The mass corner is defined as 2fs/Qt, above this the power output starts to roll off at 6db. per octave when horn loaded.
For your drivers this occurs at too low a frequency.
There are midbass drivers especially made for horn loading, that have mass corners in the 750Hz. region and rising frequency response above this, these can go flat to a few kHz.
rcw
For your drivers this occurs at too low a frequency.
There are midbass drivers especially made for horn loading, that have mass corners in the 750Hz. region and rising frequency response above this, these can go flat to a few kHz.
rcw
One option would be to re-box your Delta 12's and add another pair. I recently built 4 of the Eighteen Sound trap boxes with P.Audio WN12"s and a Selenium D-2500Ti with a "econowave" style passive crossover. The results are very good.
Running a pair each side gives a wide coverage as the boxes bunch up better.
Eighteen Sound Kits
They are very easy to make as long as you have a means to do angle cuts.
Edit: just realised, there is a "econowave" style crossover for the Delta 12 with a Selenium D220 and the clone JBL PT waveguide (Dayton Dayton Audio H6512) on our photo gallery:
col.
Running a pair each side gives a wide coverage as the boxes bunch up better.
Eighteen Sound Kits
They are very easy to make as long as you have a means to do angle cuts.
Edit: just realised, there is a "econowave" style crossover for the Delta 12 with a Selenium D220 and the clone JBL PT waveguide (Dayton Dayton Audio H6512) on our photo gallery:
col.
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sorry i havent been active in this convo, i had been away for the weekend.
col, just wondering, would i get better out put from one cab with 2x12 drivers, or two cabs each with 1x12 ???
i was at at wedding and noticed the DJ had only one 15 inch active cab. it sounded nice at lower levels and got loud enough on its own to have a good dancing session.
regarding what drivers to use for mid/tops, if i was to bother with buying more deltas, would i be better off upsizing instead? running something like the HD15 cabs off the speakerplans forum just for outright kick/punch ? it would certainly take a load off the deltas.
right this minute, im first going to get an active XO. after having some discussion via PM, i think its imperative i get one of those first. then the next step is more drivers, as my amps arent maxing out yet, i still have room to breathe there. it was also suggested to get DSP/compressors too. so as at this point i have zero knowledge about those, ill best be doing some research.
col, just wondering, would i get better out put from one cab with 2x12 drivers, or two cabs each with 1x12 ???
i was at at wedding and noticed the DJ had only one 15 inch active cab. it sounded nice at lower levels and got loud enough on its own to have a good dancing session.
regarding what drivers to use for mid/tops, if i was to bother with buying more deltas, would i be better off upsizing instead? running something like the HD15 cabs off the speakerplans forum just for outright kick/punch ? it would certainly take a load off the deltas.
right this minute, im first going to get an active XO. after having some discussion via PM, i think its imperative i get one of those first. then the next step is more drivers, as my amps arent maxing out yet, i still have room to breathe there. it was also suggested to get DSP/compressors too. so as at this point i have zero knowledge about those, ill best be doing some research.
I don't think it will make much difference to max output if you run 2 x 12" drivers or two cabs with 1x12". The good thing though, is that it keeps the system more modular and flexible for different configurations, for example with a 4in x 8out xover if you need or want you can run your rig in quadraphonic. Some electronic music producers working with Ableton Live are increasingly using this "quad panning" now.
Using 15"s in mid-high requires exceptionally good 1" or 2" comp drivers as the cone break up on the 15" happens at a lower frequency so usually you have to cross out of them sooner. Most 15" top boxes Iv'e heard have sounded terrible in comparison to a good 12", when used with a sub (not stand-alone). There are some exceptions but usually very expensive 15"s like the powered QSC or powered JBLs.
Using 15"s in mid-high requires exceptionally good 1" or 2" comp drivers as the cone break up on the 15" happens at a lower frequency so usually you have to cross out of them sooner. Most 15" top boxes Iv'e heard have sounded terrible in comparison to a good 12", when used with a sub (not stand-alone). There are some exceptions but usually very expensive 15"s like the powered QSC or powered JBLs.
you just gave me confirmation, kinda, in a round-a-bout way, i think what ill do, is ill keep my deltas as they are. they truly sound fantastic im not complaining about that.
what ill do, ill definately get myself an active XO. that i think will be the beginning of the path to true epic.
after that, the next speaker upgrade i think will be a quad of HD15 cabs. keeping it all modular.
i think doing it like that will keep me the opportunity to use just my deltas, or, deltas and HD15, or delta, HD215 and SS15 combos for any sized gigs. or, as you said, Modular.
any suggestions or opinion on that?
what ill do, ill definately get myself an active XO. that i think will be the beginning of the path to true epic.
after that, the next speaker upgrade i think will be a quad of HD15 cabs. keeping it all modular.
i think doing it like that will keep me the opportunity to use just my deltas, or, deltas and HD15, or delta, HD215 and SS15 combos for any sized gigs. or, as you said, Modular.
any suggestions or opinion on that?
Guys thanks for all the input. Ive been playing with hornresp and discovered that my delta specs are wrong. So i fixed that and also went looking for hd15 and lascala HR specs. And without uploading response graphs coz my internet is capped 
i ran comparisons through sealed then reflex then HD15 then Lascala. And out of the four, my reflex sims the quietest of all. Folled by sealed then hd15 with the LS being the loudest. The hd15 gives bass down to about 85-90hz where the LS drops off at about 110-120 but with an active XO i think the LS cabs are definately the way to go for replacing my reflex cabs as full range. And also could add a third component in there in the form of a pair of 3" drivers for high mid frequencies.
Im pretty excited to get the ball rolling on this before nye. But first things first will be an active XO for sure.
i ran comparisons through sealed then reflex then HD15 then Lascala. And out of the four, my reflex sims the quietest of all. Folled by sealed then hd15 with the LS being the loudest. The hd15 gives bass down to about 85-90hz where the LS drops off at about 110-120 but with an active XO i think the LS cabs are definately the way to go for replacing my reflex cabs as full range. And also could add a third component in there in the form of a pair of 3" drivers for high mid frequencies.Im pretty excited to get the ball rolling on this before nye. But first things first will be an active XO for sure.
You can find an article I wrote about them here....Satellites and Subwoofers
You can also compliance scale other drivers into these alignments.
What the group II ones do is to maximise excursion limited power handling so that the full voice coil and excursion limited power handling can be used.
In a 40 litre box the 12a reaches its rated 2.5mm. cone excursion with an f3 in the 100Hz. region and produces 120db. with 200 Watts.
In general these boxes can produce the same spl. as a horn in half to a third the volume, two 40 litre 12a boxes for instance will produce as much output as a horn that is at least 160=200litres in volume, they need more power but not that much, because if you use two of them close couples the output and increase by around 6db. in this region.
rcw
You can also compliance scale other drivers into these alignments.
What the group II ones do is to maximise excursion limited power handling so that the full voice coil and excursion limited power handling can be used.
In a 40 litre box the 12a reaches its rated 2.5mm. cone excursion with an f3 in the 100Hz. region and produces 120db. with 200 Watts.
In general these boxes can produce the same spl. as a horn in half to a third the volume, two 40 litre 12a boxes for instance will produce as much output as a horn that is at least 160=200litres in volume, they need more power but not that much, because if you use two of them close couples the output and increase by around 6db. in this region.
rcw
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The sealed cab i simmed in hornresp is 55L and in direct comparison to that the lascala is at least 10db louder than it through most of the useful range. I had a brief read on the alignment you propose but did not understand the maths behind it. Hornresp has proven to be quite acurate in its simulations provided driver data is entered correctly. Hence reassessing my data. Do you agree with the simulations i posted or do you still feel that the sealed cab would provide more outright volume/spl?
The amount of sound you can get from a sealed box is nothing like that from a QB5, the reason is that the power output constant for sealed boxes is fixed at .8-.85 whereas if you look at that for the QB5 II alignments it is considerably more, you can expect it to be in the 30-50 region for a driver that has an f3 twice its free air resonance.
This is an increase in acoustic power for the same cone excursion of some 38 times, the delta 12a has no where near the linear cone excursion needed for a sealed box.
You do get an increase in on axis output with a horn, but its acoustic power output drops off above the drivers mass corner.
rcw
This is an increase in acoustic power for the same cone excursion of some 38 times, the delta 12a has no where near the linear cone excursion needed for a sealed box.
You do get an increase in on axis output with a horn, but its acoustic power output drops off above the drivers mass corner.
rcw
Hi Robert,
Iv'e been reading your article on the ESP website. Very informative, interesting and well wrote.
Iv'e got 4 of these 12" P.Audio E12-250N that I pulled out of a set of sealed mid-highs. Iv'e tried them in a ported 50L and they were not much better. I would like to try and model them for a QB5 II alignment. Problem is My maths suck.
I'm wondering if you know of any software that will calculate a QB5 II enclosure? Looking at WinISD it's a shame that all development stopped as it could have been one of the alignments added to that.
cheers,
col.
Iv'e been reading your article on the ESP website. Very informative, interesting and well wrote.
Iv'e got 4 of these 12" P.Audio E12-250N that I pulled out of a set of sealed mid-highs. Iv'e tried them in a ported 50L and they were not much better. I would like to try and model them for a QB5 II alignment. Problem is My maths suck.
I'm wondering if you know of any software that will calculate a QB5 II enclosure? Looking at WinISD it's a shame that all development stopped as it could have been one of the alignments added to that.
cheers,
col.
The only program I use is winisd.
Just put in the ratio between the drivers fs and the f3 you want, this is given in the tables.
Note that alignments are not chiseled in stone and there is quite a bit of leeway, for instance with that p. audio driver the alignment is close to the f3/fs one at 2.118, needing a Qt = .294.
If you use a 30 litre box tuned to 100Hz. with a filter at 100Hz. with a q=.5
For an input of 250W. the cone excursion is around 1.7mm. max.
rcw
Just put in the ratio between the drivers fs and the f3 you want, this is given in the tables.
Note that alignments are not chiseled in stone and there is quite a bit of leeway, for instance with that p. audio driver the alignment is close to the f3/fs one at 2.118, needing a Qt = .294.
If you use a 30 litre box tuned to 100Hz. with a filter at 100Hz. with a q=.5
For an input of 250W. the cone excursion is around 1.7mm. max.
rcw
Hi Robert,
I'm wondering if we should hive this off into another thread? I think I'm going to give it a go. I played around in WinISD a bit last night and It's still not clear to me what I have to input into WinISD apart from the box volume, tuning frequency and EQ/filter. My inability to make sense of your tables maybe...
I have a 50L box with a adjustable 80mm vent. I could reduce the volume of the box by adding some "bracing", or can I align to the larger volume?
Adjusting the EQ/filter in WinISD doesn't seem to change the modelled response?
cheers,
col.
I'm wondering if we should hive this off into another thread? I think I'm going to give it a go. I played around in WinISD a bit last night and It's still not clear to me what I have to input into WinISD apart from the box volume, tuning frequency and EQ/filter. My inability to make sense of your tables maybe...
I have a 50L box with a adjustable 80mm vent. I could reduce the volume of the box by adding some "bracing", or can I align to the larger volume?
Adjusting the EQ/filter in WinISD doesn't seem to change the modelled response?
cheers,
col.
These are winsid simulations of a 30 litre box tuned to 100Hz...
For an input of 250 Watts the cone excursion is as shown, and the spl over this range is 120db.
The input filter has a q=.5, this is a second order L-R, it can also be done with two capacitors somewhere in the signal chain.
rcw
For an input of 250 Watts the cone excursion is as shown, and the spl over this range is 120db.
The input filter has a q=.5, this is a second order L-R, it can also be done with two capacitors somewhere in the signal chain.
rcw
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just checked HR, the lascala cab with 250w driving the Delta12 makes 130db at around about 150hz, from 150-400hz its making 125db, and then it tapers off above 800hz.
im liking the idea of "focusing" the sound via a "waveguide" or horn path, as generally, off axis isnt important when the axis is focused on the D-floor.
and on a different note, i picked up a Behringer CX2310 active XO yesterday, so once i get the new psu for it, ill be hooking it up asap to see how much difference it will make to my reflex cabs.
going back to HR for a moment, my current cabs simulate at 92db@1w, and the LS sims at 102db@1w, so if 6db is thought of as twice as loud, wouldnt that mean that 10db would be nearly 4x louder??? can someone give me an idea/reference to this please? and, as to wether or not HR in this instance is at least 90% accurate? (because if it is, thats pretty dam good IMO.)
im liking the idea of "focusing" the sound via a "waveguide" or horn path, as generally, off axis isnt important when the axis is focused on the D-floor.
and on a different note, i picked up a Behringer CX2310 active XO yesterday, so once i get the new psu for it, ill be hooking it up asap to see how much difference it will make to my reflex cabs.
going back to HR for a moment, my current cabs simulate at 92db@1w, and the LS sims at 102db@1w, so if 6db is thought of as twice as loud, wouldnt that mean that 10db would be nearly 4x louder??? can someone give me an idea/reference to this please? and, as to wether or not HR in this instance is at least 90% accurate? (because if it is, thats pretty dam good IMO.)
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