Few of the differences between power amps can be perceived with subwoofers. The performance of all subwoofer drivers is vastly inferior to the performance of any half decent amp, to the extent that you need not be concerned. From a performance point of view there are two factors - power and control. The distortion and non linearities of the driver are always far greater than the amp. I believe PA amps tend to have more power and better control of the driver. How this shows up in specs I don't know. I heard a comparison of a Crown K1 amp with a plate amp for a Tempest subwoofer and the Crown was clearly superior - the bass had more authority, and was more full bodied.
If you think you hear any other differences between sub amps, then it's probably your imagination. It would probably not show up in a blind AB test where the listeners don't know what they are hearing.
What makes an amp a "sub amp?" Merely the fact that you are using it for a sub ie. nothing. Mosfet amps are reliable and powerful, this makes them suitable for subs. By all means try out that amp that you have.
Since you don't know what type of amp it is and you don't know how much power it has, what will you actually learn?
There is no reason not to try it. You might be able to look up specs for the amp and if you can find out power handling, it will help you decide how much power you need.
As mentioned above, whether or not it's a mosfet is irrelevant. It would be more relevant for full range use.
If the amp is stable down to 2 ohms, then you may be able to bridge both channels and find out what more power is like. If it handles 2x200w into 8 ohms then you may find bridging will yield as much as 1 x 800w, depending on whether or not it is able to double its power into half the impedance. Configured this way you will see what extra headroom is like, assuming that with 200w, more is desirable.
Don't try this unless you can be sure the amp is up to the task.
If you think you hear any other differences between sub amps, then it's probably your imagination. It would probably not show up in a blind AB test where the listeners don't know what they are hearing.
What makes an amp a "sub amp?" Merely the fact that you are using it for a sub ie. nothing. Mosfet amps are reliable and powerful, this makes them suitable for subs. By all means try out that amp that you have.
Since you don't know what type of amp it is and you don't know how much power it has, what will you actually learn?
There is no reason not to try it. You might be able to look up specs for the amp and if you can find out power handling, it will help you decide how much power you need.
As mentioned above, whether or not it's a mosfet is irrelevant. It would be more relevant for full range use.
If the amp is stable down to 2 ohms, then you may be able to bridge both channels and find out what more power is like. If it handles 2x200w into 8 ohms then you may find bridging will yield as much as 1 x 800w, depending on whether or not it is able to double its power into half the impedance. Configured this way you will see what extra headroom is like, assuming that with 200w, more is desirable.
Don't try this unless you can be sure the amp is up to the task.
I'm searching the forum for input on the peerless xls and came up with pertty general question that takes a couple of steps backward. What do I really want this for? Everyone is used to the questions regarding appropriate use, expectations, etc. Home theater, classical, rock, techno, etc. I've gotten so caught up in the pace of ideas and choices and technical specifics that I kind of forgot where I started out. I began with a 3dAcoustics sub/satellite system in 1979. Unpowered DVC 10" in a vented sub with an audax (polydax) paper coned rubber-suspended six inch and one inch dome in each sat. I was very happy with it for many years. I got sold on the simplicity/sound factor.
I always wanted to diy a higher quality version of it. I want a system for music exclusively - and at very moderate levels at that. No helicopters over the roof, dinosaurs stomping up from the basement.... but the most musically accurate bass possible.
Someone mentioned his distaste for large moving mass, huge magnets, and massive voice coils - but didn't really elaborate on why. I got to thinking.. do most of the dedicated sub drivers out there have built-in tradeoffs in order to be "all purpose"? In other words, if I really want the best driver for music, at moderated listening levels, is something like the XLS, or Shiva, or Titanic, just overkill in the worst way? I want great quality bass for medium room listening. Is this a useful question? Or are these drivers still the best for music of any type?
I apologize for hijacking this thread. I tried to start a new one and was automatically asked to search my topic before I posted it. I thought better of it and just stuck it in here.
I always wanted to diy a higher quality version of it. I want a system for music exclusively - and at very moderate levels at that. No helicopters over the roof, dinosaurs stomping up from the basement.... but the most musically accurate bass possible.
Someone mentioned his distaste for large moving mass, huge magnets, and massive voice coils - but didn't really elaborate on why. I got to thinking.. do most of the dedicated sub drivers out there have built-in tradeoffs in order to be "all purpose"? In other words, if I really want the best driver for music, at moderated listening levels, is something like the XLS, or Shiva, or Titanic, just overkill in the worst way? I want great quality bass for medium room listening. Is this a useful question? Or are these drivers still the best for music of any type?
I apologize for hijacking this thread. I tried to start a new one and was automatically asked to search my topic before I posted it. I thought better of it and just stuck it in here.
Bluebeard,
I suggest two choices:
One, get a sub that's optimised for fidelity over output. Look for a low distortion motor - XBL or a motor with faraday rings etc. Drivers like Adire Koda or Lamda (now supported by AE speakers). Another promising option is Rythmic audio's direct servo kit.
Alternatively consider using bi-amped woofers rather than subs. The big advantage with this that is good for music is you can cross higher than with a sub - say 200 or 300 Hz. The mid driver then can act as a true mid driver, not as a midbass. The result is better midrange. For moderate level music this is probably the best option. With subs you typically pay for a design that can accomodate 1" or more excursion that is needed for the lowest octave. You don't need this for music, unless you like it very loud, in which case your amp will often run out of steam before the driver runs out of excursion.
I suggest two choices:
One, get a sub that's optimised for fidelity over output. Look for a low distortion motor - XBL or a motor with faraday rings etc. Drivers like Adire Koda or Lamda (now supported by AE speakers). Another promising option is Rythmic audio's direct servo kit.
Alternatively consider using bi-amped woofers rather than subs. The big advantage with this that is good for music is you can cross higher than with a sub - say 200 or 300 Hz. The mid driver then can act as a true mid driver, not as a midbass. The result is better midrange. For moderate level music this is probably the best option. With subs you typically pay for a design that can accomodate 1" or more excursion that is needed for the lowest octave. You don't need this for music, unless you like it very loud, in which case your amp will often run out of steam before the driver runs out of excursion.
Well I went from peerless 850146 to 10"XLS. This lot is in a 3 way setup so the bass driver covers much more then a sub would.
The main reason I wanted the XLS was because it requires a tiny box. Mine are sealed with EQ and driven by a 200 watt amp.
Now I wasnt too bothered if the XLS didnt sound any better then the 850146 because what I wanted was the smaller box. But the XLS was noticeably cleaner with less distortion.
So no I dont think a huge driver like these are overkill for music listening.
The main reason I wanted the XLS was because it requires a tiny box. Mine are sealed with EQ and driven by a 200 watt amp.
Now I wasnt too bothered if the XLS didnt sound any better then the 850146 because what I wanted was the smaller box. But the XLS was noticeably cleaner with less distortion.
So no I dont think a huge driver like these are overkill for music listening.
I still don't have too many pieces of info about the amp but what I know is that it's 2x200 or 2x250 W and it is bridgeable. (I'm sure it can drive an 8 Ohm speaker bridged). I will try it anyway. I'll tell you about the results next week.
Hi guys,
I have finished my amp and sub (at least so far🙂.
It has high level inputs from my (Gainclone) stereo channels, an input buffer, a Linkwitz-transform, a low pass filter, and the signal is fed into a 250W mosfet amp. The amp is used by my band as a vocal monitor amp, so it's not hifi, and not dead-quiet, but I just wanted to try it so it will be replaced later. The box is closed, with the Peerless xls10 driver, the resonance frequency I measured was perfectly as calculated, 43 Hz. I have ordered a Behringer Feedback Destroyer which I will use as a digital eq for taming my worst room mode at 61 Hz (and maybe some others also). This 61 Hz boom is most probably coming from the longest distance in the room which is 5m 55cm. I already tried to dampen one of the walls at the end of this longest distance which helped a lot. Now if I go to the corner and listen to the bass then I can hear that the boomy sound is not there (as it was before, but just in the corner). I think this step will make the eqing also easier in the future.
Placing the sub was done with the method when you put the sub in the listening position and search for a good bass around the room. I also used the room060d.xls, and found that the place picked by ear is also reported to be a good place by the xls file.
Now the only problem I have is that the bass is best at a position other than the listening position. It's a pain to see that the spot where the main speakers sound the best is not the one where the cleanes, deepest bass can be heard. Other than this, the bass sound is far better than anything I heard before. It's not delayed, the kick drum sound comes right when it comes from the main speakers. The sub doesn't mess up the bass guitar (mid low) sounds, only adds the lower register which was missing. Stereo imaging was not hurt at all (I haven't noticed so far at least).
What I don't know is how to get the best bass sound at the same place where the best stereo (main spkrs) sound can be heard. And another thing, I'd like to get a Radio Shack digital spl-meter but Radio Shack is not taking international orders from Europe and nobody sells their products over here. I have run a search at e-bay also, found nothing but test-tone cds. Any ideas?
I have finished my amp and sub (at least so far🙂.
It has high level inputs from my (Gainclone) stereo channels, an input buffer, a Linkwitz-transform, a low pass filter, and the signal is fed into a 250W mosfet amp. The amp is used by my band as a vocal monitor amp, so it's not hifi, and not dead-quiet, but I just wanted to try it so it will be replaced later. The box is closed, with the Peerless xls10 driver, the resonance frequency I measured was perfectly as calculated, 43 Hz. I have ordered a Behringer Feedback Destroyer which I will use as a digital eq for taming my worst room mode at 61 Hz (and maybe some others also). This 61 Hz boom is most probably coming from the longest distance in the room which is 5m 55cm. I already tried to dampen one of the walls at the end of this longest distance which helped a lot. Now if I go to the corner and listen to the bass then I can hear that the boomy sound is not there (as it was before, but just in the corner). I think this step will make the eqing also easier in the future.
Placing the sub was done with the method when you put the sub in the listening position and search for a good bass around the room. I also used the room060d.xls, and found that the place picked by ear is also reported to be a good place by the xls file.
Now the only problem I have is that the bass is best at a position other than the listening position. It's a pain to see that the spot where the main speakers sound the best is not the one where the cleanes, deepest bass can be heard. Other than this, the bass sound is far better than anything I heard before. It's not delayed, the kick drum sound comes right when it comes from the main speakers. The sub doesn't mess up the bass guitar (mid low) sounds, only adds the lower register which was missing. Stereo imaging was not hurt at all (I haven't noticed so far at least).
What I don't know is how to get the best bass sound at the same place where the best stereo (main spkrs) sound can be heard. And another thing, I'd like to get a Radio Shack digital spl-meter but Radio Shack is not taking international orders from Europe and nobody sells their products over here. I have run a search at e-bay also, found nothing but test-tone cds. Any ideas?
Ultracurve DEQ with a mic does the same thing as an SPL meter (with or without A and C weighting and with much more accuracy overall). I can get the RS meters here in Australia, I wonder if they are in fact available in Europe. Perhaps under a different name.
Congrats on things so far 😉
Pics?
You don't need the subs to be right next to the mains, you can try moving them around a bit. I've experimented with using digital delay when placing the subs close, but it's really difficult to determine if it actually makes a perceivable difference. If I give the subs 100m delay it's weird and obvious, but with just 2m I can't really tell. Ideally you would have the subs located so you can't localise them as well.
Congrats on things so far 😉
Pics?
You don't need the subs to be right next to the mains, you can try moving them around a bit. I've experimented with using digital delay when placing the subs close, but it's really difficult to determine if it actually makes a perceivable difference. If I give the subs 100m delay it's weird and obvious, but with just 2m I can't really tell. Ideally you would have the subs located so you can't localise them as well.
Localising the sub's sound is not a problem, because now it cannot be localised 🙂
At least not by ear. By eye it's okay. 🙂
Even those sounds having particles in both the main channels and the sub (like kick drums) sound as they were sent only from the mains. The bassdrum sounds right from the middle of the stage. And of course those crazy low frequency pards added... Hmmm... 🙂
The location of the sub now is on the far left, 1.5 m from the left main speaker, next to the front left corner (from the listening position). It's not really in the corner, its distance from the front wall is 90 cm. (Now I call a 'front wall' the wall behind the main speakers, so the wall you look at when listening).
The delay things I'm not sure about. I've seen on my oscilloscope that my sub preamp output is not in phase with the main speakers (unfortunately). It's delayed a bit, but I haven't checked it at different frequencies (I will do it later) so I can't really tell about it but I guess this will change with freq. This way, it's hard to tell what the distance should be between the sub and the listening position. Maybe it should be closer to me than the main speakers. I have seen setups where the sub is right next to the sofa set at the listening position. Maybe I'll try that also (though I couldn't decide which direction the sub should face since it's not downfiring).
I will try to attach some pics tomorrow (I have to make them first).
At least not by ear. By eye it's okay. 🙂
Even those sounds having particles in both the main channels and the sub (like kick drums) sound as they were sent only from the mains. The bassdrum sounds right from the middle of the stage. And of course those crazy low frequency pards added... Hmmm... 🙂
The location of the sub now is on the far left, 1.5 m from the left main speaker, next to the front left corner (from the listening position). It's not really in the corner, its distance from the front wall is 90 cm. (Now I call a 'front wall' the wall behind the main speakers, so the wall you look at when listening).
The delay things I'm not sure about. I've seen on my oscilloscope that my sub preamp output is not in phase with the main speakers (unfortunately). It's delayed a bit, but I haven't checked it at different frequencies (I will do it later) so I can't really tell about it but I guess this will change with freq. This way, it's hard to tell what the distance should be between the sub and the listening position. Maybe it should be closer to me than the main speakers. I have seen setups where the sub is right next to the sofa set at the listening position. Maybe I'll try that also (though I couldn't decide which direction the sub should face since it's not downfiring).
I will try to attach some pics tomorrow (I have to make them first).
I've tried subs either side of the couch. I liked it at first as the response was much smoother that way. However, it also made the whole couch into a large tactile transducer, sounded as if the bass was coming from inside my head at times. So far I'm happier with the subs with the mains at the moment. I'd like to try it again but I don't think I can get it to work in a way I'm totally satisfied. I get more output with them close 🙁
what do you mean by "subs with the mains"? How close they are to each other? Are the subs between the fronts?
I haven't tried this sub position by the couch yet, but I will give it a try. It will look odd since I do not have stereo subs. I have only one.
The other thing that keeps me wondering is how I could make to sound my sub the best at the listening position, not anywhere else. Now my sub fires accross the room, from the left to the right, and its line is only 1,5 m in front of the listening position. If I move forward (closer to the front speakers) then the bass is deeper, cleaner and its volume can be decreased for the same feeling. (Of course stereo image is worse there). Now I'm thinking about moving my sub somewhere so as its "sweet spot" is at least near to that of the front speakers. I also heard that its not a good solution to use the sub firing crosswise in front of the main speakers but I don't know why. I don't have a problem with it.
I haven't tried this sub position by the couch yet, but I will give it a try. It will look odd since I do not have stereo subs. I have only one.
The other thing that keeps me wondering is how I could make to sound my sub the best at the listening position, not anywhere else. Now my sub fires accross the room, from the left to the right, and its line is only 1,5 m in front of the listening position. If I move forward (closer to the front speakers) then the bass is deeper, cleaner and its volume can be decreased for the same feeling. (Of course stereo image is worse there). Now I'm thinking about moving my sub somewhere so as its "sweet spot" is at least near to that of the front speakers. I also heard that its not a good solution to use the sub firing crosswise in front of the main speakers but I don't know why. I don't have a problem with it.
My mains are set in from the front walls by a metre, 0.7m on the left and more on the right. The subs are against the side walls, in line with them along the length of the room. The path difference is negligable.
Couchside sub could look just like a coffee table. I had mine like that and I used it as a table for a while, although my drink did move at times!
Subs are pretty much omnidirectional - which way it faces is for the most part irrelevant. Out of band harmonic distortion products from the front of the cone would have a higher frequency content. They are often the cause of localisation, and the reason subs don't always quite perform the disappearing act they ideally should. This is one reason to try to keep them fairly close to the mains. Avalanche claim their subs don't have this problem due to low distortion, and my experience seems to agree with this. I have heard an M&K sub placed in a position you would expect to hear it (rear), but you even if you are right up close to it. It was the top of the range model, with two drivers push pull mounted.
Perhaps at a later date, when I want to get into sub upgrades, I might add on some lower distortion subs and place them direct field and see if I can pull it off. Much less eq is needed when they are in this position. They can actually be as flat as your mains as they send more of their energy directly to you, much less to the room. If you are within 0.5m and the walls are 2 and 3m away then the output is down 12 & 15 db respectively before it even hits the wall - hence there is MUCH less energy in the modes. Normally you don't get that "direct field" bass overshadowing the room modes, so what you hear is in fact dominated by modes.
Couchside sub could look just like a coffee table. I had mine like that and I used it as a table for a while, although my drink did move at times!
Subs are pretty much omnidirectional - which way it faces is for the most part irrelevant. Out of band harmonic distortion products from the front of the cone would have a higher frequency content. They are often the cause of localisation, and the reason subs don't always quite perform the disappearing act they ideally should. This is one reason to try to keep them fairly close to the mains. Avalanche claim their subs don't have this problem due to low distortion, and my experience seems to agree with this. I have heard an M&K sub placed in a position you would expect to hear it (rear), but you even if you are right up close to it. It was the top of the range model, with two drivers push pull mounted.
Perhaps at a later date, when I want to get into sub upgrades, I might add on some lower distortion subs and place them direct field and see if I can pull it off. Much less eq is needed when they are in this position. They can actually be as flat as your mains as they send more of their energy directly to you, much less to the room. If you are within 0.5m and the walls are 2 and 3m away then the output is down 12 & 15 db respectively before it even hits the wall - hence there is MUCH less energy in the modes. Normally you don't get that "direct field" bass overshadowing the room modes, so what you hear is in fact dominated by modes.
Hmm. Sounds nice.
I don't know how much distortion comes out of my sub (it shouldn't be too much because my xls 10 should be far within the excursion limits) but If it is placed well it cannot be pointed by ear. On the other hand yesterday I tried to move it around the room, I even tried the position next to the couch, I did't like it. It was somehow pushing the picture to the other side. I could hear that most of the bass energy was coming from one side only so I moved the sub back where it was, close to the front left corner. What I changed is that the sub is now firing at me and not accross the room. It's better for mid bass, and maybe this setup has less influence on the mains' sound and stereo imaging.
The next big step I'll take is installing the Behringer FD. It should get here within a week or two. The only question is how I will manage to find an SPL-meter until then.
Some pics I took yesterday.
This is how my gainclone looked at before adding the sub to the system.
I don't know how much distortion comes out of my sub (it shouldn't be too much because my xls 10 should be far within the excursion limits) but If it is placed well it cannot be pointed by ear. On the other hand yesterday I tried to move it around the room, I even tried the position next to the couch, I did't like it. It was somehow pushing the picture to the other side. I could hear that most of the bass energy was coming from one side only so I moved the sub back where it was, close to the front left corner. What I changed is that the sub is now firing at me and not accross the room. It's better for mid bass, and maybe this setup has less influence on the mains' sound and stereo imaging.
The next big step I'll take is installing the Behringer FD. It should get here within a week or two. The only question is how I will manage to find an SPL-meter until then.
Some pics I took yesterday.
This is how my gainclone looked at before adding the sub to the system.
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