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Post by jdubs on Dec 15, 2015 8:59:41 GMT -5
I'll read through that in more detail when I get a chance. I'm kinda open to whatever is going to work best. (Although I am doing 2 identical subs, but I could keep my REL for subsonic. I don't think that will be needed; see below) I should state that when I started this I assumed I was going to do dual mono. I figured this was the best way to eliminate dead spots (so both subs were outputting the same signal). Now I am learning more and will have to try different set-ups. And honestly, for serious listening there is ONE spot I sit but I do sit over at the computer and listen at the same time, too. My system is in my signature, but here is what I'm thinking. Before I got my XSP-1 (which I got with this project in mind), I used my XDA-2 as my pre-amp. I had the REL subwoofer connected high level to my amps. The speakers ran full range, which they are very capable of. I had the REL crossed over below the mains. This worked very well, but could get muddy at times and the bass just wasn't as tight as I wanted it. I got the XSP-1, set the cross-over as low as its goes (50) and ran the REL lo-level mono out. Immediately I noticed a difference. I feel that once I go two sealed subs, regardless of stereo or dual mono, there will be a huge improvement. I will continue to crossover very low, although I will play with it to find the optimum. I feel that getting mid-bass out of my mains will remain key to imaging and punchy bass. So, my subs will only play 50-60 Hz and down. I plan to EQ them to reduce peaks and be sure they extend as low as possible. I want to say their F3 in a sealed box is somewhere 30-32 Hz. I am seriously considering adding Dirac with something like this: www.minidsp.com/products/dirac-series/ddrc-22d
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Post by yves on Dec 15, 2015 9:31:40 GMT -5
I'll read through that in more detail when I get a chance. I'm kinda open to whatever is going to work best. (Although I am doing 2 identical subs, but I could keep my REL for subsonic. I don't think that will be needed; see below) I should state that when I started this I assumed I was going to do dual mono. I figured this was the best way to eliminate dead spots (so both subs were outputting the same signal). Now I am learning more and will have to try different set-ups. And honestly, for serious listening there is ONE spot I sit but I do sit over at the computer and listen at the same time, too. My system is in my signature, but here is what I'm thinking. Before I got my XSP-1 (which I got with this project in mind), I used my XDA-2 as my pre-amp. I had the REL subwoofer connected high level to my amps. The speakers ran full range, which they are very capable of. I had the REL crossed over below the mains. This worked very well, but could get muddy at times and the bass just wasn't as tight as I wanted it. I got the XSP-1, set the cross-over as low as its goes (50) and ran the REL lo-level mono out. Immediately I noticed a difference. I feel that once I go two sealed subs, regardless of stereo or dual mono, there will be a huge improvement. I will continue to crossover very low, although I will play with it to find the optimum. I feel that getting mid-bass out of my mains will remain key to imaging and punchy bass. So, my subs will only play 50-60 Hz and down. I plan to EQ them to reduce peaks and be sure they extend as low as possible. I want to say their F3 in a sealed box is somewhere 30-32 Hz. I am seriously considering adding Dirac with something like this: www.minidsp.com/products/dirac-series/ddrc-22dFor stereo music listening, I think the article that you linked in your first post is spot on. For multichannel sound, however, ignoring the Todd Welti paper would be simply naive because that would be like asking the science of acoustics to apologize for the fact that it's hard and unrefuted science.
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djreef
Sensei
Thoroughly enjoying my Schiit
Posts: 353
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Post by djreef on Dec 15, 2015 21:37:51 GMT -5
The concept of "stereo sound" is to maintain and enhance directionality, sound staging. Since frequencies below around 80 Hz are non directional (ie; their wavelength is over 3.5 metres long) the concept of sound staging doesn't apply to sub woofers like it does to woofers, mid range, tweeters etc. in some systems what is loosely called a sub woofer is actually handling the frequencies of a woofer ie; producing frequencies above 80 Hz. In this case they can benefit from stereo sound staging. There are benefits in having 2 subs but if the case of a true sub woofer then stereo sound staging isn't one of them. Cheers Gary That might be true, to a point - unless the individual who mixes the recording specifically places the LF in one channel (ie mixing the bass guitar or double bass to the far side of the sound stage) like many classic jazz recordings are mixed. Just check my avatar to see where my preference lies. DJ
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Post by yves on Dec 16, 2015 11:16:16 GMT -5
The concept of "stereo sound" is to maintain and enhance directionality, sound staging. Since frequencies below around 80 Hz are non directional (ie; their wavelength is over 3.5 metres long) the concept of sound staging doesn't apply to sub woofers like it does to woofers, mid range, tweeters etc. in some systems what is loosely called a sub woofer is actually handling the frequencies of a woofer ie; producing frequencies above 80 Hz. In this case they can benefit from stereo sound staging. There are benefits in having 2 subs but if the case of a true sub woofer then stereo sound staging isn't one of them. Cheers Gary That might be true, to a point - unless the individual who mixes the recording specifically places the LF in one channel (ie mixing the bass guitar or double bass to the far side of the sound stage) like many classic jazz recordings are mixed. Just check my avatar to see where my preference lies. DJ Regardless of how it was mixed, even if the bass below 80 Hz has been recorded to mono, it can still affect the directionality/sound staging. This is because muddy bass has a strong tendency to muddy up the entire sound, and muddy up the spatial cues that are way above 80 Hz. If the bass below 80 Hz has been recorded to stereo, then if it is played back in mono (i.e., played back through a single subwoofer channel, as opposed to a pair of stereo subs), phase cancellations will result from the summing that occurs, thereby causing the bass to be distorted. It is this bass *distortion* that messes up the realistic feel and stereo imaging. Further, on a good pair of big floorstanding loudspeakers the frequency response of which reaches way down to 35 Hz without it producing noticeable distortions, for example, often times you will find that setting the crossover point for your added subwoofer(s) as low as 50 Hz or even lower yields better quality sound in terms of stereo realism than setting it at 60 Hz or higher. An important part of the reason why this can happen is because the crossover region can do more damage to the stereo sound of the floorstanders than the improvement that you would expect to get from transferring some of the workload off of the floorstanders onto the sub(s). So there is much more to the story than meets the eye, and many seem to always want to neglect that by over focusing on flawed theoretical assumptions regarding "directionality" of sounds, etc. etc.
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Post by Gary Cook on Dec 16, 2015 22:10:40 GMT -5
That might be true, to a point - unless the individual who mixes the recording specifically places the LF in one channel (ie mixing the bass guitar or double bass to the far side of the sound stage) like many classic jazz recordings are mixed. Just check my avatar to see where my preference lies. DJ Regardless of how it was mixed, even if the bass below 80 Hz has been recorded to mono, it can still affect the directionality/sound staging. This is because muddy bass has a strong tendency to muddy up the entire sound, and muddy up the spatial cues that are way above 80 Hz. If the bass below 80 Hz has been recorded to stereo, then if it is played back in mono (i.e., played back through a single subwoofer channel, as opposed to a pair of stereo subs), phase cancellations will result from the summing that occurs, thereby causing the bass to be distorted. It is this bass *distortion* that messes up the realistic feel and stereo imaging. Further, on a good pair of big floorstanding loudspeakers the frequency response of which reaches way down to 35 Hz without it producing noticeable distortions, for example, often times you will find that setting the crossover point for your added subwoofer(s) as low as 50 Hz or even lower yields better quality sound in terms of stereo realism than setting it at 60 Hz or higher. An important part of the reason why this can happen is because the crossover region can do more damage to the stereo sound of the floorstanders than the improvement that you would expect to get from transferring some of the workload off of the floorstanders onto the sub(s). So there is much more to the story than meets the eye, and many seem to always want to neglect that by over focusing on flawed theoretical assumptions regarding "directionality" of sounds, etc. etc. All true, but I see an inbuilt assumption that each instrument is miked individually and intern allocated its own mixing channel. Plus one instruments mike does not pick up (out of phase) another instruments sound eg; each instrument is in its own sound proof acoustically dead room with its own microphone. These are rare recording occurrences based on my experiences as it wouldn't sound very "alive". As a result substantial "phase cancellations" may well occur in the recording and the mixing processes. In addition, and possibly more importantly, the listening room acoustics may well cause their own "phase cancellations". Of these, mike, mixing and room acoustics, also occur in a live performance as well as a recorded performance. But in the playing back of a recorded performance there is added room acoustic effect, the listener's room. Having multiple subs does not in itself prevent "phase cancellation", it may well in fact accentuate it. This can be minimised by equalisation but there are side effects from that process that I find unappealing for music. Especially analogue sources that have to go through the ADC DAC processes to be equalised. My view, and it's only my view so not worth much, is that the possible occurrence of mono bass play back "phase cancelation" could easily be completely swamped, to the point of being inaudible, by the multiple other possible occurrences of "phase cancellation". In the real world, my room, with my ears and my equipment a single mono high quality sub consistently outperforms 2, 3 or 4 subs, be it mixed mono or stereo. As a result, although I do recognise the possibility of mono base "phase cancellation", its negative effect is outweighed by its positive benefits. Cheers Gary
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Post by yves on Dec 17, 2015 7:58:42 GMT -5
Regardless of how it was mixed, even if the bass below 80 Hz has been recorded to mono, it can still affect the directionality/sound staging. This is because muddy bass has a strong tendency to muddy up the entire sound, and muddy up the spatial cues that are way above 80 Hz. If the bass below 80 Hz has been recorded to stereo, then if it is played back in mono (i.e., played back through a single subwoofer channel, as opposed to a pair of stereo subs), phase cancellations will result from the summing that occurs, thereby causing the bass to be distorted. It is this bass *distortion* that messes up the realistic feel and stereo imaging. Further, on a good pair of big floorstanding loudspeakers the frequency response of which reaches way down to 35 Hz without it producing noticeable distortions, for example, often times you will find that setting the crossover point for your added subwoofer(s) as low as 50 Hz or even lower yields better quality sound in terms of stereo realism than setting it at 60 Hz or higher. An important part of the reason why this can happen is because the crossover region can do more damage to the stereo sound of the floorstanders than the improvement that you would expect to get from transferring some of the workload off of the floorstanders onto the sub(s). So there is much more to the story than meets the eye, and many seem to always want to neglect that by over focusing on flawed theoretical assumptions regarding "directionality" of sounds, etc. etc. All true, but I see an inbuilt assumption that each instrument is miked individually and intern allocated its own mixing channel. Plus one instruments mike does not pick up (out of phase) another instruments sound eg; each instrument is in its own sound proof acoustically dead room with its own microphone. These are rare recording occurrences based on my experiences as it wouldn't sound very "alive". As a result substantial "phase cancellations" may well occur in the recording and the mixing processes. In addition, and possibly more importantly, the listening room acoustics may well cause their own "phase cancellations". Of these, mike, mixing and room acoustics, also occur in a live performance as well as a recorded performance. But in the playing back of a recorded performance there is added room acoustic effect, the listener's room. Having multiple subs does not in itself prevent "phase cancellation", it may well in fact accentuate it. This can be minimised by equalisation but there are side effects from that process that I find unappealing for music. Especially analogue sources that have to go through the ADC DAC processes to be equalised. My view, and it's only my view so not worth much, is that the possible occurrence of mono bass play back "phase cancelation" could easily be completely swamped, to the point of being inaudible, by the multiple other possible occurrences of "phase cancellation". In the real world, my room, with my ears and my equipment a single mono high quality sub consistently outperforms 2, 3 or 4 subs, be it mixed mono or stereo. As a result, although I do recognise the possibility of mono base "phase cancellation", its negative effect is outweighed by its positive benefits. Cheers Gary If each instrument has been recorded separately, it is up to the mixing engineer to make sure that the end result will contain as little detrimental phase anomalies as possible of course, and this is also part of the reason why the use of quality recording techniques is so hugely important. As an aside, even if instruments are recorded separately, the recording booth isn't always acoustically dead, but you are correct that in this particular recording style [the one that you mention] there can be no phase cancellations picked up by the individual mikes. Rather, these phase cancellations are later added by the mixing console, albeit in a fashion the aim of which is (or at least it should be) to make these phase cancellations inconspicuous. Regardless of that, summing the crossover output of the Left channel and the crossover output of the Right channel into a single subwoofer channel *will* introduce additional phase distortions to an already distorted mix result. Granted, the fact that it's already distorted from the beginning (i.e., due to the mixing) will partially mask the additional distortions so no biggie. However, as has been clearly stated in the article linked in the OP, not all music is recorded this way... (To give you an idea of other possible ways to record stereo, see www.barrydiamentaudio.com/recording1.htm and www.barrydiamentaudio.com/recording2.htm ). As for phase cancellations that occur in-air (be it during recording or during playback), they are a natural part of human everyday life. The brain has received millions upon millions of years training, enabling it to externalize sounds into objects that are generating these sounds, and identify these objects against a typical noise background, or "ambience" of the room that surrounds them. The acoustic reflections and comb filtering that characterize the listening room are an inevitable part of the listening experience, and can *nor should* be eliminated from it. This is what room acoustics and room acoustic treatment is all about. Of course if your room has barely any bass traps, chances are pretty good that you won't be able to hear the benevolent effect of using a good pair of stereo subwoofers. By "good", I don't necessarily mean "expensive", but in my own personal experience, there aren't too many affordable subs out there that won't muck up the sound of a good pair of floorstanding stereo loudspeakers strategically placed in a well treated room regardless of how said subs are integrated. Practically always, the bottom octave is the most expensive one. I know others might disagree, and that's just fine, but my advice boils down to one thing, i.e., don't fall into the common trap of "if it can sound already *this* good, then it must be impossible to achieve sound that is even much better". Audio egalitarians have got no clue. (Nor do people who think that there exists a linear relationship between the quality of a subwoofer and the amount of SPL that it is capable to produce, but I think I'll stop here before it will be all firmly too late once again....).
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Post by jmasterj on Dec 17, 2015 11:44:24 GMT -5
Well I guess it comes down to personal taste, space, and preference. Some have one, some have two or more, and some have none. As long as you like how your system sounds it really doesn't matter.
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Post by yves on Dec 17, 2015 13:32:35 GMT -5
Well I guess it comes down to personal taste, space, and preference. Some have one, some have two or more, and some have none. As long as you like how your system sounds it really doesn't matter. Audio is part science, part subjectiveness so I can't say I completely disagree. If there had existed a standard answer to an audio related question, it would be "It depends". However, if your personal preference is to aim for higher *fidelity* sound, then it really *does* matter quite a bit, and does so without even the slightest imaginable doubt... That said, I don't own any subs because I don't watch a lot of movies anyway, and, for stereo music listening, I have arrived at the sensible conclusion that adding subs to my system as a true meaningful upgrade (i.e., upgrading without mucking up the existing stereo sound too much and up to a point where it should be regarded as merely a side-grade instead of an actual upgrade) is going to cost me well in excess of $8,000 so yes, it's a preference alright. But it's certainly not the kind of ill-informed preference that blatantly contradicts the science part of audio. So it still does matter unless faithful playback of good recordings is not among absolute highest ones on your list of priorities. The physics laws of acoustics still also apply, regardless of how much anyone wants to prefer them not to apply, for example. So it's not exaclty a black or white situation we're talking, but IMO there should be fairly acceptable limits to both sides of the coin, or a thing called "pragmatism". This, of course, is only my own personal opinion, albeit it is still an opinion that tries incredibly hard to make the most logical sense.
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Post by brand on Dec 17, 2015 14:16:39 GMT -5
I will soon have 2 subs, and my preamp is capable of running mono or stereo subs. So, I was doing some research on what is best, and I ran across this. It makes a ton of sense and tends to support my opinions on 2 channel vs. surround etc. Any thoughts? kenrockwell.com/audio/stereo-subwoofers.htmI don't know if this has been mentioned in this thread but please don't ever combine "researching an idea/product" with "kenrockwell.com". My experiences are very much in line with previous posters. I prefer stereo subs although sadly due to space constraints I'm currently not able to run a dual setup.
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Post by yves on Dec 17, 2015 19:28:59 GMT -5
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Post by yves on Dec 17, 2015 20:05:47 GMT -5
I will soon have 2 subs, and my preamp is capable of running mono or stereo subs. So, I was doing some research on what is best, and I ran across this. It makes a ton of sense and tends to support my opinions on 2 channel vs. surround etc. Any thoughts? kenrockwell.com/audio/stereo-subwoofers.htmI don't know if this has been mentioned in this thread but please don't ever combine "researching an idea/product" with "kenrockwell.com". My experiences are very much in line with previous posters. I prefer stereo subs although sadly due to space constraints I'm currently not able to run a dual setup. I just wanted to add that Jim Smith, the author of the book "Get Better Sound", also tends to agree that stereo Left and Right subs helps to improve the depth and imaging in certain stereo music by reducing phase issues. Most of the music cited is classical/pipe organ related.
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Post by jmasterj on Dec 17, 2015 20:32:46 GMT -5
Well I guess it comes down to personal taste, space, and preference. Some have one, some have two or more, and some have none. As long as you like how your system sounds it really doesn't matter. Audio is part science, part subjectiveness so I can't say I completely disagree. If there had existed a standard answer to an audio related question, it would be "It depends". However, if your personal preference is to aim for higher *fidelity* sound, then it really *does* matter quite a bit, and does so without even the slightest imaginable doubt... That said, I don't own any subs because I don't watch a lot of movies anyway, and, for stereo music listening, I have arrived at the sensible conclusion that adding subs to my system as a true meaningful upgrade (i.e., upgrading without mucking up the existing stereo sound too much and up to a point where it should be regarded as merely a side-grade instead of an actual upgrade) is going to cost me well in excess of $8,000 so yes, it's a preference alright. But it's certainly not the kind of ill-informed preference that blatantly contradicts the science part of audio. So it still does matter unless faithful playback of good recordings is not among absolute highest ones on your list of priorities. The physics laws of acoustics still also apply, regardless of how much anyone wants to prefer them not to apply, for example. So it's not exaclty a black or white situation we're talking, but IMO there should be fairly acceptable limits to both sides of the coin, or a thing called "pragmatism". This, of course, is only my own personal opinion, albeit it is still an opinion that tries incredibly hard to make the most logical sense. When I was a little younger there was a phrase that was coined that if memory serves me correctly goes something like this "If you can't dazzle them with your brilliance baffle them with bullshit" That's what came to mind when I read your response to my post. I still say" with clarity for those who my not have understood my point". As long as you like the way your system sounds then it really doesn't matter how many subs you may or may not have.
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Post by yves on Dec 17, 2015 22:37:12 GMT -5
Audio is part science, part subjectiveness so I can't say I completely disagree. If there had existed a standard answer to an audio related question, it would be "It depends". However, if your personal preference is to aim for higher *fidelity* sound, then it really *does* matter quite a bit, and does so without even the slightest imaginable doubt... That said, I don't own any subs because I don't watch a lot of movies anyway, and, for stereo music listening, I have arrived at the sensible conclusion that adding subs to my system as a true meaningful upgrade (i.e., upgrading without mucking up the existing stereo sound too much and up to a point where it should be regarded as merely a side-grade instead of an actual upgrade) is going to cost me well in excess of $8,000 so yes, it's a preference alright. But it's certainly not the kind of ill-informed preference that blatantly contradicts the science part of audio. So it still does matter unless faithful playback of good recordings is not among absolute highest ones on your list of priorities. The physics laws of acoustics still also apply, regardless of how much anyone wants to prefer them not to apply, for example. So it's not exaclty a black or white situation we're talking, but IMO there should be fairly acceptable limits to both sides of the coin, or a thing called "pragmatism". This, of course, is only my own personal opinion, albeit it is still an opinion that tries incredibly hard to make the most logical sense. When I was a little younger there was a phrase that was coined that if memory serves me correctly goes something like this "If you can't dazzle them with your brilliance baffle them with bullshit" That's what came to mind when I read your response to my post. I still say" with clarity for those who my not have understood my point". As long as you like the way your system sounds then it really doesn't matter how many subs you may or may not have. The question is not about whether the OP likes the way his system sounds. Rather, it is about whether it can be possible for him to like the sound better if going for stereo subs, and, regardless of what came to anyone's mind, this is exactly why it does matter. It matters to the OP because else he wouldn't be asking. So your point is still moot, which, also regardless of what came to anyone's mind, brings me back to my own point. I.e., that the benefit of stereo subs is accepted by several many knowledgeable people like professional acoustician Bob Hodas, who has tuned many of the top recording studios in the world, including A&M Studios, Eddy Van Halen's 5150 Studio, Electric Lady Studios, and countless others.
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