Playing around with PS95-8 FAST
Here is a FAST using the Dayton Audio PS95-8 driver in a Nautaloss with trapezoid baffle. XO is 225Hz LR -24dB/oct.
Freq response (grey is no EQ) and XO shape:
Impulse response:
It sounds very nice - the EQ helped to get rid of the sizzle/ringing.
Here is a FAST using the Dayton Audio PS95-8 driver in a Nautaloss with trapezoid baffle. XO is 225Hz LR -24dB/oct.
Freq response (grey is no EQ) and XO shape:
Impulse response:
It sounds very nice - the EQ helped to get rid of the sizzle/ringing.
Attachments
The drivers for the dual 8 inch KaZba are described in an earlier post in this thread: http://www.diyaudio.com/forums/full-range/271011-rockin-kazba-dipole-k-aperture-z-baffle-dipole-4.html#post4254747
$10 buyout units from PE. They are kind of cheap - the surrounds on some are becoming unglued from the cone - nothing a bit of hot melt glue can't fix. But that should not be happening to brand new drivers. Also, the surrounds and cone, and dustcap just have a cheap plasticky feel to them. These do not feel as good as the $5 buyout 6.5 in polycone woofers that I bought previously (same drivers as the ones used in the Dayton B652's). Those were a great deal and had more quality to them. Having said that, the TS parameters advertised are quite accurate. That is, the Qts is in the mid 0.5's and the fs is about right. When put into a KaZba, the bass performance is astonishing (solid 30Hz bass extension in dipole) for $20 worth of drivers.
If you wanted to do this right, and have some money to spend, the Dayton RS225-8 ($57 ea) would be a killer driver to use in a parallel 4-ohm setup for push pull. The 7mm xmax, and 0.38 Qts, with 29Hz fs is ideal. Also, it is a quality unit with great cast frame, copper shorting ring, and stiff aluminum cone. Used in an 18mm BB ply KaZba - would be something to hear.
any 12" (or even 15") candidates? - that might help move some air - what happens if you block one aperture creating sealed back chamber? - imagine not practical but inquiring minds want to know
Perhaps a good candidate for less extreme values of Qt than an Alpha 15A, say Beta 15A or equivalent?
although qt might be a bit too high, Pyle's PPA15 has gotten good marks for open baffle work - it sounds toyish in their cabinets
there should be some relatively inexpensive 12" suitable - maybe PA310-8 http://www.parts-express.com/dayton-audio-pa310-8-12-pro-woofer--295-032
http://www.diyaudio.com/forums/subwoofers/98956-15-bass-driver-ob-40-200hz-6.html#post1297097
http://www.amazon.com/Pyle-15-Inch-...&ie=UTF8&qid=1427691850&sr=1-1&keywords=ppa15
there should be some relatively inexpensive 12" suitable - maybe PA310-8 http://www.parts-express.com/dayton-audio-pa310-8-12-pro-woofer--295-032
http://www.diyaudio.com/forums/subwoofers/98956-15-bass-driver-ob-40-200hz-6.html#post1297097
http://www.amazon.com/Pyle-15-Inch-...&ie=UTF8&qid=1427691850&sr=1-1&keywords=ppa15
The PA310-8 is a nice looking driver with 97dB sensitivity and 5mm xmax with a kick butt motor. It's some coin though not your cheap I don't care if don't work driver anymore. However, I believe the $10 drivers have proven that this concept works and a suitable driver upgrade is in order. I actually have quite a respect for Dayton Audio drivers now. Each one I have tested and used have proven to be high quality, well built, great value, and sounds excellent. RS100's, PS95-8, PA130-8 all great drivers. I expect the PA310 to be just as good.
not your cheap I don't care if don't work driver anymore. However, I believe the $10 drivers have proven that this concept works and a suitable driver upgrade is in order. I actually have quite a respect for Dayton Audio drivers now. Each one I have tested and used have proven to be high quality, well built, great value, and sounds excellent. RS100's, PS95-8, PA130-8 all great drivers. I expect the PA310 to be just as good.
After all my builds and designs so far - this is one that's really surprised me with how simple and effective it is. If you like open baffle dipole but not the huge baffle - this may be the ticket. Cover with grill cloth in front and back and it looks like any other conventional rectangular prism speaker. The OB dipole top doesn't have to be wide at all. In fact, same width as the 12in wide box is a great size for a suitable FAST XO somewhere in the 350Hz range. I think the design I have can have improved upper bandwidth by making it shallower and aperture larger. The ratio of area over volume controls the upper bandwidth falloff. If right now I am at 200Hz and I want 350Hz then I need to decrease depth by 200/350 or about 5 inches total depth. Now this may pose some problems for depth of basket and magnet so we can increase size of aperture say by 50% going up higher and maybe an inch wider on each side to 10in at bottom and the depth can be decreased to about 7in from 9in. OTOH, if you have a fancy shallow basket woofer maybe with Nd magnets this may be just fine. Something cool about a thin speaker too. I really have been a little lazy in modeling this in Akabak and combined with fact I was Akabak-less for almost 2 months did not help. The model will show exactly where the depth and aperture size needs to be set. Anyhow, to achieve 700Hz with the AMT tweeter is asking too much - just need to go no K aperture but keep Z baffle.
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Well it depends on the ratio of the cross sectional area of the aperture to the volume. So a larger driver will have a larger K aperture. So it's very similar to your existing slot loaded woofers that you currently have - they act as band pass devices. In the extreme case one can put a volume filler custom cone body in the volume in the front cone to reduce the volume and increase the bandwidth. So just because you have 18in drivers is not automatically bad. I know that 18in drivers in a push pull opposed geometry slot loaded sub has a limitation though as the minimum slot channel length is 18in plus clearance of 2in for 20in. That is 0.508 meters and the quarter wave resonance is 167Hz so that max upper freq of PPSL force canceling setup is 167Hz. In KaZba I don't think you have this limit.
In the case of a 20cm deep chamber in a KaZba - that is same as 427Hz quarter wave - and it is better because the K aperture makes the hard boundary of the chamber depth less of an issue. This is one reason to have your K aperture go the entire length of the speaker rather than truncated short like how I did it.
In the case of a 20cm deep chamber in a KaZba - that is same as 427Hz quarter wave - and it is better because the K aperture makes the hard boundary of the chamber depth less of an issue. This is one reason to have your K aperture go the entire length of the speaker rather than truncated short like how I did it.
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hi CLS -are you going to use two 18's per channel? I've used an Eminence like Sigma18 - qts was a bit lower at 0.25 and mms 105g. on other K stuff, TheJessMan has to put a clear coat on the little 0.65X K15 for me and they'll be done. Hope they play nice. I asked for something different with dark wings and light shell - hope they look ok to others
http://i.imgur.com/0EXba6P.jpg
http://i.imgur.com/0EXba6P.jpg
Your new box is beautiful. I like the colors.
Your Sigma18 seems not a regular one. Maybe there had been several versions. Mine is 130g Mms and 0.27 Qts. I don't know how the Mms changed after the mods -- several coats of PVA glue on both sides and de-cap. And, the spider is softened by silicon oil. The fs drops from 27Hz stock to 22Hz. And then to 16Hz by slot-loaded (slot of 40% Sd or so).
Your Sigma18 seems not a regular one. Maybe there had been several versions. Mine is 130g Mms and 0.27 Qts. I don't know how the Mms changed after the mods -- several coats of PVA glue on both sides and de-cap. And, the spider is softened by silicon oil. The fs drops from 27Hz stock to 22Hz. And then to 16Hz by slot-loaded (slot of 40% Sd or so).
interesting mods for sure - especially the silicon oil - what product does one look for ? - what sonically do you think was the effect of PVA? - was it the consistency of Modpodge thinned 50/50? - I have another set of thicker (and more straight profile) cone EM18 with mms 130g and fs~23 sold under "Electar"
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On other lighter cones playing higher, PVA coating makes the the sound cleaner, less noisy. But on this big dumb woofer, TBH I can't detect any difference. And I haven't used Modpodge so I don't know how they compare.
Dropped fs does have some effect. It digs deeper indeed, but also hit the 6 mm Xmax sooner. For HT stuff, I have to cut LF below 30Hz.
Dropped fs does have some effect. It digs deeper indeed, but also hit the 6 mm Xmax sooner. For HT stuff, I have to cut LF below 30Hz.
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