IDK.
I decided not to tune my 15"+CD box for 30 hz (organ pipes, Low A of piano 26 hz) because there might be a big dip between resonance F3 and where the woofer starts falling off at 100 hz in test wall. I will build another 15" box if I want to hear that low. I have 75 W mono amps I picked up for $20 to $45 right after the burglar took everything musical. I picked up an electronic crossover for $50 which has a 12 db roll off for the sub & mains, adjustable knob for frequency 16 to 200 hz. From the guy I bought the SP2(2004)s from.
Pro speakers are often arrayed, so arranging multiples side by side with angled sides can form an arc which represents part of a theoretical point source. Used on their own, the cabinet shape at the back is not likely to make such a fundamental difference to directivity.
Peavey says that it reduces standing waves. That's also what damping material is for. What remains can be rearranged by angling sides but standing waves can still be formed by such a shape.
Well, the link in post 15 covered putting wedge shaped cabinets side by side in the bad old days. IMHO interference effects of wall to wall cabinets could push the mid-range horizontal dispersion of that array down to about 10 degrees. When I see SP5 or SP2 in the movies or on TV, two are on stands and spaced at least 2 m apart and usually on opposite sides of the stage. Not stacked side by side.
I do know that SP2 (1985) SP2-XT (1998) and SP2(2004) had approximately the same 2 drivers. 1985 crossed at 800 hz, with 175 watt rating. 1998 crossed at 1200 hz, 350 watt rating. Both were rectangular cabinet. 2004 crossed at 1800 hz, where everybody warns me of the dreadful beaming effect of 15" woofers. SP2(2004) is wedge shaped, and still has a 90 degree 6 db horizontal dispersion spec. 2004 has 500 watt rating.
If Mountainmanbob is intending to cross at 1200 hz, the trouble of bulding a trapezoidal box would not be necessary. He may not even want 90 degree horizontal dispersion. I heard these on stage and decided I liked it.
Reason I'm building 2 ways, Peavey products have pawn shop value and I lost about 20 Peavey units 9/20 to a burglar. Home built products like my AX6/ST120 amp, he left in place. I still live in the city near apartment dwellers. Flea markets are still everywhere. I intend to make my home built 2 way speakers as ugly as possible. Maybe I'll keep them.
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I was planning of putting a 2” layer of this on the back panel and call it a day, and yes it does take up some volume (20-30% in my estimate) but its calculated in. https://www.acoustimac.com/roxul-rb...bxMoSVGFc1TBG7Toh7hCVeK2XUTGhlgAaArX-EALw_wcB.
Pair of N151-M will be here Monday 😎
And no, I don’t want 90deg horizontals! Front wall is only 14’ wide x 30’ long
Pair of N151-M will be here Monday 😎
And no, I don’t want 90deg horizontals! Front wall is only 14’ wide x 30’ long
@indianajo looking back here, are you talking 90deg off axis for 180deg coverage or 45deg off axis for 90deg coverage?
I will be aiming for 45deg off axis to match the waveguide, If I’ve been confused I apologize.
I will be aiming for 45deg off axis to match the waveguide, If I’ve been confused I apologize.
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SP2(2004) 45 deg off axis is only 6 db down from 54 hz to 17 khz. Vertical dispersion +10 deg, -30 deg from horizontal. So built to be mounted on poles. Which is where I mounted them in my music room. That room is 14' wide, 11' tall, 30' long. Pretty dead from furniture, instruments, book & record shelves.
So like you said (in a slightly elongated way) its only a problem with higher low pass. 😉
While researching the econowave I came across someone who rebuilt a pro sound trapezoidal box……might be interesting to find an old empty set of boxes with close to the same volume as mine just to compare measurements, probably get them for next to nothing at the pawn shops. https://projectgallery.parts-express.com/speaker-projects/econowave-15pro/
While researching the econowave I came across someone who rebuilt a pro sound trapezoidal box……might be interesting to find an old empty set of boxes with close to the same volume as mine just to compare measurements, probably get them for next to nothing at the pawn shops. https://projectgallery.parts-express.com/speaker-projects/econowave-15pro/
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Just noticed the 15fh500 are gone from the ‘specials’ page at Madisound………I may have gotten the last two!
Was going to maybe get two more if I liked them……oh well. 😕
I’d have to really, really like them to pay full retail.
Was going to maybe get two more if I liked them……oh well. 😕
I’d have to really, really like them to pay full retail.
I bought a pair a couple of months ago.
They are sitting on the rack out in the garage.
You have me interested, I will run the TS/P with impedance sweep on them to see how they look out of the box.
Thanks DT
They are sitting on the rack out in the garage.
You have me interested, I will run the TS/P with impedance sweep on them to see how they look out of the box.
Thanks DT
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DT, just looking at them in the packing (I don’t want to take the banding off until starting) they look very well built but the cast aluminum is very thin and has a pronounced bell like ring when tapped……might go the extra mile and hit the basket (spokes) with strands of plumbers putty.
I don't like how thin the basket is on these specific Faital drivers either. They definitely ring and don't look like they are thick enough to be acoustically inert. Some stamped frame drivers are better than these in that regard ie the Dayton PA310. Still a good deal for what they normally go for, which IMO isn't worth it.
Some manufacturers use a 12db/octave for the tweeter and 18 for the woofer. This is supposed to make a 3rd order filter for both because of the natural roll-off of the horn. I tried it and it appears to work, but I don’t have golden ears and I rarely push a lot of power into my Econowaves even though they can take hundreds of watts.
Thanks Arthur, more than likely going to try a few different crossover approaches, including dsp.
Could you go into more detail about yours (or provide a link if you’ve already documented it)?
@profiguy , I reckon the PA380 would be the comparable in this case, and to tell you the truth it looks pretty nice! (Except a kindly high Le of 4.12)
I’ve used the 10” PA255-8 and really love it (above 60hz) especially its smooth but articulate mids.
Could you go into more detail about yours (or provide a link if you’ve already documented it)?
@profiguy , I reckon the PA380 would be the comparable in this case, and to tell you the truth it looks pretty nice! (Except a kindly high Le of 4.12)
I’ve used the 10” PA255-8 and really love it (above 60hz) especially its smooth but articulate mids.
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Yeah, I should have pointed out my comparison of drivers was based on the best stamped basket thickness to driver size ratio. The PA310 was the driver that stood out to me from previous builds. The PA380 is a bit flimsier IMO. I would compare to the Faital 15HF500 in regards to basket integrity and design, which doesn't say much for a cast frame driver.
Another thing to consider regarding basket integrity is how much mounting the driver to a baffle plays a role in damping the basket. I believe Faital is trying to go for the least amount of weight for a given size driver. They probably didn't design that series of driver for hifi use specifically. Its like comparing a cargo van with a luxury SUV - they both can carry stuff, but one does it more comfortably than the other.
Nothing some putty or roof cement won’t fix……the design looks quite inflexible/strong just rings like a dang school bell!
If you mass (pre) load them as part of the cab bracing as Dave p10 does, you 'kill' a bunch of driver construction 'shortcomings' in one 'shot'.
Here is a link to a paper by Pi Speakers which is probably where I got the idea. I think it’s worth reading even if you don’t use the design, lots of good info in this paper.
Also, I got it backwards, sorry, it’s second order on the woofer and third order on the tweeter.
https://www.pispeakers.com/Speaker_Crossover.pdf
The pioneers originally did it best; they mounted the driver to a massive framed structure anchored to the floor and the the baffle/box was just 'floated'/set over it with a leather or rubber inner tube 'gasket' to seal it. True woofers were built with its field coil power supply in a floor mounted casting for lag bolting to the floor.