Probably, but won't it also depend on the crossover and the amount of phase shift? No issue with timing so far. No smeared transients. But the woofers are still changing so time will tell.
The boxes were built like this to allow for changing the baffle to accommodate different hf drivers. Just change the baffle boards rather than the full front panel.
The boxes were built like this to allow for changing the baffle to accommodate different hf drivers. Just change the baffle boards rather than the full front panel.
Troels recently posted a speaker that actually used this type of setup to time align the drivers. The bass and mid-range were on the same plane with the tweeter set back. One advantage was that it allowed him to chamfer the baffle surrounding the mid-range which should improve diffraction. Dave has largely exploited this technique and has taken it one step further with his new MarKen T. Thanks again for the effort that we will all benefit from.
http://www.troelsgravesen.dk/Jenzen-SEAS-ER.htm
http://www.troelsgravesen.dk/Jenzen-SEAS-ER.htm
Thiel has been doing that for as long as I can remember. But as this is only a test system, I'm still free to create a baffle with the tweeter set back from the mid. With a low crossover point the wavelength is long enough that the woofer / mid crossover is mostly pretty much a non-event from a timing perspective.
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If Bill is XOing them at 160 Hz then a 1/4 wl is almost 19". Time alignment is a non-issue as configured.
dave
There's as much snake oil regarding speaker design as there is real science. It's not all THAT difficult with the modern modeling tools There's also the experience factor and just plain ol common sense. Sticking to sealed boxes makes it easy and, at least for me, ends up with IMHO better results.
That said, the enclosures on Dave's planet 10 site are really advanced and NOT derived from reduced snake oil.
That said, the enclosures on Dave's planet 10 site are really advanced and NOT derived from reduced snake oil.
If I had to do it over again (and I probably will build a few more of these), I'd make the opening to the sub-enclosure narrower so that a narrower sub-baffle could be used. As it is, the sub-baffle has to be as wide as the primary baffle so that it can be firmly attached.
And for this particular design, a box 48" high and 18" deep would perform very closely to this 48" high 24" deep box.
Attachments
Sorry for the lack of recent reports. There is a LOT going on and there just isn't enough time to go around right now. Testing will probably resume over the weekend since there is definitely light at the end of the tunnel. Maybe.
I can report that the 830668 does integrate very well with a number of different drivers. A single driver realistically needs 60+ liters but NOT more than 120 liters unless the box is to be "packed" with UltraTouch recycled denim (absolutely the best box stuffing solution). And I mean packed as in over-packed. F3 on single driver systems is ~ 33hz - 38hz give or take. Using dual driver systems (2 x 830668 in each cabinet) with a LARGE choke (= or > 12.mH) on the lower driver and a typical crossover point on the upper driver, there's a pleasant deep bass hump around 40hz - 60hz with F3 will be below 30hz with F10 well below 20hz. I can only measure to 20hz and it's only down about 4hz in room. But this solution needs a fairly efficient full-range driver to keep up with the woofers unless the system is bi-amped with level controls,
There does not seem to be audible or measurable driver break-up when using the woofers in a range suitable for use with a full-range driver (< 500hz). Even when the 830668 is run full range, driver break-up is mildly audible but not bad at around 2500hz, far above what would expected when being used with a full-range speaker.
I might be able to post some crossover combinations in late January (after CES / T.H.E. Show) when I get my hands on a few Mark Audio drivers. (Donations for testing welcome. )
In conclusion, the Peerless 830668 is a driver worth considering for bass reinforcement under a high-quality full-range speaker.
More details later when there's time to develop a good crossover. Or two. Or three.
I can report that the 830668 does integrate very well with a number of different drivers. A single driver realistically needs 60+ liters but NOT more than 120 liters unless the box is to be "packed" with UltraTouch recycled denim (absolutely the best box stuffing solution). And I mean packed as in over-packed. F3 on single driver systems is ~ 33hz - 38hz give or take. Using dual driver systems (2 x 830668 in each cabinet) with a LARGE choke (= or > 12.mH) on the lower driver and a typical crossover point on the upper driver, there's a pleasant deep bass hump around 40hz - 60hz with F3 will be below 30hz with F10 well below 20hz. I can only measure to 20hz and it's only down about 4hz in room. But this solution needs a fairly efficient full-range driver to keep up with the woofers unless the system is bi-amped with level controls,
There does not seem to be audible or measurable driver break-up when using the woofers in a range suitable for use with a full-range driver (< 500hz). Even when the 830668 is run full range, driver break-up is mildly audible but not bad at around 2500hz, far above what would expected when being used with a full-range speaker.
I might be able to post some crossover combinations in late January (after CES / T.H.E. Show) when I get my hands on a few Mark Audio drivers. (Donations for testing welcome.
)In conclusion, the Peerless 830668 is a driver worth considering for bass reinforcement under a high-quality full-range speaker.
More details later when there's time to develop a good crossover. Or two. Or three.
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Yes!, Good to hear you'll try the SB. Looking forward to your thoughts on that one.
Have you considered: http://www.solen.ca/pdf/dayton/DA270-8.pdf
Bad metal breakup, but you're crossing very low. Ugly too, imo. Not a bad price though, and very obtainable.
Have you considered: http://www.solen.ca/pdf/dayton/DA270-8.pdf
Bad metal breakup, but you're crossing very low. Ugly too, imo. Not a bad price though, and very obtainable.
I have limited time and cabinet resources. I can look at a few drivers and driver combinations but won't be doing a lot of testing. But maybe a few others can try a few promising drivers to let us know their results. I just happen to be working of a different project that required testing the 830668 in a couple of different configurations so I thought it might be helpful to the members of this forum.
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I can also report that the Scan Speak 25W8565 (either -0 or -1) will work well in roughly the same cabinets as the Peerless 830668. They will provide a little deeper bass by a few hz, but cost a LOT more. My personal preference is the Peerless. It will be a much better match for the CHR-70, Alpair 7.3 or 10.2.
I would recommend the dual woofer set-up for the 10.2 since it is a more efficient driver and will better match sensitivities. Bi-amping with level controls on the amps can equalize the sensitivities if that option is available.
I would recommend the dual woofer set-up for the 10.2 since it is a more efficient driver and will better match sensitivities. Bi-amping with level controls on the amps can equalize the sensitivities if that option is available.
The 10.2 could handle a low XO such as 60hz at that point a 12" woofer would sound pretty good. You could get down to the 20's and integration would be less difficult. Just watch out, some of those plate amps have built in delays. Mine measured 4 ms off! That will really throw you off if you are trying to integrate it by distance.
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Too many options, not enough time build 'em all, or post about all that we do complete
You might well get away with crossing the 7.3s even lower than 200Hz, but the question of how to go about the XO is always tricky - depending on the relative sensitivity of drivers, cost of passive components for such filter points can approach those of one of the drivers. Enter active bi-amping
Would this be for music only - and if so what sources/amplifier type - or for a multi-channel or PC based system? Those questions relate to the manner / ease with which the XO can be achieved and adjusted to suit driver / room situation.
I'm using a quasi-FAST approach with the MA A7.2: A while ago I purchased from P10 Mar-Ken deci size cabinets that had the second gen A7s in them and they sound great all by themselves. But wanting a little more punch and heft I then constructed two woofer boxes (basically 11sq" cubes) and put the SDX7s into them, sealed and stuffed.
Hold your collective noses, audiophiles, but I'm using a dbx proaudio active crossover...cheap and fairly effective. Playing around w/ crossover frequencies I found what for me is the sweet spot at about 150-160hz. The super-steep 24db/octave slope doesn't allow much "blend" between drivers near the xover frequencies, but from further than near-field listening it is VERY impressive...great woofer with lots of punch and little annoying boom.
The woofers are driven by the little PE dta-100 which has great hold on the woofers, the A7s by an old version of the Decware Taboo, a pentode design w/ about 6w/ch.
One of these days I'll explore passive crossover possibilities but for now the proaudio solution rocks!
Mario
Hold your collective noses, audiophiles, but I'm using a dbx proaudio active crossover...cheap and fairly effective. Playing around w/ crossover frequencies I found what for me is the sweet spot at about 150-160hz. The super-steep 24db/octave slope doesn't allow much "blend" between drivers near the xover frequencies, but from further than near-field listening it is VERY impressive...great woofer with lots of punch and little annoying boom.
The woofers are driven by the little PE dta-100 which has great hold on the woofers, the A7s by an old version of the Decware Taboo, a pentode design w/ about 6w/ch.
One of these days I'll explore passive crossover possibilities but for now the proaudio solution rocks!
Mario
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