Downstairs:
Denon 2803, some amps and speakers
Two 15" Quatros in ported enclosures, with PE 240 watt plate amps
Upstairs:
Rotel preamp, Hafler DH-200 amp, magneplanar MMGs
Just gave my little Parts Express DLS-10 sub to a friend who is setting up a small basement HT.
I've got four more Quatros in their cardboard boxes in a closet, along with four of the recent audiosource MCM buyout plate amps....
Here's what I'm thinking...
The maggies would really like sub(s). I'm figuring on building a pair sealed, 3.5 cubes. They're going to get the two PE plate amps that are currently running the basement.
In the basement, I'm going to run the sub out, and split it, to a Hafler DH-500 (250 into 8, stable into 4) and use that to drive the subs. Thing is, is there a way to easily play with the crossover zone, like one can with sub amps? Without spending a bundle of money, and time, on inductors and solder?
Basement 95% movies/rock and roll concert movies, upstairs is mostly jazz and blues.
Denon 2803, some amps and speakers
Two 15" Quatros in ported enclosures, with PE 240 watt plate amps
Upstairs:
Rotel preamp, Hafler DH-200 amp, magneplanar MMGs
Just gave my little Parts Express DLS-10 sub to a friend who is setting up a small basement HT.
I've got four more Quatros in their cardboard boxes in a closet, along with four of the recent audiosource MCM buyout plate amps....
Here's what I'm thinking...
The maggies would really like sub(s). I'm figuring on building a pair sealed, 3.5 cubes. They're going to get the two PE plate amps that are currently running the basement.
In the basement, I'm going to run the sub out, and split it, to a Hafler DH-500 (250 into 8, stable into 4) and use that to drive the subs. Thing is, is there a way to easily play with the crossover zone, like one can with sub amps? Without spending a bundle of money, and time, on inductors and solder?
Basement 95% movies/rock and roll concert movies, upstairs is mostly jazz and blues.
I belive your answer is in what one would call an electronic crossover. This would be installed in the signal chain before the sub amp.
I assume you were refering to not having to play with inductors in the sub cabinet. Inductors are a last resort for most folks. They take a great deal of power/waste power in order to provide a filter with a 6db per octave slope.
I assume you were refering to not having to play with inductors in the sub cabinet. Inductors are a last resort for most folks. They take a great deal of power/waste power in order to provide a filter with a 6db per octave slope.
About 3:00 ay-bleepin-em, it came to me...
I'm _already_ using a Behringer Feedback Destroyer as a parametric equalizer... I'll just do a couple of major wide cuts higher, and not worry about it.
Sound good?
I'm _already_ using a Behringer Feedback Destroyer as a parametric equalizer... I'll just do a couple of major wide cuts higher, and not worry about it.
Sound good?
Sound good?
No, I would take the Behringer out and set it on the shelf. I sincerely doubt there is a need for a parametric Eq in your system.
Sell it and get a good crossover. Just my .02
No, I would take the Behringer out and set it on the shelf. I sincerely doubt there is a need for a parametric Eq in your system.
Sell it and get a good crossover. Just my .02
burnedfingers said:
Even if a subwoofer has a nice even response free field, it is at the mercy of room boundaries in an actual setup. So, without knowing the specifics of a setup, measurements and all, I would be hesitant to say that the bass region is not in need of equalization, regardless of loudspeaker used to produce it.
/Kranis
A quality parametric equalizer is necessary in most practical rooms to get as close to an even bass response as possible.
Dr. Floyd Toole, one of the original NRC acoustics researchers, has a great paper discussing the physics of bass in real rooms:
http://www.harman.com/wp/pdf/Loudspeakers&RoomsPt3.pdf
What's particularly valuable in that paper are the worked examples of real rooms.
Dr. Floyd Toole, one of the original NRC acoustics researchers, has a great paper discussing the physics of bass in real rooms:
http://www.harman.com/wp/pdf/Loudspeakers&RoomsPt3.pdf
What's particularly valuable in that paper are the worked examples of real rooms.
Unless you have about 6) calibrated microphones a summing network and a program similar to what JBL uses to setup their synthsys systems why bother?
The correction would only be valid in one point in the room. The problem lies in the time domain and this cannot be corrected with an equalizer.
None of the DSP systems work either.
Have you ever listened to a system that has been eq'd and notice that all the life is gone.
The correction would only be valid in one point in the room. The problem lies in the time domain and this cannot be corrected with an equalizer.
None of the DSP systems work either.
Have you ever listened to a system that has been eq'd and notice that all the life is gone.
Those are the folks who usually hit it way too hard...
A few mild adjustments here and there shouldn't cause a problem. I got the BFD to mess with a peak, and to also run a set of transducers through... When I have a movie night, my friends tend to want to sit on the white sofa... I wanted to do some cutting to remove a lot of the higher stuff, so that music, etc., wasn't gonna make the sofa shake, but emphsize from about 45-50hz on down. Seems to be working, and nothing's smoked yet...
I'm just going to move the two 240 watt plate amps upstairs, and run the two 4 ohm subs off the Hafler.
A few mild adjustments here and there shouldn't cause a problem. I got the BFD to mess with a peak, and to also run a set of transducers through... When I have a movie night, my friends tend to want to sit on the white sofa... I wanted to do some cutting to remove a lot of the higher stuff, so that music, etc., wasn't gonna make the sofa shake, but emphsize from about 45-50hz on down. Seems to be working, and nothing's smoked yet...
I'm just going to move the two 240 watt plate amps upstairs, and run the two 4 ohm subs off the Hafler.
burnedfingers said:
I am not convinced that we are talking about the same thing here. I for one agree that correcting room modes over 200 Hz is of questionable value: the area of correction will be too limited. Still, room modes (as in "standing waves") in the bass region (say less than 120 Hz or where your subwoofer happens to be active) are very susceptable to equalization, especially if you place the subwoofers in corner where they are guaranteed to excite all the room modes. Although the correction as you say canonly be right in "one spot", that "spot" will be quite a substantial area when the wavelenghs are long. If this area happens to be the sofa where one sits, the value should be obvious. The alternative is to move the furniture to suit the acoustics. Another advantage of the equalizer compared to adjusting the listening position, is that when peaks are reduced, it saves amplifier power.
/Kranis
I believe we are talking about Eqing the subwoofer output. I believe that you have the idea that eqing the output is a cureall for the room imperfections and standing waves. As one who is experienced in this field I have had to perform the setup of theatre systems(JBL) in order for their certification. It is interesting to eq a room using their calibrated microphones at their setup positions in order to reach the desired goal per their guidelines. It is also interesting to shift the positions of the microphones and note the differences caused by their movement. Therefore your idea of eqing based on one microphone or maybe your ear doesn't hold much promise in my opinion. If you can convience yourself that you have indeed done something constructive then by all means pat your self on the back because you deserve it. I deal in date obtained by using the correct equipment and procedures. I question your results and how they are obtained.
No, it do not believe it is a cureall, only that it may have value to reduce peaks (and to a lesser extent dips) in the room response at the listening position. If you have to have a wider area in which you need an even response, as in a theatre, you will need other tools. Of courseburnedfingers said:
The question of multiple test points makes sense when the eq'ing is done over a wide area or when eq'ing is done at such high frequencies that direction becomes an issue. As for the questioning of results, the O'Toole piece seems to state precisely what your are objecting to. So, taking this document as a starting point, could you point out where he is in error.
I am not part of the "DSP it away" brigade. But neither am I prepared do deny the value of parametric eq'ing either.
Sincerely,
Kranis
Parametric EQ is of great help in taming subwoofer-frequency room modes.
Burnedfingers, you seem to criticize anything that does not use megabuck pro equipment. I think we would all like the option of using FIR filters and room compensation, with the benefit of a powerful processor and multiple test mics. In reality, few can afford it.
This is DIY audio--we find a way to extract maximum value from what we can afford. There are people making comparitively great sounding speakers every day for $10-$50. Just because they aren't as good as a $10,000 speaker could be doesn't mean they aren't worth doing.
Burnedfingers, you seem to criticize anything that does not use megabuck pro equipment. I think we would all like the option of using FIR filters and room compensation, with the benefit of a powerful processor and multiple test mics. In reality, few can afford it.
This is DIY audio--we find a way to extract maximum value from what we can afford. There are people making comparitively great sounding speakers every day for $10-$50. Just because they aren't as good as a $10,000 speaker could be doesn't mean they aren't worth doing.
burnedfingers said:
I don't know how many times I have called Floyd Toole "O'Toole". If it is Freudian, I don't know what to make of it although O'Toole's (Peter) eclectic work has always appealed to me. However, I assume you meant that Toole's (Floyd) work was not of any value (and I give you the benefit of the doubt that this statement was limited to this specific HK while paper). While I most certainly do not agree with this opinion, it did make your position very clear and saves this thread from further argument on a topic for which there apparently is no prospect of reaching a common understanding.
To Bogie: Yes, I thought you nocturnal idea it sounded good, at least for starters. A dedicated crossover adapted to your set-up may have the potential to provide a more precisely controlled amplitude and phase response in the crossover region, but at a cost. In addition, a crossover will also save your tops from receiving unwanted low frequency energy. However it needs to be "active" i.e. electronics inserted before the power amps. Making a low-pass filter for a sub is more or less doomed since the driver will be anything but an ohmic resistance in the crossover region. And even if you would pull it off, the hardware alone could cost you in the vicinity of an electronic crossover, would waste a lot of power and have a shallow slope. Good luck with your experiments.
Sincerely,
Kranis
burnedfingers said:
I don't intend to start a flame war with you (there are already far too many on this board), but this comment is somewhat humorous.
Dr. Toole has, over the last thirty years, published an enormous number of peer-reviewed academic papers on the science of acoustics. He helped get the very influential NRC acoustics research center in Ottawa going in the 70s. He has made significant contributions to the field of loudspeaker science, including things we now take for granted, such as the studies showing the importance of having an even off-axis response. This is hardly someone who's work has been of no value.
Well, I don't care who he is. These are my speakers, not his...
(got the MDF cut today - gettin' ready to commence gluin' and screwin'...)
Time to go check the weather station, and see if it'll be warm enough to fire up the router tomorrow...
(got the MDF cut today - gettin' ready to commence gluin' and screwin'...)
Time to go check the weather station, and see if it'll be warm enough to fire up the router tomorrow...
Eh?
Bogie,
I didn't realize routers had a minimum operating temperature! You learn something every day.
As for playing around with the crossover frequency on your basement system, here's the scoop. As you say you are splitting the sub output from the Denon AVR2803, you've already got a crossover, presumably fourth order, but non-adjustable, right? The only way to get an adjustable frequency is to not use the subwoofer output, but instead use the front L/R preouts (therefore, set Sub = No, forcing front L/R to large in the Denon's setup). You'll now have a full range preout, in stereo actually, which is not a problem since you will have two subwoofers and two amp channels. Then you just need to insert the crossover of your choice between the AVR2803 and your sub amps. Behringer makes one that sells for under $100 I believe (CX2310 or something), there are others as well. The only problem I possibly forsee is that some receivers actually disengage the front L/R speaker outputs when you use the front L/R preouts. I don't know if Denon does this. Also, you'd be sending full range to your fronts. No way around that unless you get another amp for the front L/R to put after the high pass section of whichever outboard crossover you use. Now, you COULD in theory cascade an external crossover on the Denon's sub output, but this is of questionable value and use, since all you really would be doing is increasing the slope above the Denon's sub crossover point.
Out of curiosity, have you tried just using the crossover built into your Denon receiver? It's likely 80-100 Hz 24 dB/octave. With two subwoofers placed near the mains, this crossover should present little problem?? I don't have any issues with my Quatro crossed at 80 Hz, 24 dB/octave.
Aaron Gilbert
Bogie,
I didn't realize routers had a minimum operating temperature! You learn something every day.
As for playing around with the crossover frequency on your basement system, here's the scoop. As you say you are splitting the sub output from the Denon AVR2803, you've already got a crossover, presumably fourth order, but non-adjustable, right? The only way to get an adjustable frequency is to not use the subwoofer output, but instead use the front L/R preouts (therefore, set Sub = No, forcing front L/R to large in the Denon's setup). You'll now have a full range preout, in stereo actually, which is not a problem since you will have two subwoofers and two amp channels. Then you just need to insert the crossover of your choice between the AVR2803 and your sub amps. Behringer makes one that sells for under $100 I believe (CX2310 or something), there are others as well. The only problem I possibly forsee is that some receivers actually disengage the front L/R speaker outputs when you use the front L/R preouts. I don't know if Denon does this. Also, you'd be sending full range to your fronts. No way around that unless you get another amp for the front L/R to put after the high pass section of whichever outboard crossover you use. Now, you COULD in theory cascade an external crossover on the Denon's sub output, but this is of questionable value and use, since all you really would be doing is increasing the slope above the Denon's sub crossover point.
Out of curiosity, have you tried just using the crossover built into your Denon receiver? It's likely 80-100 Hz 24 dB/octave. With two subwoofers placed near the mains, this crossover should present little problem?? I don't have any issues with my Quatro crossed at 80 Hz, 24 dB/octave.
Aaron Gilbert
Quote:
I don't intend to start a flame war with you (there are already far too many on this board), but this comment is somewhat humorous.
Unfortunately many people believe everything they read and it seems that you fall into this catagory. However, I will not find your comments humorous. I will however respect your views as you should mine.
I should maybe backtrack and state that I do not hold true all of Mr. O'Toole's work. There are selected areas where his work is correct and others where it is questionable. Mr. O'Toole was employed by Harmon and his work in my opinion reflects this.
Unfortunately anyone can write a paper and more unfortunate that others read and believe what has been stated without proof.
I could go into detail with about 5 or 6 pages and bore you to death but then you will still go on thinking what you want so I will not bother.
The "Q" of your crossover.
Do you know the electrical parameters of your driver? What is its "Q"? What is the "Q" of the crossover in the Denon? The "Q" of the crossover in the Denon will have a direct effect on the output/sound of your sub. Cascading crossover sections without knowing the "Q's" of each section can bring on very bad results.
Maybe with your knowledge you are already ahead of me and know this. In this case please excuse me.
I don't intend to start a flame war with you (there are already far too many on this board), but this comment is somewhat humorous.
Unfortunately many people believe everything they read and it seems that you fall into this catagory. However, I will not find your comments humorous. I will however respect your views as you should mine.
I should maybe backtrack and state that I do not hold true all of Mr. O'Toole's work. There are selected areas where his work is correct and others where it is questionable. Mr. O'Toole was employed by Harmon and his work in my opinion reflects this.
Unfortunately anyone can write a paper and more unfortunate that others read and believe what has been stated without proof.
I could go into detail with about 5 or 6 pages and bore you to death but then you will still go on thinking what you want so I will not bother.
The "Q" of your crossover.
Do you know the electrical parameters of your driver? What is its "Q"? What is the "Q" of the crossover in the Denon? The "Q" of the crossover in the Denon will have a direct effect on the output/sound of your sub. Cascading crossover sections without knowing the "Q's" of each section can bring on very bad results.
Maybe with your knowledge you are already ahead of me and know this. In this case please excuse me.
I've currently got the Denon crossed at 60hz, for the center and the surround backs... Everything else is set as "large."
Fronts are running through a Hafler DH-500 amp, and the sides through a Hafler DH-225.
Beware - you've given me an idea... I suppose I could probably switch the sides to "small," the sub configuration to "sub + mains" and then use a crossover to add another pair of subs (or two...). Heh, heh, heh...
Fronts are running through a Hafler DH-500 amp, and the sides through a Hafler DH-225.
Beware - you've given me an idea... I suppose I could probably switch the sides to "small," the sub configuration to "sub + mains" and then use a crossover to add another pair of subs (or two...). Heh, heh, heh...
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