inch (need bigger box)

Enclosure design:
Similar to Orion open baffle dipole
Midrange and tweeter is placed side by side between 2 woofers with ratio of 1.618 measured from side of baffle
Baffle made of soft wood such as pine, with both sides covered in a layer of damping material (e.g. cork, foam, latex etc.)
Driver holes in baffle are chamfered to allow sound radiation into rear space
Woofers are not attached to baffle but to a rear backbone like the revised Orion design
The rest of speaker is made of marine plywood and braced where necessary.
Base unit housing bass driver is made from double layered marine plywood in a H-frame, the internal of the H-frame is layed with accoustic foam.
Aluminum pipes are cut lengthwise to act as semi circular trimmings around the baffle. The space between the trimming and baffle is filled with damping material.
Whole unit is mounted on a solid metal base with 3 inverted hemispheres to prevent vibration if unit is placed on uneven ground (I prefer it to spikes as it is a chore to move speaker with spikes)
Similar drivers are wired in parallel and as such each box requires 4 channels to function.

For center speaker, just mount the woofer and tweeter as follows on a open soft wood (e.g. pine) baffle with damping layer all over. The woofers are wired in parallel and altogether this requires 2 channel.
*****
*WTW*
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Alternatively, can toy with idea of mounting the center to wall below wall mounted TV as a infinite baffle setup as it looks ugly with a center speaker placed in the middle of the living room, blocking the TV.

The above setup is using a DSP XO/EQ to control the individual drivers. Such DSP speaker control systems are offered by Behringer, DEQX, Rane, DBX, etc... However they require balanced XLR input. As such a converter (e.g. Artisoft Cleanbox) is required to convert the RCA(from preamp or AV amp) to XLR.
The XO/EQ output is amplified using UcD180 to power each channel to the drivers. UcD 400 is employed to power the bass drivers' channel.

For room shattering bass, construct a subwoofer with 2 downward firing ports. The driver to use will be the Adire Tumult 18-inch subwoofer driver mounted facing down. Optmimal port specifications and dimensions for internal volume can be obtained from WinISD. Internal dimensions are built in rations of 1.618. The box is constructed from thick double layered marine plywood and has 3 legs ending in 3 inverted hemispheres. A new idea is to add a 20-inch flat circular dish below the driver that can be raised and lowered via 3 vertical rods attached to the body. The dish will contain some sound damping gel adhered to the inside of the dish surcace. This serves 2 functions. It protects the driver during transport and it can be used to adjust bass response by adjusting the height of the dish. The amplification of the bass driver will be provided by Adire's own XO/EQ/UcD amplifier.

IMO surrounds does not warrant that much of an investment in quality. A reasonably small good full-range or coaxial speaker mounted in one of those tiny commercially available boxes will do. They can be powered by the AV amp powered output.

Other food for thought
There is this taiwanese company that is producing drivers that rivals the quality of some of the hi-end drivers from the more established companies at a substantially reduced cost. Check them out at www.usheraudio.com.tw. Read they are a lot better than the tangbands, also from taiwan... Replacing the tweeter and midband with Usher drivers looks like a good alternative.

The sound of the speakers may sound too "digital" to some ears... Was wondering if there is a way to make it sound more "mellow and warm" like the tube amp sound. Having tube amps for so many channels is crazy... One way may be to use musical fidelity's tube output buffer. Another may be to try ICEPower instead of UcD. Read ICEPower has more "tube like" sound.
 
It depends how much trouble you are prepared to go to to get all that to work optimally. I prefer a couple of woofers for bass duties, a large driver to cover from the woofers to the tweeter, and a helper tweeter.

I am currently playing with a Behringer DEQ2496 and am both impressed with what it can do, and a little disappointed with what it does to the sound. Like all hi-fi, it's a compromise! ;)
 
High Nuuk. I posted your TNT review on the DIY T-amps as a link on a fullrange thread and though to myself.. "hmm, Nuuk didn't say what the Chalize was like in comparison to a good gainclone". So I thought I'd ask here. ..slightly off-topic (..but why not).

sjong47:

I'd change some things.. most notably the line configuration to (top to bottom):
M
T
W
W

With this the "w" midbass drivers will couple better to the floor without suck-out.. additionally with this setup you can have your "w" section wider than your top M-T section. Finally, the horizontal axis of the M-T section will be easier to work with (and that M-T section doesn't mean that the T can't be moved toward one side of the baffle or another for better acoustic centering and less diffraction). The T should be aproximatly at your listening height (typically around 33 inches when normally seated), with the midrange slightly elevated. The subwoofer section should be moveable for better room placement and should NOT be under the main panel.

The drivers are typical hi-fi drivers.. Good, but not exactly excellent. In particular you could do better for the "w" midbass section - which especially in a free-air dipole configuration will sound "gutless" (i.e. lacking in dynamic "drive"). I specifically would NOT pair the Accuton with any of the tweeters you listed. If your stuck on those drivers then by all means choose the scan-speak mid. to acompany one of those tweeters. I'm also not a fan of the Adire drivers. They are good drivers in many respects, but like the other hi-fi drivers mentioned they are of the high mass high excursion school of thought. For the money you would likely be better off with two (or more) of the Dayton RS HiFi 12 inchers for subwoofer duty.

Amplification-wise the Ucd modules sound good provided you have a good power supply and are willing to make some minor modifications (as mentioned in the "hotrodding" thread of the digital amp forum section). But you might want to see what Nuuk has to say about better gainclones.
 
Scott, if I am totally honest, I just prefer the GC in my main system. That may be partly due to the fact that I have separate woofers powered by GC's and it's preferable to match the amps in such circumstances.

I found with a class-T amp for the main drivers, it was hard to match up the woofers (somebdy said the class-T amps change phase with freqeuncy or something like that).

With different speakers I may prefer the Charlize etc! 'Horses for courses' as we say here ;)
 
Nuuk said:
Scott, if I am totally honest, I just prefer the GC in my main system. That may be partly due to the fact that I have separate woofers powered by GC's and it's preferable to match the amps in such circumstances.

I found with a class-T amp for the main drivers, it was hard to match up the woofers (somebdy said the class-T amps change phase with freqeuncy or something like that).

With different speakers I may prefer the Charlize etc! 'Horses for courses' as we say here ;)

Sounds about right to me. ;)

I've mentioned to others that if you want the sound of a high feedback pentode OTL on a serious budget - then the T-amps are your thing.. But if you want something closer to a modest SET with additional freq. extension and impact then a GOOD gainclone is the way to go. (..it will likely never be a substitute for completely a transformer coupled all DHT amp with good transformer cores. On the other hand at 100th+ of the price its not even a comparison.)

Hmm, have you tried current mode operation yet? I think things could get even better when you take the load's back emf out of the equation.
 
Hi Scott,

I am not really well versed with driver compatibility. Care to share some of your insights? What drivers are good with what drivers?

Also you mentioned about bass "suck out" if coupled to the floor... what does it mean?

I'm new to this... so pardon me asking such questions :p

As for the "Excusion school of thought" what is it? What other schols of thought are there? I thought as long as it can produce a decent graph in WinISD from the TS specs with good low freqency response, it is good enough? After all, it is all about trying to make all the drivers to match synergistically to produce a response line as flat as possible... no?
 
Drivers with similar diaphram materials should generally be chosen. I.E. ceramics (accuton) are NOT the same as doped silk (the tweeters).

Though not cheap (while not horribly expensive either) these are the drivers I'd recomend:

Mid: Veravox 5s (..I think this driver is no longer being produced, but it is still available from Solen.ca ..so if you want one you'll need to order it quickly. There are other good midranges available BUT they are more costly and may not work as well with the midbass I've suggested.)
Tweeter: RAAL 140-15D (..the best tweeter I've seen for anywhere near the money, though not cheap.)
Midbass: Supravox 285 GMF (..you will only need one per speaker, though you could double up, and it is perhaps the best driver available at a reasonable cost for this freq. range as a free-air dipole. This driver is VERY dynamic, even as a free-air dipole with a good baffle.)

The "suck-out" problem is an emperical problem, (i.e. most others have found this as a problem), where IF the baffle (for the free-air dipole drivers) does not extend to the floor then the lower midrange and upper bass becomes more attenuated than normal. (generally coupling to a boundry like the floor gives 3db of gain.. but it seems to go beyond this for this application.) This may not be a problem IF you have eq. correction AND you cut-off the lower response dipoles (say around 200 Hz) and run the subwoofers into the midrange (..which I wouldn't suggest unless they are also dipoles). The easiest way to hear this is mounting on a normal baffle that extends to the floor and then lifting it up about a half-foot plus off the floor. When its on the floor - more midbass, when its off the floor - less midbass "i.e.suck-out".

High eff. and low mass for a given sd, with low x-max progressive suspensions that introduce less time based distortion. (i.e. drivers that start AND stop quickly - subjectively described as "fast" drivers.) This usually limits high spl's for a given bandwidth with increasing harmonic distortion as higher spl's are achieved), but at normal listening levels the sound is usually MUCH better. Note that ALL of the drivers I've mentioned above are like this. ..and no, its about FAR more than trying to achieve a flat amplitude on-axis. The sub driver I'd suggest is the BMS 15S430, or the 18S430.

Here are the links:
For the tweeter and the mid. click on their names:
http://www.solen.ca/
additionally:
http://www.raalribbon.com/products_flatfoil_140-15.htm
For the midbass:
http://www.supravox.fr/haut_parleurs/285_GMF.htm
and priceing here:
http://www.audiokit.it/itaeng/Altoparlanti/Supravox/SupraVox.htm
For the subwoofer:
http://www.bmspro.info/index.php?show=item&usbid=10282&id=54386
and priceing here:
http://www.assistanceaudio.com/02_BMScones.html
 
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