Top Shelf,
Adding effectively a Aperiodic filter to the back of the driver probably would lower the F3 point in BR loading. But yes sensitivity would certainly take a hit.
The Mass Loaded Transmission Line uses a Helmholtz like terminus restriction port, or a tappered line to do the same without the efficiency hit.
But interesting input non the less!
Adding effectively a Aperiodic filter to the back of the driver probably would lower the F3 point in BR loading. But yes sensitivity would certainly take a hit.
The Mass Loaded Transmission Line uses a Helmholtz like terminus restriction port, or a tappered line to do the same without the efficiency hit.
But interesting input non the less!
Greets!
When it comes to PA, the pioneers did it best overall IMO by sizing the cab based on the driver's compliance and is still in use today by some plus is used to measure Vas in that ideally it's measured when Fs is raised/lowered by 1.56x depending on whether it's a sealed cab or by adding mass.
This equates to a Vas/1.44 = net Vb and tuned to Fs. Obviously, this is counter to T/S theory, especially WRT high Qt drivers, but where size Vs peak power handling to Fs regardless of Xmax is desired [only limits mid band output where any peaking occurs] it's the only choice I can think of ATM.
With such a large, high power driver the vent needs to be huge, like ~10" [25.4 cm] dia. x 29.5" [75 cm] long to get down to ~18 m/sec [~5%] vent mach, limiting BW to < ~200 Hz unless damped like a TQWT.
Since it's already high Q, even the most extreme VC heating/lossy Le doesn't impact peak power response per se, another plus for a compliance based alignment with a calculated GD of only ~13 ms/1 kW @ Fs/Fb.
GM
GM,
Thanks for all of the different suggestions.
I take it the first paragraph was mainly aimed at sealed/FLH.
The second paragraph I assume is geared towards BR alignments. The norm using T/S specs on a B/R with a driver with an Qts of 0.57 like these Dayton 18's is 2.35 x VAS. So 2.35 x 6.86Ft2 is a huge cab for a single 18.
My current cabs have double 18's with four flared 4" ports. Even with only 5mm Xmax (at the limit) I can hear port chuffing 10Ft away outdoors. Two 4" translates to +/- a single 6" port per 18". So a 10" port might be a little overkill but an 8" port sounds about perfect.
Not to sure on the last comnents, as VC heating will always cause power compression. An 13mS of GD seem very low for a BR sub?
Thanks for all of the different suggestions.
I take it the first paragraph was mainly aimed at sealed/FLH.
The second paragraph I assume is geared towards BR alignments. The norm using T/S specs on a B/R with a driver with an Qts of 0.57 like these Dayton 18's is 2.35 x VAS. So 2.35 x 6.86Ft2 is a huge cab for a single 18.
My current cabs have double 18's with four flared 4" ports. Even with only 5mm Xmax (at the limit) I can hear port chuffing 10Ft away outdoors. Two 4" translates to +/- a single 6" port per 18". So a 10" port might be a little overkill but an 8" port sounds about perfect.
Not to sure on the last comnents, as VC heating will always cause power compression. An 13mS of GD seem very low for a BR sub?
You're welcome!
No, just some background information as to how the Vb = Vas/1.44 came about.
Correct. Yes, well aware T/S specs very large cabs, but can't meet your power handling requirement like the pioneer's can.
Not sure what your point is, I mean HR 'says' this small cab requires a 10" for a low enough vent mach @ Fs=Fb @ 1 kW, which it meets without exceeding Xmax.
Yes, though losses aren't as extreme as in a T/S spec'd. alignment due to the cab's high Q peak, Fs tuning, which offsets it somewhat for a peak power net gain in a smaller bulk.
GM
No, just some background information as to how the Vb = Vas/1.44 came about.
Correct. Yes, well aware T/S specs very large cabs, but can't meet your power handling requirement like the pioneer's can.
Not sure what your point is, I mean HR 'says' this small cab requires a 10" for a low enough vent mach @ Fs=Fb @ 1 kW, which it meets without exceeding Xmax.
Yes, though losses aren't as extreme as in a T/S spec'd. alignment due to the cab's high Q peak, Fs tuning, which offsets it somewhat for a peak power net gain in a smaller bulk.
GM
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GM,
I freely admit you are much more versed & knowledgeable on high efficiency alignments!
So last night I spent a few hours with WinISD Pro-alpha, & ver 7.something. It confirmed my suspicions that in a BR these Dayton's want 10ft^3.
It also supported your suggestion of a really large port C/A. Like your 10" port might be a little small even, kind of surprised me given the low'ish SPL range.
Brian Steel did a quiky model of an isobaric 4th-order BP in HR. 138L with good response & sensitivity. Unfortunately WinISP shows much larger vol required, and generally worse all around performance. A large 14Ft^3 6th-order BP looks good, but the portability in an issue then.
BR at 10Ft^3 Fs at 37.Hz looks good, but some weird impedance spikes (inductive reactance) crops up. 50Hz in particular is funky, massive Ohms minimum excursion and drawing 100Watts while the average power is at 750Watts. Seems if you tuned it as a 50Hz cab the sensitivity is off the charts. Like 128Db at 100Watts amp-load, obviously the amp would be pushing voltage that at 8Ohm = 750+Watts, but the impedance is so high the net wattage would be 100-effective watts.
If what WinISP is showing me is correct, these Dayton's tuned for 50Hz would out perform large FLH at 50Hz (only).
Although my comment about GD was correct, 13mS is not attainable at low tunes with this driver. Surprisingly the 6th BP has half as much as the BR?
I freely admit you are much more versed & knowledgeable on high efficiency alignments!
So last night I spent a few hours with WinISD Pro-alpha, & ver 7.something. It confirmed my suspicions that in a BR these Dayton's want 10ft^3.
It also supported your suggestion of a really large port C/A. Like your 10" port might be a little small even, kind of surprised me given the low'ish SPL range.
Brian Steel did a quiky model of an isobaric 4th-order BP in HR. 138L with good response & sensitivity. Unfortunately WinISP shows much larger vol required, and generally worse all around performance. A large 14Ft^3 6th-order BP looks good, but the portability in an issue then.
BR at 10Ft^3 Fs at 37.Hz looks good, but some weird impedance spikes (inductive reactance) crops up. 50Hz in particular is funky, massive Ohms minimum excursion and drawing 100Watts while the average power is at 750Watts. Seems if you tuned it as a 50Hz cab the sensitivity is off the charts. Like 128Db at 100Watts amp-load, obviously the amp would be pushing voltage that at 8Ohm = 750+Watts, but the impedance is so high the net wattage would be 100-effective watts.
If what WinISP is showing me is correct, these Dayton's tuned for 50Hz would out perform large FLH at 50Hz (only).
Although my comment about GD was correct, 13mS is not attainable at low tunes with this driver. Surprisingly the 6th BP has half as much as the BR?
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djtimmy77,
I assume you got some of the last ones on clearance?
I got four, it was kind of an impulse buy due to the $120 clearance price -Doh. I had totally forgot about the massive upward Qts re-rating on them.
Anyway, large BR seems to be the alignment so far. I've fiddled with WinISD for hours trying to refine the best alignment. Here's what I think I've settled for, its bigger than I wanted but that's how it goes.
SBB4, 10Ft^3, Fs: 37Hz, Port Size 18.5W x 6H x 13.06D".
PWR In: 889.4W/69.3V.
Peak Air velocity: 35.5Hz= 17.8m/s.
I own a Peavey IPR3000DSP & an Crest ProLite3.0DSP, these have four parametric filter bands, up to 8th-order HP/LP's, limiters, Etc.
If each PA465S-8 is fed by a bridged amp (= 120V output swing) little over 2KWatt at impedance minimums (36Hz =7 Ohms, 110Hz = 5.6 Ohms)
Filters:
(1.) HP Butterworth, n=8(8th order), Fc=31Hz.
(2.) LP Butterworth, n=4(4th order), Fc=120Hz.
(3.) Parametric Eq, Fc=35, Q=4, Gain=1.5Db.
(4.) Parametric Eq, Fc=100 Q=4, Gain=2.0Db.
Results per single Cab/Driver:
* NOTE: These results had an average excursion of about 8.5mm, and a max of 12.2mm at 50.5Hz.
35Hz = 124.6Db
40Hz = 126.4Db
60Hz = 126.3Db
70Hz = 126.0Db
80Hz - 95Hz =125.6Db
100Hz =125.4Db
110Hz =123.3Db
Yeah I know it's not TH/FLH output, but I believe WinISP calculates for 2-Pie space, so not totally horrible
If rated 125.5Db average output +/- 1.5Db's, 35-100Hz:
Not accounting for PWR Compression - which member GM seems to think will be less than normal for these drivers (based on the T/S specs)?
Qty: 2 Cabs = 131.5DB's, +/- 1.5Db's, 35-100Hz.
Qty: 4 Cabs = 137.5Db's, +/- 1.5Db's, 35-100Hz.
I believe if 4-Cabs are operated in 1-Pie space that = 143.5Db's
+/- 1.5Db's, 35-100Hz. Which seems inline with DSL gear, at 1/6 the price.
If I need all four cabs for a gig, I'll just remind myself that the combined 40Ft^3 isn't that huge Well at least it'll look impressive.
Lets see what you come up with!
I assume you got some of the last ones on clearance?
I got four, it was kind of an impulse buy due to the $120 clearance price -Doh. I had totally forgot about the massive upward Qts re-rating on them.
Anyway, large BR seems to be the alignment so far. I've fiddled with WinISD for hours trying to refine the best alignment. Here's what I think I've settled for, its bigger than I wanted but that's how it goes.
SBB4, 10Ft^3, Fs: 37Hz, Port Size 18.5W x 6H x 13.06D".
PWR In: 889.4W/69.3V.
Peak Air velocity: 35.5Hz= 17.8m/s.
I own a Peavey IPR3000DSP & an Crest ProLite3.0DSP, these have four parametric filter bands, up to 8th-order HP/LP's, limiters, Etc.
If each PA465S-8 is fed by a bridged amp (= 120V output swing) little over 2KWatt at impedance minimums (36Hz =7 Ohms, 110Hz = 5.6 Ohms)
Filters:
(1.) HP Butterworth, n=8(8th order), Fc=31Hz.
(2.) LP Butterworth, n=4(4th order), Fc=120Hz.
(3.) Parametric Eq, Fc=35, Q=4, Gain=1.5Db.
(4.) Parametric Eq, Fc=100 Q=4, Gain=2.0Db.
Results per single Cab/Driver:
* NOTE: These results had an average excursion of about 8.5mm, and a max of 12.2mm at 50.5Hz.
35Hz = 124.6Db
40Hz = 126.4Db
60Hz = 126.3Db
70Hz = 126.0Db
80Hz - 95Hz =125.6Db
100Hz =125.4Db
110Hz =123.3Db
Yeah I know it's not TH/FLH output, but I believe WinISP calculates for 2-Pie space, so not totally horrible
If rated 125.5Db average output +/- 1.5Db's, 35-100Hz:
Not accounting for PWR Compression - which member GM seems to think will be less than normal for these drivers (based on the T/S specs)?
Qty: 2 Cabs = 131.5DB's, +/- 1.5Db's, 35-100Hz.
Qty: 4 Cabs = 137.5Db's, +/- 1.5Db's, 35-100Hz.
I believe if 4-Cabs are operated in 1-Pie space that = 143.5Db's
+/- 1.5Db's, 35-100Hz. Which seems inline with DSL gear, at 1/6 the price.
If I need all four cabs for a gig, I'll just remind myself that the combined 40Ft^3 isn't that huge
Well at least it'll look impressive.Lets see what you come up with!
Wowza! Great stuff!
I picked up a pair of drivers and used the $25 off st paddys day coupon so they came out to $107.50 each for me!
My use will be the bottom section of some up close and personal DJ monitors. Think extreme budget version of the funktion one floorstanding DJ monitors. I haven't sat back down with hornresp yet but I will say that my initial put was to try and get one box per sheet of plywood, it seems worth it to expand on that limit. 10 cu ft is still way smaller than the FT30 tapped horns I built [4] as my main subs. Hopefully I will finish my thoughs one evening this week and start making sawdust next weekend.
I picked up a pair of drivers and used the $25 off st paddys day coupon so they came out to $107.50 each for me!
My use will be the bottom section of some up close and personal DJ monitors. Think extreme budget version of the funktion one floorstanding DJ monitors. I haven't sat back down with hornresp yet but I will say that my initial put was to try and get one box per sheet of plywood, it seems worth it to expand on that limit. 10 cu ft is still way smaller than the FT30 tapped horns I built [4] as my main subs. Hopefully I will finish my thoughs one evening this week and start making sawdust next weekend.
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djtimmy77,
Wow 18" drivers in near-field monitors, are you halfway going for the visuals?
You must be cranking some serious Db's at your shows.
I dont think I've ever thought to myself - I need more bass at my mix station.
How big are those FT30's?
Are you a solo packout kind of performer (like me), or do typically have roadies. Four beastly subs doesn't sound to fun to move all the time.
Anyway good luck with your monster monitors, and post some pic when you can.
Wow 18" drivers in near-field monitors, are you halfway going for the visuals?
You must be cranking some serious Db's at your shows.
I dont think I've ever thought to myself - I need more bass at my mix station.
How big are those FT30's?
Are you a solo packout kind of performer (like me), or do typically have roadies. Four beastly subs doesn't sound to fun to move all the time.
Anyway good luck with your monster monitors, and post some pic when you can.
Finally revisiting this build. April got busy and then it was too hot in South Florida to build (side yard and garage). Now it is cooling down and I plan on building these speakers the week of Thanksgiving.
Sublimacon, it is a hobby system, so not using it every week. All of the big speakers are on wheels and I won't do anything with stairs, so it isn't terrible.
Sublimacon, it is a hobby system, so not using it every week. All of the big speakers are on wheels and I won't do anything with stairs, so it isn't terrible.
Scrutinizing this Thread...: 
@bjorno,
I typed (on my cell) a long response to your post, but the forum's server timed out- and poof there went that. The two programs produce very different results! I will say - I find it hard to believe that FOUR 1000w 18"s in 40-cubes of cab can only compete with a single Beringer 18 cab?
@djtimmy77,
Can't wait to see some pics of your mega-monitors! Tuning lower than 37Hz actually hurts F3/spl/ pwr handling.
I typed (on my cell) a long response to your post, but the forum's server timed out- and poof there went that. The two programs produce very different results! I will say - I find it hard to believe that FOUR 1000w 18"s in 40-cubes of cab can only compete with a single Beringer 18 cab?
@djtimmy77,
Can't wait to see some pics of your mega-monitors! Tuning lower than 37Hz actually hurts F3/spl/ pwr handling.
I realize WinISP is rather crude compared to Hornresp, but the results seem excessively different! This is a basic BR alignment, the fundamental formulas should be the same in both programs. In particular the impedance plots look very different, hence why the -3db pwr handling/xmax -vs- my models.
My starting point was 35 hz tuning but there was a big bump that I didn't like. These will be close enough to the listener that I can give up a little output for flatter reaponse.
I compared results in hornresp, winisd, and basta, they were close enough to each other that I am good with it. I may make the port in such a manner that I can adjust relatively easily. I got 3 sheets of BB last wednesday so hopefully will be cutting wood today.
I compared results in hornresp, winisd, and basta, they were close enough to each other that I am good with it. I may make the port in such a manner that I can adjust relatively easily. I got 3 sheets of BB last wednesday so hopefully will be cutting wood today.
@ djtimmy77,
Although I totally get a want to be flat to 30Hz for EDM, sacrificing 5Hz on your highpass filter does way more good things to the overall curve. Producing serious spl at =/<30Hz requires lots-O-displacement & pwr, or crazy huge TL's/Horns. If your Amp's have DSP or your running a rack mount PA management unit, check out my suggested settings in post #27. Also if indoors, room responce anomalies most likely will be much worse than that of the subs.
Although I totally get a want to be flat to 30Hz for EDM, sacrificing 5Hz on your highpass filter does way more good things to the overall curve. Producing serious spl at =/<30Hz requires lots-O-displacement & pwr, or crazy huge TL's/Horns. If your Amp's have DSP or your running a rack mount PA management unit, check out my suggested settings in post #27. Also if indoors, room responce anomalies most likely will be much worse than that of the subs.
@ bjorno,
I wanted to say thank you for the amazing amount of sim data you condensed into two pgs! Also, don't take my thread responses as being critical of your efforts. WinISP has been reasonably accurate over the years (for me).
That's why your Hornresp sims seem so underwhelming to me. Not to they are incorrect, but perhaps a few parameters got transposed? I realize these Dayton 18's have sort of weak-sause motors on them, but they can operate with a considerable amount of wattage and have half decent Xmax.
I wanted to say thank you for the amazing amount of sim data you condensed into two pgs! Also, don't take my thread responses as being critical of your efforts. WinISP has been reasonably accurate over the years (for me).
That's why your Hornresp sims seem so underwhelming to me. Not to they are incorrect, but perhaps a few parameters got transposed? I realize these Dayton 18's have sort of weak-sause motors on them, but they can operate with a considerable amount of wattage and have half decent Xmax.
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