Thats why I didn't try it or use it. I refuse to use "black magic" control on a receiver. My model is the VSX-915.
Understandable. I assumed originally that it was a bunch of IIR filters, presumably PEQ's for that matter, that were automatically set to the worst of the peaks, and used only for reduction instead of filling in holes (one could only hope).
Now that I rethink all this, it probably wouldn't be a good thing to use in our type of setup. It probably tests each speaker individually and applies the filters that way. This might be problematic if it tries to apply eq to modes being better corrected by the multiple subs, and it's possible applies it globally in such a fashion that would be problematic in conjunction with the DCX-2496 and multisubs, yet be unfixable. So I guess I can't blame you.
I've been looking at maybe buying the VSX-1120 or since it has the Marvell video processor with QDEO which pioneer implemented so well in their top receiver and bluray player. It has some of the best processing for dealing with noise and artifacts caused by poor transfers or compressed video. Obviously with a great source like a really good bluray, you don't need any of this, and in that case, anything with HDMI switching works. With all the compressed formats I also like to use, having something with some built in processing to fix it up a little helps. The Marvel and VIDI's, fully implemented, have impressed me in demo's, but nobody is implementing them fully in anything affordable.
I've improved the acoustics in my living room quite a bit, but still need more. I'm running out of things I can do until I buy my own place. Which maybe soon, I'm thinking of starting to look next year, and letting my lease go month to month. Full appointment at UIUC, regular salary, will have enough for a down payment and expenses by the time I'm ready, no reason to put it off any longer.
Anyway, I keep wondering if some of these automated digital filter systems could be enough to at least give my primary listening position the best sound possible, without room modifications. I mean, I can't mount acoustic panels over windows, so thick insulated curtains are as good as I can do. External bass trapping has proven near worthless, so not much I can do there. Carpet on the floor helped, especially adding a half inch felt underlayment.
Now that I rethink all this, it probably wouldn't be a good thing to use in our type of setup. It probably tests each speaker individually and applies the filters that way. This might be problematic if it tries to apply eq to modes being better corrected by the multiple subs, and it's possible applies it globally in such a fashion that would be problematic in conjunction with the DCX-2496 and multisubs, yet be unfixable. So I guess I can't blame you.
I've been looking at maybe buying the VSX-1120 or since it has the Marvell video processor with QDEO which pioneer implemented so well in their top receiver and bluray player. It has some of the best processing for dealing with noise and artifacts caused by poor transfers or compressed video. Obviously with a great source like a really good bluray, you don't need any of this, and in that case, anything with HDMI switching works. With all the compressed formats I also like to use, having something with some built in processing to fix it up a little helps. The Marvel and VIDI's, fully implemented, have impressed me in demo's, but nobody is implementing them fully in anything affordable.
I've improved the acoustics in my living room quite a bit, but still need more. I'm running out of things I can do until I buy my own place. Which maybe soon, I'm thinking of starting to look next year, and letting my lease go month to month. Full appointment at UIUC, regular salary, will have enough for a down payment and expenses by the time I'm ready, no reason to put it off any longer.
Anyway, I keep wondering if some of these automated digital filter systems could be enough to at least give my primary listening position the best sound possible, without room modifications. I mean, I can't mount acoustic panels over windows, so thick insulated curtains are as good as I can do. External bass trapping has proven near worthless, so not much I can do there. Carpet on the floor helped, especially adding a half inch felt underlayment.
I have a Yamaha receiver which uses PEQs for automatic correction (YPAO). I don't use that, but I did find them useful for correcting my in-room response in the 125-250 Hz range as well as for slight adjustments in 600-5000 Hz range. The end result was quite good. Unfortunately, the filters are not fully adjustable and there are not quite enough of them - but I was able to make do with it anyway. I think manual filters like this are a useful feature.
I use DRC to derive some very long and complex FIR filters to correct my setup and actually this works extremely well, over quite a large area. That system generates filters with a preference for a single sweet spot, but in my situation at least, the performance is very good over 50% of the width of the room and completely listenable almost everywhere (except literally behind the speakers where the audio goes curiously wierd...)
The correction is full range, so it shouldn't be fooled by your use of multiple subs (or main drivers).
Also of interest should be "Acourate". This is a bit more technical, but might give you more control than you ever wanted. Essentially it uses similar very strong understanding of the ears perception of sound, but more in the form of a "toolkit" and you can use this to design crossovers and filters to suit your needs. For example this system allows creation of extremely advanced phase correct filters and sample perfect alignment of drivers
Yes it's possible to use one of these systems and make everything sound aweful. I don't think that means the whole technology is useless, simply that it's a very powerful tool which needs to be used correctly. It's really no more unusual that tossing a bunch of drivers into a random box sounds less good than a carefully designed system, so likewise an arbitrary filter generator needs to be used with respect
I don't believe that any commercial systems currently come close to the performance of either DRC or Acourate, so don't be misled by the specs on the back of the boxes you currently own... Potentially TACT, DEQX and a couple of other commercial systems get near, but the point is that the filtering on most of these home amps tend to be just a couple of mild notch filters to tame a lively base and make sure all speakers are plugged in right way around (this is the main target...)
The correction is full range, so it shouldn't be fooled by your use of multiple subs (or main drivers).
Also of interest should be "Acourate". This is a bit more technical, but might give you more control than you ever wanted. Essentially it uses similar very strong understanding of the ears perception of sound, but more in the form of a "toolkit" and you can use this to design crossovers and filters to suit your needs. For example this system allows creation of extremely advanced phase correct filters and sample perfect alignment of drivers
Yes it's possible to use one of these systems and make everything sound aweful. I don't think that means the whole technology is useless, simply that it's a very powerful tool which needs to be used correctly. It's really no more unusual that tossing a bunch of drivers into a random box sounds less good than a carefully designed system, so likewise an arbitrary filter generator needs to be used with respect
I don't believe that any commercial systems currently come close to the performance of either DRC or Acourate, so don't be misled by the specs on the back of the boxes you currently own... Potentially TACT, DEQX and a couple of other commercial systems get near, but the point is that the filtering on most of these home amps tend to be just a couple of mild notch filters to tame a lively base and make sure all speakers are plugged in right way around (this is the main target...)
Hmm, is that the same "general consensus" that is buying non horn speakers because of course "horns aren't hifi"? My point being that the general concensus might occur due to regular poor implementations of a potentially good technology?
Here are some thoughts on the likely limits to what you can do electronically.
Room correction limits - DRC
The executive summary is largely as you say, that the correction is most effective as frequency decreases, however, it argues that the effectiveness is not "binary" and it's really on a curve which is a function of frequency. Certainly it would be wrong not to correct electronically at all frequencies, you simply moderate the amount of correction to be a function of frequency (frequency dependent correction seems to have escaped most of the commercial products and probably why many of them either perform poorly, or perpetuate the "truth" the correction should only be done in the bass range)
Anyway, you can't escape that room setup is very important, no one should be arguing that you can turn a rubbish room into a perfect room, only electronically! However, I would claim that it's also very hard and expensive to do all the room correction using only physical changes to the room, and therefore a hybrid of electronic and carefully chosen in room damping is potentially a superb solution...
(Remember that many people make their rooms worse by fiddling with room setup (I'm specifically thinking over damped treble, not enough bass damping) - I don't think it's the case that any of these options is without it's potential flaws?
Anyway, at the level of "DIY Audio" forums I think it's well within many folks here's technical ability to have a go with some electronic room correction to complement their physical room correction.
Good luck
Here are some thoughts on the likely limits to what you can do electronically.
Room correction limits - DRC
The executive summary is largely as you say, that the correction is most effective as frequency decreases, however, it argues that the effectiveness is not "binary" and it's really on a curve which is a function of frequency. Certainly it would be wrong not to correct electronically at all frequencies, you simply moderate the amount of correction to be a function of frequency (frequency dependent correction seems to have escaped most of the commercial products and probably why many of them either perform poorly, or perpetuate the "truth" the correction should only be done in the bass range)
Anyway, you can't escape that room setup is very important, no one should be arguing that you can turn a rubbish room into a perfect room, only electronically! However, I would claim that it's also very hard and expensive to do all the room correction using only physical changes to the room, and therefore a hybrid of electronic and carefully chosen in room damping is potentially a superb solution...
(Remember that many people make their rooms worse by fiddling with room setup (I'm specifically thinking over damped treble, not enough bass damping) - I don't think it's the case that any of these options is without it's potential flaws?
Anyway, at the level of "DIY Audio" forums I think it's well within many folks here's technical ability to have a go with some electronic room correction to complement their physical room correction.
Good luck
ESP 10 KIT
In the interest of DIY, the more a hobbyist can do on his/her own, the better! If you follow the threads here you should know that everyone is stumbling over the geometry of the Wave-Guide, given the box perimeters and only the basic hardware this will satisfy most of us. Many have their cabinets made by others. The waveguIde itself is the 'Brass Ring' so I am sure the kit can be made available without the baffle. This will cut down on initial costs for you in machining, material, machining and shipping. However, I agree with Lsharptec1 options#1 and #3 as maximum!
http://www.diyaudio.com/forums/members/lsharptec1.html
In the interest of DIY, the more a hobbyist can do on his/her own, the better! If you follow the threads here you should know that everyone is stumbling over the geometry of the Wave-Guide, given the box perimeters and only the basic hardware this will satisfy most of us. Many have their cabinets made by others. The waveguIde itself is the 'Brass Ring' so I am sure the kit can be made available without the baffle. This will cut down on initial costs for you in machining, material, machining and shipping. However, I agree with Lsharptec1 options#1 and #3 as maximum!
http://www.diyaudio.com/forums/members/lsharptec1.html
Dr. Geddes,
I've used the search function on the forum, but I haven't been able to find an answer to the following question:
Have you ever considered going 3-way, with one waveguide for the mids and a smaller one for the highs? Although the extra crossover adds complexity and may be (slightly?) detrimental to the sound, the top end could be smoother and constant directivity could be maintained to a higher frequency.
I've used the search function on the forum, but I haven't been able to find an answer to the following question:
Have you ever considered going 3-way, with one waveguide for the mids and a smaller one for the highs? Although the extra crossover adds complexity and may be (slightly?) detrimental to the sound, the top end could be smoother and constant directivity could be maintained to a higher frequency.
Keyser, the directivity of Earl's speakers goes all the way up, how much higher do you want?! The issue is not the top end, but the bottom end, and that is the part that is given up in making the mid smaller. The reason for the 15" driver for the Summa is to get directivity control to a lower point. The other smaller versions are considered more of a compromise.
The argument for smaller drivers is typically wider dispersion and avoiding cone breakup.
The argument for smaller drivers is typically wider dispersion and avoiding cone breakup.
Paul, directivity does collapse a bit in the upper frequency regions:
Occasionally you see 3-ways with a WG for the range from say 800hz to 4 hkz, and another that takes it up from there. I'm not saying this is a better solution per se, I'm just wondering if it has ever been considered or even prototyped.
An externally hosted image should be here but it was not working when we last tested it.
Occasionally you see 3-ways with a WG for the range from say 800hz to 4 hkz, and another that takes it up from there. I'm not saying this is a better solution per se, I'm just wondering if it has ever been considered or even prototyped.
Very high, maybe, but it adds another crossover to go 3-way, and a lot of cost. Crossovers are always the worst part of any design and to minized whenever possible.
Keyser, I think sometimes the eyes are fussier than the ears. You can look at some of these charts, and perfectionism sets in - you want to see a perfect measurement. But what happens if you get there? Does the sound present itself as perfection? Does it sound more real? I think a point is reached where something is "good enough" and sometimes striving to go the next step means doing things that take you one step forward, 3 steps back! Do you then end up with a bigger compromise to fix something that didn't need fixing? That's my take on it.
Active XO via DSP?
Hi Earl, your comments about the crossovers ring very true. Except now there are some great DSP based systems that are pretty affordable and extremely transparent.
For example, have you tried the Behringer DCX2496? It's a pretty great crossover tool. Variable slopes, tons of parametric EQ, variable delay for each channel... the list goes on and on! It's an awesome tool....except the stock analog output section is pretty bad...
BUT...
it can be easily modded to enable direct access to the DAC outputs and then, via good quality film coupling caps or high-grade 1:1 line transformers, the DAC can easily drive most amps directly (works well for loads between 3K ohm and up).
When this mod is done the DCX sounds as good as most $2K DACS... now, couple that with three of the HiFiMeDiy T2 (only $45 each!!) or the Sure electronics amps (also cheap, but very good) and you have a very credible 3 way amplification crossover/system with extremely high levels of transparency and very low distortion...total cost of under $1K for modded DCX with three stereo amps!
Please have a look at these options and tell us what you think, they work really well together.
Hi Earl, your comments about the crossovers ring very true. Except now there are some great DSP based systems that are pretty affordable and extremely transparent.
For example, have you tried the Behringer DCX2496? It's a pretty great crossover tool. Variable slopes, tons of parametric EQ, variable delay for each channel... the list goes on and on! It's an awesome tool....except the stock analog output section is pretty bad...
BUT...
it can be easily modded to enable direct access to the DAC outputs and then, via good quality film coupling caps or high-grade 1:1 line transformers, the DAC can easily drive most amps directly (works well for loads between 3K ohm and up).
When this mod is done the DCX sounds as good as most $2K DACS... now, couple that with three of the HiFiMeDiy T2 (only $45 each!!) or the Sure electronics amps (also cheap, but very good) and you have a very credible 3 way amplification crossover/system with extremely high levels of transparency and very low distortion...total cost of under $1K for modded DCX with three stereo amps!
Please have a look at these options and tell us what you think, they work really well together.
Jack, I believe Earl has used DCX for bass, however, he has also commented in the past that he didn't find any improvement with his speakers when running active, only extra cost. Over two days of listening, I was involved in some listening comparisons of DCX compared to a modded version, MiniDSP and DEQX. You might find it interesting:
Red Spade Audio: Active crossover listening tests
Red Spade Audio: Active crossover listening tests
Dr. Geddes,
By "commercial system," did you mean professional as opposed to home audio or just systems meant to be sold in volume? Pro systems often use active crossovers while home systems rarely do. I suspect that you mean there is no advantage to using active crossovers in a system meant for commercial distribution. Is it fair to say that for the DIYer, there might be a small advantage but still probably not worth the expense? Also I notice that you sub product uses active crossovers (DCX2496).
I meant systems sold in volume.
Things do get more complex when adding in Pro applications because there are other reasons that one might want to use active in Pro. They mostly have to do with improved power handling, which is never an issue in home use - at least not for my designs. I use pro drivers for their low thermal modulation and their ability to get directional coverage. Power handling is not an issue.
For DIY the ease of setup of an active system is an advantage when the system cost is usually far less than the value of the time spent in development.
In my situation, however, the crossover is designed basically automaticaly right off the polar measurements - active actually adds time and complexity to my process. So what works best for me is not necessarily what will work best in all situations. But the bottom line is that active always adds cost and I have found no theoretical reason, nor actual situations in practiced where active should be or is any better than a properly done passive crossover in a home situation.
Passive crossovers for subs are not practical because of the large component values required. Active offers more control, which is needed with multiple subs, and its cost implications are far less because of the component costs of these excessively high value parts. There is a big difference in components for a 1 kHz crossover and a 100 Hz one.
Things do get more complex when adding in Pro applications because there are other reasons that one might want to use active in Pro. They mostly have to do with improved power handling, which is never an issue in home use - at least not for my designs. I use pro drivers for their low thermal modulation and their ability to get directional coverage. Power handling is not an issue.
For DIY the ease of setup of an active system is an advantage when the system cost is usually far less than the value of the time spent in development.
In my situation, however, the crossover is designed basically automaticaly right off the polar measurements - active actually adds time and complexity to my process. So what works best for me is not necessarily what will work best in all situations. But the bottom line is that active always adds cost and I have found no theoretical reason, nor actual situations in practiced where active should be or is any better than a properly done passive crossover in a home situation.
Passive crossovers for subs are not practical because of the large component values required. Active offers more control, which is needed with multiple subs, and its cost implications are far less because of the component costs of these excessively high value parts. There is a big difference in components for a 1 kHz crossover and a 100 Hz one.
I'm considering rebuilding my Nathan kit using polyurethane baffles (as well as another project).
What density of board should I use?
What density of board should I use?
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.