ShinOBIWAN said:Hi Badman, interesting suggestion. I have questions
I've never built a cabinet with opposing woofers. I've heard about the mechanical vibration energy from opposing drivers being 180 degrees out of phase thus cancelling and decreasing cabinet borne noise but how real, and audible, is this problem?
Isn't the existing cabinet construction sturdy enough to negate such things? For example: 81mm thick baffles, 34mm side/top/rear walls and 25mm bracing.
Another thing to consider is that the rear of the cabinet will be close to a wall. Wouldn't this be a recipe for bass nasties in such a situation?
How close? If you've got a little breathing room, you should be fine, talking 15-18" here. I realize that they're quite deep already, so that does indeed push them out into the room a bit. The slenderness of the baffle isn't going to do much besides keep it stiff (and I think 81mm is a lot more than you need, half that will be plenty dead)
As to the value of force cancellation: in your builds, there's probably not a lot of cabinet performance left on the table, but say you were able to cut the baffle thickness in half without sacrificing, or even with TINY gains, in performance: I know you're the kind of guy to do it 'right'
The other option would be to go sidefiring. You could have them sidefiring, directly against the wall, and behind the mains, in the configuration I laid out. Another advantage is that by having the surfaces spread around, you tend to average out some of the room involvement.
I'm sure you'll come up with some wild bass quality no matter what you do. I'll take your prototypes, I'll even give you $50 for shipping)
When the bass tones bounce off the rear wall in close timing to the front wave, they tend to create more and more powerful room nodes aka nasties.
In my living room, my sub is up against a wall for spousal acceptance. As a result, up close it is not all to loud or boomy, but out in the room there are places where it sounds like a teenager in a honda with more money in his stereo than his car is driving by making himself deaf. In my main system downstairs, the subs are about 8 feet from the rear wall and 3 feet from the side walls. It made a big difference when I was able to pull them out in the room.
In my living room, my sub is up against a wall for spousal acceptance. As a result, up close it is not all to loud or boomy, but out in the room there are places where it sounds like a teenager in a honda with more money in his stereo than his car is driving by making himself deaf. In my main system downstairs, the subs are about 8 feet from the rear wall and 3 feet from the side walls. It made a big difference when I was able to pull them out in the room.
ShinOBIWAN said:
D*mn you Ant... I've been planning a dual sub system with a total of 'only' 4 XLS10s
badman said:
Without, admittedly, any real data to back up my results, I'd agree with badman.
As part of the above 2 x 2 XLS10 idea, I built a 40 litre sealed enclosure with opposing drivers. The box was a real POS - no bracing, no padding; just glue something together with a couple of baffles as a quick test.
To my surprise, it sounds very nice, and even with major excursion, you can put your hand on the box and it does feel as though it's not vibrating. As I said, not very scientific, and no measurements, but it was promising.
ShinOBIWAN said:
So then Scott. If you had 190ltrs to play with what would you do.<walks off casually whistling>
Bear in mind that bass arrays are an aesthetic match with the mains and bigass boxes like these need some kind of running theme because they just don't blend. I choose to make them a focal point alongside the mains instead. People will walk in, see them, and say "my you have small ones"
I've given this some thought now.. but you already have drivers and I'm sure what you will come up with on your own will be excellent!
..of course if you want to do something comparable to your RAAL's but in the bass and sub-bass, well.. let me know.
Thanks for all the suggestions so far BTW. Especially the opposing arrays. However I don't think I'll be able to really pull off that off. You see I want to keep this form factor so that means 4 passive radiators on the rear. These cost £45 each but the thing is you can get the XLS10(with motor) for £59 each - daft huh. For that £14 extra I'd go with the active drivers on principle. There's not just that conundrum either because with just a few inches worth of clearance between the wall and the rear of cabinet, there's going to be real problems. The side firing suggestion would work but that'd mean a big blank front baffle and I want the drivers firing at the listening position.
Having said all that I'm certainly interested enough in the idea opposing drivers to keep it in mind for a future project though.
OK so after the suggestions on aesthetics I went back and tried to tweak the angled cuts that I'd previously dismissed. This looks better than before, still not 100% sure though.
Having said all that I'm certainly interested enough in the idea opposing drivers to keep it in mind for a future project though.
OK so after the suggestions on aesthetics I went back and tried to tweak the angled cuts that I'd previously dismissed. This looks better than before, still not 100% sure though.
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I understand that you're not quite sure, but I am definately sure that the angled baffle very much fit's in better.
I too made up a very similar box for the four Peerless 10's, taking the cue directly from you in the winter project thread of yours elsewhere (thanks for your help on that).
Mine (tho never finished and only ever in raw MDF) looked very much like your square mockup.
To be honest, I was not that happy with the results, was too long ago for me to articulate why as I don't truly recall, but vaguely I remember not being that impressed with the bass output I was expecting. I was after the 'wall of woofers' look which that layout gives.
I ended up taking a saw to one of the boxes, halving it's height, cut new opposing holes on the rear and laying the result horizontally on the floor.
Ahh, now I had extension flat to thirteen hz in the room, a vast difference.
The funny thing? I never watch movies (and these are in my dedicated music room so no TV anyway) so I ended up removing the subs all together.....I very quickly got to actively hate the low bass in music! My current setup uses 18 PHL pro drivers, and to be honest I only get flat in the room to 29 hz, after which it drops like a stone.
So when it had extension to thirteen hz, WOW the first time you play a track and you're surfing at the listening position it's fantastic. The second time it's good, the third time it's interesting, the fourth time it's positively irritating.
I mean there were times when I'd be shaking in the listening position and there NO CUES at all in the music to indicate why it should be so!
Anyway, my ears and my preferences, others could very well be different, out came the subs and I stick with my mains. I only lose the bottom ten hz in music, not much loss really in my own book, maybe different for others.
I too made up a very similar box for the four Peerless 10's, taking the cue directly from you in the winter project thread of yours elsewhere (thanks for your help on that).
Mine (tho never finished and only ever in raw MDF) looked very much like your square mockup.
To be honest, I was not that happy with the results, was too long ago for me to articulate why as I don't truly recall, but vaguely I remember not being that impressed with the bass output I was expecting. I was after the 'wall of woofers' look which that layout gives.
I ended up taking a saw to one of the boxes, halving it's height, cut new opposing holes on the rear and laying the result horizontally on the floor.
Ahh, now I had extension flat to thirteen hz in the room, a vast difference.
The funny thing? I never watch movies (and these are in my dedicated music room so no TV anyway) so I ended up removing the subs all together.....I very quickly got to actively hate the low bass in music! My current setup uses 18 PHL pro drivers, and to be honest I only get flat in the room to 29 hz, after which it drops like a stone.
So when it had extension to thirteen hz, WOW the first time you play a track and you're surfing at the listening position it's fantastic. The second time it's good, the third time it's interesting, the fourth time it's positively irritating.
I mean there were times when I'd be shaking in the listening position and there NO CUES at all in the music to indicate why it should be so!
Anyway, my ears and my preferences, others could very well be different, out came the subs and I stick with my mains. I only lose the bottom ten hz in music, not much loss really in my own book, maybe different for others.
Terry first I must apologise, this is twice in as many weeks that I'm going to suggest your doing it wrong but natural bass is great bass, if you didn't like the subs running with the mains then, I'm sorry to say, you got something wrong.
You shouldn't be shaking the room unless your listen at very loud SPL's. When integrated and EQ'd correctly the <30hz range adds space as well as weight to music, it should never make things closed in or annoying. You shouldn't even be consciously singling out that the extra bass is there. Number one mistake is to have the subs playing over the mains and not with them. This, as you point out, sounds impressive at first but is pretty cr@p with repetition.
I've heard very few setups with subs working as they should for music and most folks just don't bother because they can't get it right - much better to do without than to have a system ruined by bass.
Its a tough nut to crack initially. HT is much more forgiving and here you want impressive bass that makes itself known. This attribute perfectly fits the spectacle of a movie and its here where bass should provoke strong emotional reactions. Music however has its primary emotional pull firmly rooted in the ranges above 50hz. Movies rely on hit and run tactics for bass, the big moments are quite rare considering the length of an average film but this is exactly what keeps them impressive. Music is repetitive and that constant drone of overblown deep bass will quickly have anyone reaching for the plug.
I know you haven't said this directly but there's a fair amount of talk saying that subs aren't to be used with a stereo playback system but, to me, that's like saying midrange drivers aren't to be used with them either. It just takes effort and a good acoustic and/or DSP horsepower because the room is a huge problem here - much more so than it is to midrange performance. For the relative wavelengths involved its like sticking a small bookshelf speaker in a large cupboard and expecting it to sound good. That's not going to happen without some effort.
In my own setup(well, previous ones) and with it all being DSP based, I have two distinct bass profiles for music and movies. I've tried using one setup for all situations and it doesn't work, you either take away from movies or you make your stereo playback less so than it was without the subs.
You shouldn't be shaking the room unless your listen at very loud SPL's. When integrated and EQ'd correctly the <30hz range adds space as well as weight to music, it should never make things closed in or annoying. You shouldn't even be consciously singling out that the extra bass is there. Number one mistake is to have the subs playing over the mains and not with them. This, as you point out, sounds impressive at first but is pretty cr@p with repetition.
I've heard very few setups with subs working as they should for music and most folks just don't bother because they can't get it right - much better to do without than to have a system ruined by bass.
Its a tough nut to crack initially. HT is much more forgiving and here you want impressive bass that makes itself known. This attribute perfectly fits the spectacle of a movie and its here where bass should provoke strong emotional reactions. Music however has its primary emotional pull firmly rooted in the ranges above 50hz. Movies rely on hit and run tactics for bass, the big moments are quite rare considering the length of an average film but this is exactly what keeps them impressive. Music is repetitive and that constant drone of overblown deep bass will quickly have anyone reaching for the plug.
I know you haven't said this directly but there's a fair amount of talk saying that subs aren't to be used with a stereo playback system but, to me, that's like saying midrange drivers aren't to be used with them either. It just takes effort and a good acoustic and/or DSP horsepower because the room is a huge problem here - much more so than it is to midrange performance. For the relative wavelengths involved its like sticking a small bookshelf speaker in a large cupboard and expecting it to sound good. That's not going to happen without some effort.
In my own setup(well, previous ones) and with it all being DSP based, I have two distinct bass profiles for music and movies. I've tried using one setup for all situations and it doesn't work, you either take away from movies or you make your stereo playback less so than it was without the subs.
Yeah Hi Shin
gee I don't recall the first 'admonition' of which you speak!, but in all likelihood you do them in such a diplomatic manner that no-one gets their feathers ruffled heh heh, maybe a bit like the sharpest knife goes in easiest!!
Heck, I agree with you 100% regarding how a sub should be integrated, as you say it needs to be seamless and totally in balance. I too feel that anyone that says subs should not be used with a serious Hi Fi system simply has not heard a properly set up stereo system with subs, as you rightly point out.
High SPLs?? Ha ha, how well you know me.
I use a deqx, and so to integrate these subs and still be able to maintain preamp control over the volume I needed to have a splitter out of the bass output, and ran the second into a DCX I had laying around. Then by measurement and use of the PEQs in the behringer I was able to juggle back and forth to get the subs to integrate flat with the mains. To get the mains alone flat to 29 hz, requires an awful lot of EQ, as in the box they actually start to roll off at 70 hz or so. My theory was that by removing that amount of EQ from the mains would take a lot of the 'stress' of them, even tho that dtress is never evident in actual listening, just a theoretical thing.
So the whole setup measured flat to thirteen hz in the end. So the subs were not 'hot' in any way.
As the DCX has no real control under twenty hz, and the highpass of the DCX at twenty hz (even if 48 db) started to actually come into effect at something like 25 hz or so, but seeing as how I could get flat to 29 hz anyway there seemed little point in having all the drivers, amps and DCX unit to change the response from 29 down to 25 hz, so I didn't bother to use the highpass function, giving me essentially a flat response to thirteen.
That was when the uncorrelated subterranean rumbles in the music happened, and as I say even in one case an unheard but seat shaking with NO musical input that could be heard. Maybe a glitch on the recording or whatever, but annoying nonetheless.
Still, as I say that is only my experience and tastes, and I have absolutely NO doubt that your knowledge and experience vastly exceeds mine and so would be willing to bet that you would get a vastly superior result to mine.
I would also imagine that the bass drivers in yours would heave a bigger sigh of relief than my 18s did, which once again comes back to each situation is different and so results most certainly will vary.
I was not trying to talk anyone out of it, far from it. Just a thought (cept I've already cut one box up) maybe the bottom extension 'problem' I spoke of would actually be ameliorated if I stuck to the original vertical four alignment? Hmm, maybe I was too quick on the draw with the saw.
gee I don't recall the first 'admonition' of which you speak!, but in all likelihood you do them in such a diplomatic manner that no-one gets their feathers ruffled heh heh, maybe a bit like the sharpest knife goes in easiest!!
Heck, I agree with you 100% regarding how a sub should be integrated, as you say it needs to be seamless and totally in balance. I too feel that anyone that says subs should not be used with a serious Hi Fi system simply has not heard a properly set up stereo system with subs, as you rightly point out.
High SPLs?? Ha ha, how well you know me.
I use a deqx, and so to integrate these subs and still be able to maintain preamp control over the volume I needed to have a splitter out of the bass output, and ran the second into a DCX I had laying around. Then by measurement and use of the PEQs in the behringer I was able to juggle back and forth to get the subs to integrate flat with the mains. To get the mains alone flat to 29 hz, requires an awful lot of EQ, as in the box they actually start to roll off at 70 hz or so. My theory was that by removing that amount of EQ from the mains would take a lot of the 'stress' of them, even tho that dtress is never evident in actual listening, just a theoretical thing.
So the whole setup measured flat to thirteen hz in the end. So the subs were not 'hot' in any way.
As the DCX has no real control under twenty hz, and the highpass of the DCX at twenty hz (even if 48 db) started to actually come into effect at something like 25 hz or so, but seeing as how I could get flat to 29 hz anyway there seemed little point in having all the drivers, amps and DCX unit to change the response from 29 down to 25 hz, so I didn't bother to use the highpass function, giving me essentially a flat response to thirteen.
That was when the uncorrelated subterranean rumbles in the music happened, and as I say even in one case an unheard but seat shaking with NO musical input that could be heard. Maybe a glitch on the recording or whatever, but annoying nonetheless.
Still, as I say that is only my experience and tastes, and I have absolutely NO doubt that your knowledge and experience vastly exceeds mine and so would be willing to bet that you would get a vastly superior result to mine.
I would also imagine that the bass drivers in yours would heave a bigger sigh of relief than my 18s did, which once again comes back to each situation is different and so results most certainly will vary.
I was not trying to talk anyone out of it, far from it. Just a thought (cept I've already cut one box up) maybe the bottom extension 'problem' I spoke of would actually be ameliorated if I stuck to the original vertical four alignment? Hmm, maybe I was too quick on the draw with the saw.
I like the simple front shaped bass tower better than the angled one aesthetically, and near to the LGT. It plays bass and it must be looking more determined. Plus having the same angled face edges and not the concave shape, looks like trying to be an LGT part, but it did not make it, somehow.
And...take it easy with the DSP in the modal region. Up to a couple or three peaks you treat, and don't fill gaps. It will screw too much of the total impulse response if you overuse it, and although under 200Hz FR can be made to look pristine, it will sound constipated as a whole. Proceed with caution...
And...take it easy with the DSP in the modal region. Up to a couple or three peaks you treat, and don't fill gaps. It will screw too much of the total impulse response if you overuse it, and although under 200Hz FR can be made to look pristine, it will sound constipated as a whole. Proceed with caution...
terry j said:
It sounds like you gave them a fair shot. More could have been had no doubt but, by the sounds of it, there was hardly a pressing need for extra bass to start with. I think you were right getting rid of the subs and concentrating on the mains, making sure they were playing at their best. Not everything in audio works in all situations so why handicap a good system with something that clearly wasn't working to taste.
Its amazing the image folks build up of other folks on forums. You couldn't be further from the truth! I'm intrepid when I tackle a project and certainly addicted but don't mistake those things as a sign of any more knowledge than the next guy. We all have our own little way of interpreting and solving problems, mine are wrought through with sheer persistence, a tiny amount of luck and a good chunk of failure. Eventually through the sheer volume of errors and repetition I learn something. And that's the difference because for bright folks, banging their head against a wall just the once is enough to realise not to do it again.
I'm a head banger
No doubt about that, the poor little 8" drivers really don't take kindly to liberal use of the volume during movies. Playing at reference levels with the LFE routed to the mains, I've heard them distort on demanding tracks.
Yes the vertical array would avoid some floor loading. This might have been beneficial because you mentioned that you weren't impressed with the vertical array of subs so cut them up and placed all the drivers close to the floor. You noted this was impressive but quickly became tiring. Just a guess of course but the other configuration might have been more fulfilling in the long run after some determined tweaking.
ScottG said:The middle one.
And yes, we likes da' bass - da' deep, deep, deep, deep, deep, deep, deep, deep, deep, deep, deep, deep, deep - BASS. (..oh wait a minute, seems I left a "deep" or two out.)
a.k.a. infrasonic for those geeks out there.
Deep bass, yep got that but don't forgot there's also deep dish alloy wheels, deep hole and kinda related to that, there's deep thro...
ShinOBIWAN said:
That was my impression of the twin XLS10 prototype I built - I was pleasantly surprised that it gave me a bit more 'slam' for movies, but was very subtle for music. It just adds a little more depth on bass heavy music (stuff like Tool) but never announced 'SUB OVER HERE!'
You can definitely hear the difference with/without the sub, but it's never tiring.
The only real effort I put into the prototype was making sure I balanced the levels across all speakers with an SPL meter.
BTW Ant - I'll add a vote for the sub tower with angled corners. Looks much more complementary to the LGTs.
I rather like the flat fronts too. What about triangular though? You can do a large triangular enclosure with the hypotenuse along the wall and the right angle right behind the mains, and drivers firing out to the sides.
The advantage of NOT facing the drivers right at yourself is that higher frequency products (either post-filter remnants or distortion components) are more difficult to localize, so it reduces the little bit of 'voices from subs' that people so often get in poorly set up systems.
I like your modesty ant- headbanging. I'm a little different than you, in that I don't generally take projects to the extreme unless I've knocked up some similar units as fugly protos.
Of course, sometimes the most brilliant ideas get built 'all out' (and I assure you, your 'all out' is much prettier than mine).
Something to be said for your method- certainly you're leaving very little on the table for giving your drivers great environments. I've heard great drivers sound awful, so at least you're not doing that!
The advantage of NOT facing the drivers right at yourself is that higher frequency products (either post-filter remnants or distortion components) are more difficult to localize, so it reduces the little bit of 'voices from subs' that people so often get in poorly set up systems.
I like your modesty ant- headbanging. I'm a little different than you, in that I don't generally take projects to the extreme unless I've knocked up some similar units as fugly protos.
Of course, sometimes the most brilliant ideas get built 'all out' (and I assure you, your 'all out' is much prettier than mine).
Something to be said for your method- certainly you're leaving very little on the table for giving your drivers great environments. I've heard great drivers sound awful, so at least you're not doing that!
I like the non-flat subs.
Shin, you should be able to get away with opposing active woofers if the gap area around the speaker back to the wall is equal or greater than the total SD of the rear drivers.
A system with front drivers, and one with front and rear driers will both act as an omni directional source so why not use more drivers?
You could experiment with di-pole too then if you wanted. They can work quite close to walls in the bass.
Shin, you should be able to get away with opposing active woofers if the gap area around the speaker back to the wall is equal or greater than the total SD of the rear drivers.
A system with front drivers, and one with front and rear driers will both act as an omni directional source so why not use more drivers?
You could experiment with di-pole too then if you wanted. They can work quite close to walls in the bass.
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