I want the subwoofer to be able to loudly and cleanly reproduce 20 Hz at 115 dB at 10 feet for playing pipe organ music and the deep rumbles in dark ambient music. I also would like decently tight and powerful drum hits in goth-industrial and rock music. The room is about 30 x 30 x 30 feet on concrete slab (main room in a Bucky geo dome home).
The plan:
I'm thinking I want to have lots of large drivers and power to keep distortion low. I'm thinking cone excursion should be kept to a minimum. But to get volume with low excursion, I need lots of piston area. To keep the motion tightly controlled, a sealed box, good sized voice coils, with a good effective damping factor from the amp/speaker wires.
Eight 18 inch drivers total in two separate enclosures. Four per sub wired in parallel for 2 ohms per channel. The Dayton's are cheap and look like they might be about right:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-085
The amp is a Crown MA-3600vz wired to a 30 amp 120 volt circuit, so I should have 1800 watts per channel at 2 ohms or 3600 watts total. The amp will be about 20 feet from the subs. Based on the following page I should use some big wire to improve damping factor. I'm thinking 4/0 welding cable:
http://www.bcae1.com/dampfact.htm
http://store.weldingdepot.com/cgi/weldingdepot/R0040x.html
The plan is to drive the amp using my Echo (Event) Layla rack mount PC sound card with two of the channels driven off a custom low pass filter and multiband parametric eq I'm making using Synthedit, Audiomulch, and some VST plugins. The low end rolloff will be compensated/tweaked with the parametric.
The main speakers are Magneplaner MG 3.6 amped off a Crown MA-2400 hooked to the Layla.
I'm not very experienced in speaker design/building. I used WinISD to try to design a sealed enclosure. I've come up with 42 x 38 x 21 inches (LxWxH) for the internal dimensions (19.3 cubic feet) for each sub. The two will be placed end to end so it'll be like a 44 x 78 inch, 23 inch high coffee table. Four speakers will be on the left/right sides, and 4 more on the front/back sides. The enclosures will be braced 1 inch MDF, with polyfill stuffing.
I'm unclear about the Qtc of a sealed design and its effect. Some threads and pages have suggested .71 (my dimensions above with the 18 inch Daytons). Others say for deep bass, use lower, like .5. According to WinISD I get slightly more SPL using a larger box and lower Qtc. I've thought about using higher vmax 15 inch drivers in the same size enclosure to get a lower Qtc. But my previous experience with sealed enclosures (car stereo project) showed me having more total piston area and less excursion would give deeper cleaner bass than having less piston area but more excursion with the same size enclosure. And WinISD does show the 18s being a few dB higher in output than 15s in the same size box. And my hunch is that the distortion at 20 Hz from the 18s will be less since there's less cone motion. The transient response would be better with 15s (assuming similar motor as the 18s). But I think I'm more interested in clean massaging bass than drum kicks, so I'm leaning toward the 18s.
I haven't bought any drivers or MDF yet and would appreciate comments by others who've built high powered sealed enclosure subs. Like is my basic plan reasonable? What other brand drivers would be good? 15s or 18s? Larger box?
The plan:
I'm thinking I want to have lots of large drivers and power to keep distortion low. I'm thinking cone excursion should be kept to a minimum. But to get volume with low excursion, I need lots of piston area. To keep the motion tightly controlled, a sealed box, good sized voice coils, with a good effective damping factor from the amp/speaker wires.
Eight 18 inch drivers total in two separate enclosures. Four per sub wired in parallel for 2 ohms per channel. The Dayton's are cheap and look like they might be about right:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-085
The amp is a Crown MA-3600vz wired to a 30 amp 120 volt circuit, so I should have 1800 watts per channel at 2 ohms or 3600 watts total. The amp will be about 20 feet from the subs. Based on the following page I should use some big wire to improve damping factor. I'm thinking 4/0 welding cable:
http://www.bcae1.com/dampfact.htm
http://store.weldingdepot.com/cgi/weldingdepot/R0040x.html
The plan is to drive the amp using my Echo (Event) Layla rack mount PC sound card with two of the channels driven off a custom low pass filter and multiband parametric eq I'm making using Synthedit, Audiomulch, and some VST plugins. The low end rolloff will be compensated/tweaked with the parametric.
The main speakers are Magneplaner MG 3.6 amped off a Crown MA-2400 hooked to the Layla.
I'm not very experienced in speaker design/building. I used WinISD to try to design a sealed enclosure. I've come up with 42 x 38 x 21 inches (LxWxH) for the internal dimensions (19.3 cubic feet) for each sub. The two will be placed end to end so it'll be like a 44 x 78 inch, 23 inch high coffee table. Four speakers will be on the left/right sides, and 4 more on the front/back sides. The enclosures will be braced 1 inch MDF, with polyfill stuffing.
I'm unclear about the Qtc of a sealed design and its effect. Some threads and pages have suggested .71 (my dimensions above with the 18 inch Daytons). Others say for deep bass, use lower, like .5. According to WinISD I get slightly more SPL using a larger box and lower Qtc. I've thought about using higher vmax 15 inch drivers in the same size enclosure to get a lower Qtc. But my previous experience with sealed enclosures (car stereo project) showed me having more total piston area and less excursion would give deeper cleaner bass than having less piston area but more excursion with the same size enclosure. And WinISD does show the 18s being a few dB higher in output than 15s in the same size box. And my hunch is that the distortion at 20 Hz from the 18s will be less since there's less cone motion. The transient response would be better with 15s (assuming similar motor as the 18s). But I think I'm more interested in clean massaging bass than drum kicks, so I'm leaning toward the 18s.
I haven't bought any drivers or MDF yet and would appreciate comments by others who've built high powered sealed enclosure subs. Like is my basic plan reasonable? What other brand drivers would be good? 15s or 18s? Larger box?
With cabs that size and a big room I think you'd be much better off with a bass horn or two. I'm thinking a pair of Jensen Imperial Horn cabs as subs and mains too if you use a 15" subdriver and a 15" coaxial, OR a pair of Labhorns with mouth extenders for sub only duty. A horn is definitely your best bet for high output low distortion bass and you won't need much power or a bunch of drivers.
If I had the room, I'd build the Jensen Imperials and use them for mains and subs. Check out www.decware.com and look in the support forum for a ton of info about them. It's an old design, but a classic and not too difficult a build especially with a helper.
Note that your square room is going to be a real modal problem, so plan on some good bass traps and notch filters to get the optimum sound in those low frequencies.
If I had the room, I'd build the Jensen Imperials and use them for mains and subs. Check out www.decware.com and look in the support forum for a ton of info about them. It's an old design, but a classic and not too difficult a build especially with a helper.
Note that your square room is going to be a real modal problem, so plan on some good bass traps and notch filters to get the optimum sound in those low frequencies.
JMO but using high efficiency 18" pro drivers
with only 6mm of Xmax is not the way to go.
A 15" with 20mm :
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-420
Cheaper but still 15mm :
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-190
Note that 8 drivers will be 9dB more efficient
than one so the 15's will be ~ 98dB/W midband.
sreten.
with only 6mm of Xmax is not the way to go.
A 15" with 20mm :
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-420
Cheaper but still 15mm :
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-190
Note that 8 drivers will be 9dB more efficient
than one so the 15's will be ~ 98dB/W midband.
sreten.
Did you say a coffee table? it would have to be very heavy and braced like the Golden Gate bridge! or else you wont have any cups that will stay on the top with out being rattled off! but i have heard some Rel subs that can double as tables and honestly i think there better off againts a wall or close to a corner,IMO, in the middle of a room is not ideal for extra bass unless its firing down wards and even then, your to close to it to get the best effect. I could be wrong, there are some many factors, but a high X max woofer is needed in any case, 18's are better fo PA, not in a home audio system, a 15 is about your wack!
To mirror some other replies you're on the wrong track. The best that the driver will do is an F3 of 35Hz in a 7.5 cu ft VB; that gives a 1w/1m SPL of 72dB at 20 Hz, so even eight of them will give a sensitivity of 84dB/1watt/1 meter at 20 Hz and you're going to need well over three thousand watts to meet your 115dB/10 ft goal- one which, I might add, is way overkill for any home environment. That kind of power at that frequency is adequate to reduce your home to rubble. That, plus the total required box volume of 60 cu ft makes the project less than feasible.
Different drivers won't help, as higher efficiency drivers will also have a higher F3 and lower F3 drivers will have a lower SPL. The kind of power you want requires a horn loaded system, and the LAB is probably your best bet. Realistically speaking you should also consider scaling back the SPL requirement by at least 10dB, which will still leave it well above THX specs.
Different drivers won't help, as higher efficiency drivers will also have a higher F3 and lower F3 drivers will have a lower SPL. The kind of power you want requires a horn loaded system, and the LAB is probably your best bet. Realistically speaking you should also consider scaling back the SPL requirement by at least 10dB, which will still leave it well above THX specs.
I've been quite busy with my job and haven't had time to read the comments until now. Thanks everyone!
I hope standing waves aren't an issue as the room opens up to the upper level which is totally open. The diameter of the house is 45 feet with a 28 foot peak.
The goal is to have the sub(s) be semi-asthetically pleasing (girlfriend already thinks I have a screw loose..) and not take up too much space in the wrong places. Subs to the side are no go as there is no room (Maggies and other stuff are there). Poor efficiency is ok as I have 3600 watts available for the sub. What I want is low distortion massaging bass below 50 Hz reasonably matched with the 115 dB levels the Maggies can put out. 4 Velodyne HGS-15X are a bit out of my price range. Efficiency be damned. Ebayed Crowns and electricity are cheap!
Folded horns I originally found out about because one large night club I like uses a few walls of large ones (hooked to 100,000 watts of Crowns stacked 3 columns wide to the ceiling
, earplugs are a must!), but they take up way too much space, and group delay problems with them keep coming up in my google searches. Granted they're very efficient but my room is relatively small and low distortion with massaging frequencies is my goal.
I normally listen at 70 to 90 dB. I specified 115 dB at 20 Hz because I figured if it sounds clean at that level, it'll sound really damn clean at 80.
I dunno.. maybe I should go with some higher excursion 15s. The box would be smaller certainly. But my TLAR thinking is the sound comes from only the driver in a sealed enclosure, and that more driver area moving less should be better than less driver area moving more. The movement is non-linear right? Which means it's more linear the less it moves. More linear is better right? And if the resonance frequency is high, it shouldn't matter because I have sufficient power and it's a sealed enclosure so I can eq it to sound right.
Worst case, I can always have chainsaw fun and a bonfire out back and start over with a different enclosure....
And if I ever become rich, a bunch of Velodynes.
Side notes:
I fully admit I have no clue other than TLAR, WinISD, and Google (which indicates that high power sealed multiple driver subs in the home are rare (I had no luck finding anything)), and everyone's actual experience is most important to me.
TLAR = That Looks About Right
I hope standing waves aren't an issue as the room opens up to the upper level which is totally open. The diameter of the house is 45 feet with a 28 foot peak.
The goal is to have the sub(s) be semi-asthetically pleasing (girlfriend already thinks I have a screw loose..) and not take up too much space in the wrong places. Subs to the side are no go as there is no room (Maggies and other stuff are there). Poor efficiency is ok as I have 3600 watts available for the sub. What I want is low distortion massaging bass below 50 Hz reasonably matched with the 115 dB levels the Maggies can put out. 4 Velodyne HGS-15X are a bit out of my price range. Efficiency be damned. Ebayed Crowns and electricity are cheap!
Folded horns I originally found out about because one large night club I like uses a few walls of large ones (hooked to 100,000 watts of Crowns stacked 3 columns wide to the ceiling
, earplugs are a must!), but they take up way too much space, and group delay problems with them keep coming up in my google searches. Granted they're very efficient but my room is relatively small and low distortion with massaging frequencies is my goal.I normally listen at 70 to 90 dB. I specified 115 dB at 20 Hz because I figured if it sounds clean at that level, it'll sound really damn clean at 80.
I dunno.. maybe I should go with some higher excursion 15s. The box would be smaller certainly. But my TLAR thinking is the sound comes from only the driver in a sealed enclosure, and that more driver area moving less should be better than less driver area moving more. The movement is non-linear right? Which means it's more linear the less it moves. More linear is better right? And if the resonance frequency is high, it shouldn't matter because I have sufficient power and it's a sealed enclosure so I can eq it to sound right.
Worst case, I can always have chainsaw fun and a bonfire out back and start over with a different enclosure....
And if I ever become rich, a bunch of Velodynes.
Side notes:
I fully admit I have no clue other than TLAR, WinISD, and Google (which indicates that high power sealed multiple driver subs in the home are rare (I had no luck finding anything)), and everyone's actual experience is most important to me.
TLAR = That Looks About Right
Sixthofmay said:
IMHO it sounds like you plan to hammer on a square peg with a jackhammer to make it fit the round hole. Why big power and big EQ to overcome the high Fs of a driver not intended for sub duty when there are plenty of good drivers for all budgets that are intended for that duty? Yes, high excursion contributes to distortion, but it's only one aspect of various design considerations. Linkwitz has some good guidelines:
http://www.linkwitzlab.com/x-thor-measmt.htm
For large SPL in a large room such as you have, horns are without equal IMO. If you own your own space, you can build them in to your room - start to think about placing the horn in the floor or ceiling space if you have it. A horn such as the lab horn gives you high efficiency but compromises have been made and the main advantage it has over a well designed sealed sub is output and efficiency.
The parts express 18" subs are probably not the best to look at given their xmax. However, I think with the idea of larger drivers not needing as much xmax you may be on the right track. I believe PA drivers such as these, although better with a little more xmax, can work very well as subs, however they are normally used in horns or vented alignments and they are not actually quite so efficienct below 50 Hz. The closer you get to 20 Hz the less relevant the nominal sensitivity of the speaker becomes. PA drivers due to their size need to control a smaller cone movement and it is easier to maintain control and thus achieve lower distortion. Can't say I have seen data but apparently they tend to be lower distortion.
Adrian Macks 18" subwoofer might be a better choice with a high excursion PA woofer
This is a very well documented subwoofer design using JBL's 15" driver
I think you have probably stated an inflated target SPL level. A system sounds best within its limits, but you don't need to design for 115 db if you really prefer 90 db. Yes, design it to handle more than you need, but not to the extend that you have to choose a different design to get a level of output that you don't want anyway ....
I doubt you actually get 115 db. Suppose that is at 1m.
@ 2 m distance that will drop probably -6 db ~ 109 db
4m ---> 103 db
6m ---> 100 db
Now this is played to its limits. Turn it down a little so your system sounds its best at something more like 90 db at your seating position (which I'm guessing given a 10m room).
One interesting option would be to place a pair of stereo subs either side of you seating position, say a pair of Dayton Titanics Mk III in sealed boxes. Delay is required of course but you end up not needing massive boxes and the ratio of the direct and reverberant sound field is altered such that you hear more direct sound, and less of the room signature.
If you like velodynes, then consider a DIY alternative that has been compared on distortion:
Critical Q sub based on the Peerless 12" XLS driver
With such a high ceiling, you have many options. You may find that a very tall but relatively slender sub is an elegant solution. Consider unfolding a design such as the lab horn. Mount the two drivers in push pull configuration as this will cancel out even order harmonic distortion. I have seen a website (can't remember where it was) where a design like this was used in a church and they measured 120 db in their auditorium. You could also try this with a TL.
Another thought - your maggies will play louder and cleaner if they don't have to handle down to 50 Hz. You could match their dipole radiation with dynamic drivers used as dipole woofers mounted under your maggies, then cross to a single tall horn sub with a pair of high quality low distortion drivers. You have many options but I'd consider this to be the best of them all.
Here's an example of the dipole
The parts express 18" subs are probably not the best to look at given their xmax. However, I think with the idea of larger drivers not needing as much xmax you may be on the right track. I believe PA drivers such as these, although better with a little more xmax, can work very well as subs, however they are normally used in horns or vented alignments and they are not actually quite so efficienct below 50 Hz. The closer you get to 20 Hz the less relevant the nominal sensitivity of the speaker becomes. PA drivers due to their size need to control a smaller cone movement and it is easier to maintain control and thus achieve lower distortion. Can't say I have seen data but apparently they tend to be lower distortion.
Adrian Macks 18" subwoofer might be a better choice with a high excursion PA woofer
This is a very well documented subwoofer design using JBL's 15" driver
I think you have probably stated an inflated target SPL level. A system sounds best within its limits, but you don't need to design for 115 db if you really prefer 90 db. Yes, design it to handle more than you need, but not to the extend that you have to choose a different design to get a level of output that you don't want anyway ....
I doubt you actually get 115 db. Suppose that is at 1m.
@ 2 m distance that will drop probably -6 db ~ 109 db
4m ---> 103 db
6m ---> 100 db
Now this is played to its limits. Turn it down a little so your system sounds its best at something more like 90 db at your seating position (which I'm guessing given a 10m room).
One interesting option would be to place a pair of stereo subs either side of you seating position, say a pair of Dayton Titanics Mk III in sealed boxes. Delay is required of course but you end up not needing massive boxes and the ratio of the direct and reverberant sound field is altered such that you hear more direct sound, and less of the room signature.
If you like velodynes, then consider a DIY alternative that has been compared on distortion:
Critical Q sub based on the Peerless 12" XLS driver
With such a high ceiling, you have many options. You may find that a very tall but relatively slender sub is an elegant solution. Consider unfolding a design such as the lab horn. Mount the two drivers in push pull configuration as this will cancel out even order harmonic distortion. I have seen a website (can't remember where it was) where a design like this was used in a church and they measured 120 db in their auditorium. You could also try this with a TL.
Another thought - your maggies will play louder and cleaner if they don't have to handle down to 50 Hz. You could match their dipole radiation with dynamic drivers used as dipole woofers mounted under your maggies, then cross to a single tall horn sub with a pair of high quality low distortion drivers. You have many options but I'd consider this to be the best of them all.
An externally hosted image should be here but it was not working when we last tested it.
Here's an example of the dipole
Are you into def car audio by any chance?
I always hear car audio people talk about 160 plus dB and i just give them a blank stare
, what do you say to that ?
115db is a lot of energy, thats a rock concert level am sure, its good short term but its very very bad for your hearing long term, So i would advise against such attempts for your ears longevity, who wants to be that def old man not me for sure, At 1 meter you can get any dB you want but we typically sit 3 to 6 metres away, Speech is around 70-80 dB at three odd feet away, and only few get up into 90 dB, we all know somebody who can do that!
, now 120dB is respect by everyone as the most we can take for a short time and it gets right in your ear hole and hurts after that, 115db is a bit sick, its nice to have a feeling its loud and clear but honestly you dont need to go mental with all these subs, i dont suppose you have heard the grand utopias, You could make yourself a clone and keep your Missy happy also, I have to say your room is massive! thats a task filling that with 115 db in any book, with quality sound. Good luck.
I always hear car audio people talk about 160 plus dB and i just give them a blank stare
, what do you say to that ?115db is a lot of energy, thats a rock concert level am sure, its good short term but its very very bad for your hearing long term, So i would advise against such attempts for your ears longevity, who wants to be that def old man
not me for sure, At 1 meter you can get any dB you want but we typically sit 3 to 6 metres away, Speech is around 70-80 dB at three odd feet away, and only few get up into 90 dB, we all know somebody who can do that! , now 120dB is respect by everyone as the most we can take for a short time and it gets right in your ear hole and hurts after that, 115db is a bit sick, its nice to have a feeling its loud and clear but honestly you dont need to go mental with all these subs, i dont suppose you have heard the grand utopias, You could make yourself a clone and keep your Missy happy also, I have to say your room is massive! thats a task filling that with 115 db in any book, with quality sound. Good luck.Agreed-115dB is unreasonable
Accept this from one who's job is to monitor sound levels at a 6,000 seat arena: you just don't need that kind of power and won't be able to use it if you can get it. 105dB is more than adequate and is in fact the level we are limited to at the FOH in live performance. Understood that you'd like to be able to reproduce pipe organ at actual performance levels; 105dB will put you a good 5dB louder than any pipe organ is able to produce at 20Hz with the possible exception of Westminster, and your house isn't quite that large.
Accept this from one who's job is to monitor sound levels at a 6,000 seat arena: you just don't need that kind of power and won't be able to use it if you can get it. 105dB is more than adequate and is in fact the level we are limited to at the FOH in live performance. Understood that you'd like to be able to reproduce pipe organ at actual performance levels; 105dB will put you a good 5dB louder than any pipe organ is able to produce at 20Hz with the possible exception of Westminster, and your house isn't quite that large.
Hi sies de maio,
I'm wondering about your planning department here. This coffee table sounds like it would knock the bubbles out of a glass of champagne rather quickly. Not to mention tickle the girls bottoms. If the WAF is a concern have you thought about building this stuff into your walls, floors, ceilings?
Just wondering.
Cal
I'm wondering about your planning department here. This coffee table sounds like it would knock the bubbles out of a glass of champagne rather quickly. Not to mention tickle the girls bottoms. If the WAF is a concern have you thought about building this stuff into your walls, floors, ceilings?
Just wondering.
Cal
If you are going to go sealed have a look at Adire's Maelstrom (you will need fewer) and if a coffee table drivers should be mounted rigidly push-push and out of plywood.
As stated a number of times a horn would yield better results but the difference in building and design skill vrs sealed is a HUGE gap...
And don't let the siren song of more power get you... everytime you halve the impedance you typically double the distortion... and in this case start sucking the wall dry.
dave
planet10/always wanted to build and live in a geodesic dome (i built a 47 ft one once, covered in poly -- took us less than a day)
As stated a number of times a horn would yield better results but the difference in building and design skill vrs sealed is a HUGE gap...
And don't let the siren song of more power get you... everytime you halve the impedance you typically double the distortion... and in this case start sucking the wall dry.
dave
planet10/always wanted to build and live in a geodesic dome (i built a 47 ft one once, covered in poly -- took us less than a day)
Dont encourage this chap! Hes on the path to trouble! 52mm excursion in an 18 inch driver is pure nasty~jjdche said:
planet10 said:
Absaulomont! more power is more heat more distortion and less quality, you wanted a crisp clear bass, so getting the best enclosure for the task is your best bet, Your not in compitition with a neighbour by any chance?
Ok some sanity has come back to my head...
Thanks to Sreten for this link to a Dayton high xmax 15 inch sub driver:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-420
Impedance is 4 ohms and will get me to 2 ohms with 2 drivers on each sub channel. And the power rating is close to what I need- 3200 watts for 4 drivers total on the 3600 watt amp should be a decent match as long as I don't go nuts on the volume. Distortion at 2 ohms should low as the amp (Crown 3600vz) was designed with loads like this in mind. And 4/0 gauge wire should give a decent damping factor even though the subs will be about 20 feet from the amp.
I'm aiming for a critically damped Q of .5 based on one of the links posted by Paul. Which comes out to a box size per sub of about 18 cubic feet with stuffing (sealed box). Big but doable in the space I have. I'm going to use lots of bracing in the enclosures too. I chose a sealed box rather than a horn or ported design because, well I don't have much of a clue and this seems the design I can mess up the least..
I'm going to place my order for parts soon and will post some pics of the project. Thanks everyone for the help!!!
Thanks to Sreten for this link to a Dayton high xmax 15 inch sub driver:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-420
Impedance is 4 ohms and will get me to 2 ohms with 2 drivers on each sub channel. And the power rating is close to what I need- 3200 watts for 4 drivers total on the 3600 watt amp should be a decent match as long as I don't go nuts on the volume. Distortion at 2 ohms should low as the amp (Crown 3600vz) was designed with loads like this in mind. And 4/0 gauge wire should give a decent damping factor even though the subs will be about 20 feet from the amp.
I'm aiming for a critically damped Q of .5 based on one of the links posted by Paul. Which comes out to a box size per sub of about 18 cubic feet with stuffing (sealed box). Big but doable in the space I have. I'm going to use lots of bracing in the enclosures too. I chose a sealed box rather than a horn or ported design because, well I don't have much of a clue and this seems the design I can mess up the least..
I'm going to place my order for parts soon and will post some pics of the project. Thanks everyone for the help!!!
IMO a Q of 0.5 is a ludicrous target for a driver with Q = 0.38.
Q = 0.5 needs 140% of Vas per driver which IMO is poor.
Q=0.6 only needs 70% of Vas per driver (half the size) and
the response is barely different, ~ 1dB at 20Hz, piffling.
Note Q = 0.6 = ~ perfect phase and time behaviour.
sreten.
Q = 0.5 needs 140% of Vas per driver which IMO is poor.
Q=0.6 only needs 70% of Vas per driver (half the size) and
the response is barely different, ~ 1dB at 20Hz, piffling.
Note Q = 0.6 = ~ perfect phase and time behaviour.
sreten.
Sixthofmay said:
I'd be wiring them in series to get the best sound out of the amp. You are only getting 1500 watts out of the wall socket anyway, and the amp isn't 100% efficient, so 1000 watts/8/4/2 ohms (and that is probably optimistic) is as much power as you are going to get anyway.
dave
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