Pearl Acoustic Sibelius

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#846
chrisb said:
Did you ever try using the room modelling tools in REW to assist in aligning multiple subs? So far I’ve only played with two in the front wall corners, and the alignment routine recommended at a minor delay( .3ms, IIRC). I’ve been toying with the idea of building small vented boxes for a pair of Fosgate Audiophile subs I’ve not used in over 10 years, but that’d mean running more cabling or opting for wireless transmitters for the rear pair.
Since I’m picking your brain, any experience or observations on mixing sealed and ported in the same room, when miniDSP is available? I’ve always preferred sealed, but the car subs don’t model in WinISD as particularly happy with that alignment. I don’t have the budget for a quad of SVS SB16 Ultras😵
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I’ve used a mix of ported and sealed…..but never implemented DSP in those instances. Not that improvements could not be had, just the performance was satisfying enough with just plop and play and some gain adjustments. That’s the beauty of multiple subs…..they kinda take care of everything on their own.

Think of your room as a closed body of water or wave pool. One wave generator makes rollers that build into peaks. Add a second and you get the same size waves, just more of em. Add a third and the waves become more numerous but the crests as significantly smaller……then add a fourth and it’s pretty much even turbulence throughout. Ported systems can work to your advantage here with each port being its own wave generator.

Now as to 4 SVS ultras ……i‘m by no means a basshead…..so for me, 4 sealed high excursion 8” subs in a reasonable size room is often enough. With room gain and DSP, an F3 in the mid 20hz range is typical in room response. Of course where bass is concerned bigger is always better ( sans the fast bass nonsense). We’ve got 4 12’s in our family room ( only because we could instead of should lol) and that’s enough to get a call from the neighbor and I’m constantly fixing popped drywall nails in there. That system uses 2x4 DSP and Crown amps at 600wpc. The cost of that sub system was less than $2k……it would leave a pair of Ultras in the dust.
 
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#847
acko said:
Thanks Dave and Scott, look forward to the new plans. A quick question: what sonic benefits of the Pensils vs say a much smaller sealed box like this, since Fb around same order:
https://www.markaudio.com/wp-conten...00-M-Bessel-aligned-sealed-box-standmount.png
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Difficult to compare meaningfully since Fb alone doesn't tell you much, especially between dissimilar box types. A Bessel aligned sealed box begins its [shallow] initial rolloff relatively high up, and has the fastest possible settling time from an inpulse, with a small overshoot. The Pensil, as a hybrid between a trad. pre-T/S high-gain reflex and a trad. TL has a user-variable alignment by design, but as default, tracks a classic quasi pro-audio alignment with broadband gain for approximately 1.5 octaves above Fb and a damped 3rd order initial rolloff (eventually increasing to 4th order like all vented systems), with a relatively resistive impedance load -not flat-line but less reactive than most vented systems.
 
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#850
planet10 said:
Thanx for that mp9, it was full of information beyond a review of the lousdpeaker.

It really makes one appreciate the rich world of diy we live in.

dave
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Yes. Remember when we didn't have internet. Back then it was much more difficult to find DIY. But there were good drivers at that time too. Now there are all the possibilities to build very good speakers.
The fact that there are good designs created by Scott and Dave makes it possible to get the best out of these drivers.
 
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#851
Dave, at least, along with many, many others. I certainly wouldn't put myself in that category, or even remotely near. But yes: the 'net, for all its issues, has been a great liberator of information, and it makes it much easier for people to create quality speakers in our little corner of the world, along with many other things. From my POV, we're all of us standing on the shoulders of giants -and there are some still with us, whether from the depth of their knowledge & willingness to share with others, their ability to produce hardware, software or components, or in many other ways.
 
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#853
Hello all !

I've read the entire thread twice and i cant seem to find direct answer..

If I would use MAOP 10 driver instead of Alpair, would it be better or simply a little different ?
If anyone has tried this, yes I have seen the youtube video with this setup but no information for comparison...


If the outside dimensions were a bit different, bigger size (because I have raw oak boards 50mm thick, about 45mm would be finished), keeping the inside dimensions entirely and I would round the corners with oval shape roundover, dont know proper terms sorry, but its not simple radius. The idea for roundover would be to lessen difraction.


Any thoughts for this ?

Thanks!
 
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#856
I have this bit, approx. 16mm would be on face and back, about 32mm on the sides.

Gotta be super careful tho, its a huge bit, so far not used heh...
 

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#857
@Dario123
That's the idea. And, yes, you'd have to be very careful. You don't want to engage that sharp outer blade edge and gouge the front baffle.
But my thought was that the roundover would start gently -- the largest radius section closest to the drivers -- and the small radius portion 'round the corner of the baffle... like the old Thiel loudspeakers.
 
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