Correction / Equalization Opinions - AVS Forum
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post #1 of 13 Old 11-06-2012, 01:59 PM - Thread Starter
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Go easy on me, I'm new here... smile.gif

I've just finished a remodel of my main listening room, and I'm wanting to make a couple changes/additions to my system to hopefully improve my sound quality a bit.

First off, the room:

Dimentions are roughly a cube: 20x20 feet sqare, just under 22 feet high;
Carpeted (not much help, I know, but every bit counts);
All windows covered with heavy drapes (thermal/insualting style, I live in Alaska);
Furniture is minimal, all upholstered with light fabrics (no leather or microfiber);
Upper portions of high walls have lightweight drapes for acoustic purposes;
One main wall is covered in open-front bookcases (i. e. no glass or cabinet doors);
Original positioning of furniture/equipment was just about optimal before the remodel. This obviously changed when the room was torn up smile.gif

Electronics:

Harman 3490, with a 990 CD player.
Turntable TBD (old one died, must be replaced...That's for adifferent post. *sigh*)
Polk LSi9 speakers, with a Polk PSW12 sub.

No video--I don't own a TV (gasp!) wink.gif

The original setup was tuned using the old Alan Parsons "Sound Check" CD and a multimeter.

The setup I've got gives good quality sound in the room, even considering the relatively large space; I'm not interested in blowing out windows or registering seismic events with a sub, I just want good audio across the board.. Main music types are just about anything you can imagine, from classical to Prog rock, folk, acoustic, everything in between. Only exception is no hip-hop/rap.

Given the changes wrought on the space, I'm considering some options:

1: Upgrade the 3490 to a 990 and use the 990's built-in eq/correction. I'd rather not go this route, as I have a servicable amp and don't need any more power, plus I've heard rumors about issues with the 990's firmware and the amp itself possibly being discontinued in the near future.

2: Keep the 3490 and add a unit like a Behringer DEQ2496 (or even a more basic unit like the 1502) or somesuch that'll let me shape sound a bit better without going overboard. Given that the 3490 doesn't have balanced inputs I'm looking at using RCA-XLR balun cables; Any real gotchas with a setup like this (I've had problems with balanced/unbalanced connections before, though not in audio applications). Also, can a unit like the Behringer safely accept pre-amp input? This isn't a deal breaker, but I'd like to try and get away from using the tape monitor circuits on the amp if possible.

So...Any suggestions? I'd like to keep this as simple as possible, and at the moment I'm doing a lot of playing with different physical room configs, etc. but I'd like the (possible) added bonus of EQ or correction hardware if I want to turn lazy and tweak things further without moving my main listening chair half an inch to the left smile.gif

If you've read this far and aren't bored yet or convinced I'm nuts, many thanks smile.gif

Rob
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post #2 of 13 Old 11-06-2012, 03:38 PM
 
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i'm convinced you are nuts.
the amp says something about being of audiophile quality.
and you want to spend more money on a piece of hardware, when you already using a computer powerful enough to do that for you.
are you on the computer at the library or some kiosk?

equalizing only has the few options:
1. use whatever tone controls are on the receiver|amp
2. use any of the built-in audio effects or automatic equalizers to get the frequency response more flat
3. use a seperate solution

the seperate solutions are:
1. software equalizer .. the old-school manual ones arent all that easy or impressive
2. the hardware equalizers .. these arent easily found or impressive, and they dont advertise anything about being able to keep up with the sound quality from your receiver
3. using a computer to load up some VST plugins and get the audio sent out of the computer to the amplifier (this comes with added benefits like being able to watch a movie from the cheaper blu-ray rom drive = saves money and does more needed functions)

many people havent heard the audio upgrades from leaving 16bit behind and going up to 24bit.
but that is the biggest step and the thing all of us audio people are thirsty for.
there's just a whole bunch more audio pouring out of the speaker cones with 24bit audio .. and then the compressed files would sound better because there is more content inside of the file pouring out more from the speaker cones than they do today.

some of those chips on the soundcards have been laying there waiting to be activated.

i would expect a built-in equalizer to do a solid job.
but the target curve might not be flat, and if the frequency response isnt clamped down tight as the final result.. then the toy isnt as serious as the dedicated tools to get it done.
maybe those two things are ment to work together to get the best result from the amplifier..?!!

how you put those pieces of legos together is your game.
there are better options than others.
maybe cheaper alternatives that give a large improvement too.

a long graphic equalizer and some impulse response files from the microphone would do any system justice.
try finding those as dedicated hardware solutions and you will probably feel like you are being laughed at and tormented.
either solution is limited by the computer software used to record the results .. because they use presets that dont allow adjustment, and after much time and consideration .. the results they give are the decisions people live with.


the only way it can get better from a solid soundstage is to make that solid soundstage perform with more depth.
that is most often done with spatial image processing.

those 4 ohm speakers arent helping your ampllifier with the distortion numbers on the tech spec sheet.
0.2% compared to 0.07% is a large difference .. like new speaker difference.

you should at least do yourself the favor and try building your own speaker from raw parts .. an 8 ohm speaker and disconnect all the other speakers and plug that one in and see if you can hear the lack of distortion.
chances are, if you build a real speaker that you would want to build another and replace those polk speakers for something of an improvement.. then you will probably hear those differences as you move up the line of fidelity.
but if you build something cheap to simply skip a meal and call it done .. then chances are you might not hear the difference.

maybe you simply get one of those 'high-grade' midranges and a crossover and listen from the crossover and midrange connected to learn of any improvement.

i could always tell the difference between the total harmonic distortion percentage in stereo compared to switching the amp to surround sound.. and my speakers are from the early 1990's

it's been about 20 years since my speakers were released .. i dont see why you couldnt hear a difference with your speakers at home, except that they are stuck in 4ohm.
maybe you wire them up in series to try and learn .. but half the signal to one speaker and half the signal to the other speaker is an engineers toy to show you it can be done .. and that means dont expect fair results if you tried.
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post #3 of 13 Old 11-06-2012, 05:18 PM - Thread Starter
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Well OK, sounds like I'm off my rocker...

To your first point, I'm not even using a computer at the moment. Thanks for that bit of snark.

Second, where did I say I want or need (let alone *have*) a computer to hook into my crummy setup? I don't. I'm just a guy who likes his CDs, and has a decent room and enough gear to want them to sound good.

THD on the speakers was known to me when I bought them. If it mattered to me that much I wouldn't have wasted your time posting a question.

To top it off you didn't even address my main points: Room config, hardware brand and/or function, or how to improve on what I've already got, except to slam me as needing a lesson in how to build speakers.

You also missed (or ignored) that I have no video setup--so why bother with even bringing that up?

Respones like these are why I hate going online for help. All I did was ask a simple question, and got a "bad little boy who needs a lesson" talking-to.

You go enjoy your Uber-audio. I'll enjoy my inferior garbage, and skip the AVS forums from now on.

What a colossal waste.
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post #4 of 13 Old 11-06-2012, 06:20 PM
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Quote:
Originally Posted by ecouter View Post

Go easy on me, I'm new here... smile.gif
No worries smile.gif. Watching the elections as I type this so good way of passing the time smile.gifsmile.gif.
Quote:
Carpeted (not much help, I know, but every bit counts);
On the contrary, it counts for a lot! Carpet covers lots of area so it is very helpful in containing mid to late reflections. Hoping it has thick padding, you are doing good there.
Quote:
All windows covered with heavy drapes (thermal/insualting style, I live in Alaska);
Another excellent thing. Heavy drapes act as good broadband absorbers.
Quote:
Furniture is minimal, all upholstered with light fabrics (no leather or microfiber);
Upper portions of high walls have lightweight drapes for acoustic purposes;
One main wall is covered in open-front bookcases (i. e. no glass or cabinet doors);
Bookcases nicely scatter sound waves. Assuming all the walls are not covered, are doing very well in controlling mid to late reflections.
Quote:
1: Upgrade the 3490 to a 990 and use the 990's built-in eq/correction. I'd rather not go this route, as I have a servicable amp and don't need any more power, plus I've heard rumors about issues with the 990's firmware and the amp itself possibly being discontinued in the near future.
2: Keep the 3490 and add a unit like a Behringer DEQ2496 (or even a more basic unit like the 1502) or somesuch that'll let me shape sound a bit better without going overboard. Given that the 3490 doesn't have balanced inputs I'm looking at using RCA-XLR balun cables; Any real gotchas with a setup like this (I've had problems with balanced/unbalanced connections before, though not in audio applications). Also, can a unit like the Behringer safely accept pre-amp input? This isn't a deal breaker, but I'd like to try and get away from using the tape monitor circuits on the amp if possible.
So...Any suggestions? I'd like to keep this as simple as possible, and at the moment I'm doing a lot of playing with different physical room configs, etc. but I'd like the (possible) added bonus of EQ or correction hardware if I want to turn lazy and tweak things further without moving my main listening chair half an inch to the left smile.gif
If you've read this far and aren't bored yet or convinced I'm nuts, many thanks smile.gif
Rob
The Behringer path requires learning to measure your room response and then manually optimizing. If you are up for that, and can correctly integrating it into your signal path, then it is a good option. You can even just run your sub through it which should be very easy. The room impacts the low frequencies the most and that is where you want to use the EQ to knock off the peaks (see my article here: http://www.madronadigital.com/Library/BassOptimization.html). If learning what to do is hard, then upgrading to a unit with Auto EQ is wise. These can sometimes degrade the sound but odds are good that they will do good.

You are definitely asking the right questions and not nuts smile.gif. Cutting through online folklore can be hard though as you have just found out smile.gifsmile.gif.

Amir
Retired Technology Insider
Founder, Madrona Digital
"Insist on Quality Engineering"
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post #5 of 13 Old 11-06-2012, 07:00 PM
 
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Originally Posted by ecouter View Post

so why bother with even bringing that up?

the difference between 20 and 7 is 13 = almost double..!

**edit**

what do you want to talk about?
is it because you dont want to do it alone?, because i had to change a headlight in the rain today all alone.

are you asking about right from wrong?
as if it hasnt already been talked about when comparing reasons to use suggestions, and reasons to go the alternative route.
as if it wasnt me going in there saying it .. i just think maybe you threw yourself as me being a person that talks and leaves the response empty .. because to the contrary, i've said a bunch of valuable information in a week than i've seen in a month.


a bit personally upset?
maybe the amplifier has more slew at 0.2% distortion.
it is there in your room, you can touch it .. just thought maybe you would want to ask it a question rather than let it lead your life.
because either you lead it or it leads you.

people come to the forum trying to gain the lead advantage, and it is the same exact rules each time the subject matter comes back up.
there is zero reason to repeat yourself multiple times in a month , only to repeat the process for a whole year .

i dont think you gave me enough sincere credit about rational thought.
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post #6 of 13 Old 11-07-2012, 07:30 AM
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Quote:
Originally Posted by ecouter View Post

Go easy on me, I'm new here... smile.gif

First off, the room:

Dimentions are roughly a cube: 20x20 feet sqare, just under 22 feet high;
Carpeted (not much help, I know, but every bit counts);
All windows covered with heavy drapes (thermal/insulating style, I live in Alaska);
Furniture is minimal, all upholstered with light fabrics (no leather or microfiber);
Upper portions of high walls have lightweight drapes for acoustic purposes;
One main wall is covered in open-front bookcases (i. e. no glass or cabinet doors);
Original positioning of furniture/equipment was just about optimal before the remodel. This obviously changed when the room was torn up smile.gif

Neither drapes nor carpeting are high-effectiveness, broadband absorbers.

With a room that is such a perfect cube, its hard to imagine how room response through the bass frequencies is anything like optimal.

If you are serious about sound quality, and particularly if you go the equalizer route, you should invest in some acoustics measurement equipment and softwaare. Check the "Room Eq Wizard" thread for more info about that.
Quote:
Electronics:

Harman 3490, with a 990 CD player.
Turntable TBD (old one died, must be replaced...That's for adifferent post. *sigh*)
Polk LSi9 speakers, with a Polk PSW12 sub.

Not bad! I wouldn't change a thing until I knew a good reason why.

I'm considering some options:
Quote:
1: Upgrade the 3490 to a 990 and use the 990's built-in eq/correction. I'd rather not go this route, as I have a serviceable amp and don't need any more power, plus I've heard rumors about issues with the 990's firmware and the amp itself possibly being discontinued in the near future.


I agree with your thinking. the 3490 has pre amp out/ amp in jacks, so you have very many options - basically the same options you'd have if you had separates.

Quote:
2: Keep the 3490 and add a unit like a Behringer DEQ2496 (or even a more basic unit like the 1502) or somesuch that'll let me shape sound a bit better without going overboard. Given that the 3490 doesn't have balanced inputs I'm looking at using RCA-XLR balun cables; Any real gotchas with a setup like this (I've had problems with balanced/unbalanced connections before, though not in audio applications). Also, can a unit like the Behringer safely accept pre-amp input? This isn't a deal breaker, but I'd like to try and get away from using the tape monitor circuits on the amp if possible.

Zillions of people have interfaced pro gear with balanced I/O including the DEQ 2496 to consumer receivers and the like (including me!) and its usually pretty easy, cable-wise. I've gotten away with just using off-the-shelf RCA to XLR adapter plugs on occasion.

I think that getting into the world of more serious audio measurements is your first logical step.

I suspect that acoustic measurements will give you adequate stimulation and guidance in terms of your next steps with room acoustics and equalization. I suspect you will end up making significant moves in both areas.

BTW congratulations at stepping over the %$#@@ post, above. Nice job! ;-)
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post #7 of 13 Old 11-07-2012, 10:29 AM
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Originally Posted by arnyk View Post

Neither drapes nor carpeting are high-effectiveness, broadband absorbers.

With a room that is such a perfect cube, its hard to imagine how room response through the bass frequencies is anything like optimal.

If you are serious about sound quality, and particularly if you go the equalizer route, you should invest in some acoustics measurement equipment and softwaare. Check the "Room Eq Wizard" thread for more info about that.

I suspect that acoustic measurements will give you adequate stimulation and guidance in terms of your next steps with room acoustics and equalization. I suspect you will end up making significant moves in both areas.

I have nothing to add other than to say this is the correct advice.

--Ethan

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Ethan's Audio Expert book

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post #8 of 13 Old 11-07-2012, 12:48 PM - Thread Starter
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Quote:
Originally Posted by arnyk

I think that getting into the world of more serious audio measurements is your first logical step.

I suspect that acoustic measurements will give you adequate stimulation and guidance in terms of your next steps with room acoustics and equalization. I suspect you will end up making significant moves in both areas.
Quote:
Originally Posted by Ethan Winer

I have nothing to add other than to say this is the correct advice.

--Ethan

Thanks guys for these suggestions. The major issues I'm having at the moment are with the extreme low end, most likely exacerbated by the fact that the room is shaped so "perfectly' and also sits atop a roughly 5-foot deep crawlspace that gives me truly awful resonance.

From a sound quality perspective (as perceived by my ears, of course...) things aren't too bad as they are, until the trouble arrives below about 150Hz with lots of harmonics and hot spots in the room. It's actually pretty easy to tell where some of the substructure of the crawlspace/foundation is located just by moving around and listening to the changes in sound, or in the case of the sub feeling the vibration change in different sections of the floor. From what my ears tell me (which I admit may be totally wrong smile.gif ) this seems to be a structural resonance problem rather than reflections coming from wall coverings, furniture, and the like as I get much worse artifacts in areas that are clear spans vs. being close to vertical supports or the outer walls of the foundation. The fun part will be mitigating the problem smile.gif
Quote:
Zillions of people have interfaced pro gear with balanced I/O including the DEQ 2496 to consumer receivers and the like (including me!) and its usually pretty easy, cable-wise. I've gotten away with just using off-the-shelf RCA to XLR adapter plugs on occasion.

Thanks for this Arny, that helps. Regarding this point: Obviously no strictly electronic solution will be the end-all-be-all solution, but my idea for the EQ portion of things was to use it in conjunction with physical changes to make the arrangement and shaping of the room and furnishings at least easier. I'm not tied to any one particular brand, but having seen the Behringer products mentioned here in other threads made me check those out first. The DEQ2496 seems to have some features that might make analysis easier on down the line, what do you think?

One question...I'm assuming none of us is a structural engingeer here, but if after some audio analysis this really does turn out to be a major issue with vibration in less supported areas of the structure, what kinds of options are there for physically damping down the motion (or simulating a physical change electronically)? The walls and crawlspace are insulated with urethane foam, which I suppose could be applied to other parts of the structure like floor joists, but I'm wondering if a solution could be as potentially simple as just placing a piece of furniture in the right spot to dampen some floor movement...

Thanks again for the good suggestions and help...Will keep you advised as to what I hear (pun fully intended) smile.gif

Rob
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post #9 of 13 Old 11-07-2012, 04:01 PM
 
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Originally Posted by ecouter View Post

Thanks guys for these suggestions. The major issues I'm having at the moment are with the extreme low end, most likely exacerbated by the fact that the room is shaped so "perfectly' and also sits atop a roughly 5-foot deep crawlspace that gives me truly awful resonance.

i stopped here and said 'i am not convinced' because i would be using that loose floor to my advantage .. never seen wood slide on a nail before?.

**edit**

a jack of all trade would mob up and tell you how to save your house by checking the floor for nails or screws.
..and if you dont own the floor,
more power to the landlord.


..edit..

...wait, i'm going back to read it some more.



....................
an equalizer is going to find a ring of the room and cause the whole room to pressurize with the different springs needing to be viewed more like a single spring that all the knobs aim for.
kinda like a donut with a hole, but the ring of the room fills the hole.


then you could do the impulse response inversion to make the pressure clean itself up .. not only with sound shaping, but sound timing.

from there you can fill in the lines created with the impulse response.
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post #10 of 13 Old 11-07-2012, 04:17 PM
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Originally Posted by ecouter View Post


Thanks for this Arny, that helps. Regarding this point: Obviously no strictly electronic solution will be the end-all-be-all solution, but my idea for the EQ portion of things was to use it in conjunction with physical changes to make the arrangement and shaping of the room and furnishings at least easier. I'm not tied to any one particular brand, but having seen the Behringer products mentioned here in other threads made me check those out first. The DEQ2496 seems to have some features that might make analysis easier on down the line, what do you think?

The reputation of the the DEQ2496 as a useful tool is excellent.
Quote:
One question...I'm assuming none of us is a structural engingeer here, but if after some audio analysis this really does turn out to be a major issue with vibration in less supported areas of the structure, what kinds of options are there for physically damping down the motion (or simulating a physical change electronically)? The walls and crawlspace are insulated with urethane foam, which I suppose could be applied to other parts of the structure like floor joists, but I'm wondering if a solution could be as potentially simple as just placing a piece of furniture in the right spot to dampen some floor movement...

I think you are over-thinking the problem. Get your measurement facility working, and see what is really going on with your room!

It turns out that rooms with very rigid walls and floors (masonry, either concrete or wet plaster) are acoustically disadvantageous. A certain amount of "give" is a good idea. Also, the sonics of your room will benefit from some diffusion.
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post #11 of 13 Old 11-07-2012, 04:22 PM
 
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...roll the phase down, then grab your impulse response files .
roll it down until it floods the room as one note or pressure .

there's a whimper example at master of bachelor art.

or layer your impulse response files until the room changes phase until one note .
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post #12 of 13 Old 11-07-2012, 04:49 PM
 
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..you dont need that much pressure in the room.
but if you calibrate that pressure, it will do magic tricks for you .
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post #13 of 13 Old 11-07-2012, 05:38 PM - Thread Starter
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Quote:
Originally Posted by arnyk

The reputation of the the DEQ2496 as a useful tool is excellent.

Good to know. Thanks. smile.gif
Quote:
I think you are over-thinking the problem. Get your measurement facility working, and see what is really going on with your room!

Over-thinking is my specialty smile.gif I was more curious as to the wide variance in the perceptible vibrations in the floor and whatnot than anything else. Good sturdy walls are always a plus, but just as with audio anywhere, up here in earthquake country you've got to walk that line between strong and stiff and loose and flexible, or you'll end up involuntarily living in a tent one day smile.gif The last thing you want is a building that can't roll with it a bit...

Thanks again for the advice. I'll get some measurements and see what's really going on down there...

Rob
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