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Equalization with Loudspeakers. Not with PC as source. - Page 3

post #31 of 37
2/13/08 at 4:38am
Quote:
Originally Posted by sejarzo View Post
You really do not want your room dead flat. If you adjust it that way, it will sound almost as if you've sucked all the bass out and have two AM radios sitting there instead of your speakers!
I've had the same problem with auto EQ. It has to do with the difference between flat to the ears and flat to the mike. If you do a sweep and balance by ear, the bass will be just as full and even as the upper ranges.

See ya
Steve
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post #32 of 37
2/13/08 at 4:54am
Steven

Copland makes a device that does that. I think Audio Connection in Sydney had one 2nd hand

Stewart
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post #33 of 37
2/13/08 at 5:46am
Thread Starter 
Quote:
Originally Posted by sejarzo View Post
...
Thanks for all that info, I'm happy to pay $40 to get what I need, if I need it. I'll look into it.

The problem is my PC is in another room, the case weighs over 60 pounds (30KG) and it's a pretty permanent install. I don't have a laptop but have been thinking maybe I need one...

If I really need to (and it seems I do) I will relocate the PC to the loungeroom for the equalizing but I'll get well organized first.

This is the SPL meter I have here:

Jaycar Electronics

It has a 3.5mm jack on the side labeled:

DC.AC OUTPUT

I plugged in a mini - RCA cable to my stereo and it sounded just like a microphone but only in the left channel, there was no sound through the rt channel. I guess I need a mono 3.5mm plug, which I will get and make a cable. Actually I think I have a couple mono 3.5mm here which I was sent by accident, I'll have a look.

I guess I need a cable going from the SPL meter 3.5mm mono to a single RCA plug, and will measure the channels separately.

The sound card I have is the Chaintech AV-710, which is in the PC but hasn't been used for a long time. I use the Pico and don't ever use inputs to the PC.

I guess a 3.5mm mono to 3.5mm mono cable would be needed.




Bigshot, I'll play around with grounding when I get a chance but my system is normally "silent". I think it's just the 231 introducing noise, I will definitely try playing with grounding though.

Won't be touching it tonight sadly, tons of work to do.

Quote:
Originally Posted by stewart572 View Post
Steven

Copland makes a device that does that. I think Audio Connection in Sydney had one 2nd hand

Stewart

Thanks Stewart I couldn't find an EQ there but I found the Copland DRC-205 elsewhere, but all their gear looks very expensive and has more features than I need. I only need 2 channels etc.

I'm really thinking about the Rane DEQ60, if it sounds good. That's the kind of thing I need I think. It also has the option of 2 curves so I can have one for CD and one for vinyl, to "fix" the freq. response of the TT if needed.

Some great help so far, thanks all.
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post #34 of 37
2/13/08 at 2:44pm
Quote:
Originally Posted by bigshot View Post
I've had the same problem with auto EQ. It has to do with the difference between flat to the ears and flat to the mike. If you do a sweep and balance by ear, the bass will be just as full and even as the upper ranges.
Last year, I bought a TacT unit on Audiogon and it had some issues with completely losing the proper correction curve, which finally was verified out at TacT, so the seller took it back. But it did work properly at times, and that proved to me that what I'd read about a ruler-flat response via RTA was true.

It's clear in TacT's manual that the first of nine presets generated by the correction procedure is a "technically flat" response that will not sound anything at all like one expects. The rest of the presets invoke various house curves, some with even greater boost at the ends to evaluate at lower listening volumes. The software for that particular unit allows the user to create a custom curve for tuning.

I found one reference that suggested a roll off of 3 dB per octave above 2 kHz....that would put the measured response down 9 dB at 16 kHz, which seems a bit severe to me, based on the Fletcher-Munson or Robinson-Dadson curves at the 80 to 90 dB SPL range.
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post #35 of 37
2/20/08 at 3:36pm
This thread gives me a rare opportunity to agree with Bigshot.

Proper equalization can do a lot for a speaker system, unless you are in the rare situation of having speakers which already give a pretty flat response in their listening room. Generally this means big speakers and a largish room without few parallel walls and this is not that common although I have two such room in my house.

If you have a small squarish listening room you are going to have some nasty dips and humps in the lower frequencies that conventional tone controls cannot realy help and which realy need a some form of equalizer .

Still, my main speakers which measure +/- 5 db from 30 to 18,000 Hz without correction sound better when it is equalized to about +/- 2 dB.

I am not sure how some people are trying to do the measurements to do equalizing. My first experience was with scientific apparatus built by Bruel and Kjaer. It used a swept signal and a bank of 30 filters to get an accurate measurement of specific frequencies. It also cost more than my house of that date.

For some years I have used the older dBx 10/20 series of equalizers that use a pink noise generator and have a microphone input so you get sound pressure levels at one octave intervals. It is not as accurate as B & K but it gives fairly good results in its automatic mode. I then make a few adjustments to my ear, usually some reduction of the treble because many recordings already have a treble boost and can sound thin and dry, and a minor bass boost to give some oomph at low levels of listening.
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post #36 of 37
2/21/08 at 5:51am
Thread Starter 
Time for an update.

I gave the DBX 231 back yesterday. I had some success but not enough and am still looking.

I've been reading 5+ hours a night every night about the subject of EQ. It's almost as messy a field as cables! Loads of different opinions, info and equipment out there.

Some great reading is Audiocircle, Audioasylum and Prosound web, among many others.

I found the 231 noisy, and extremely noisy when any slides were moved from center. Not so noticeable with average loudspeakers but terrible through cans, although I wouldn't use the EQ with cans.

The main thing I had trouble with is working out what to adjust, and by how much. It would take forever by ear and I would never be 100% sure that it was right. What if there's a hole at 315Hz that I can't hear and don't know is there?

I figure the only way to go, at least to start, is measuring the response I have now, and moving the speakers/treating teh room to get as good as possible, then EQing the rest.

Trying to work out how to even get an accurate graph is hard.

All I did was as above, play 1/3rd octave test tones, record the reading on my meter and adjust for that, applying a correction curve I found on the net for the SPL meter. Not very accurate I'm sure.

I did get good results though once I had cut the biggest peaks at 32, 63 and 125 Hz, and others higher. I wasn't confident that it was good enough though.

I certainly see the value in EQ though, done right, and see it as a necessity for an accurate system. It just needs to be implemented really well, and it's harder than I thought it would be to figure out exactly what gear to get.

Even a Behringer mic and Edirol input device seems to have it's problems.

The ultimate seems to be a DEQX but that's several thousand.

I like the Rane gear, the RPM2 or something looks good, but then I still need someway to measure the signal I'm getting, and it doesn't correct for phase differences, and can't control crossover points and slopes.

I can borrow a DBX Drive rack PA, but would like to try the 260. Either will at least be able to generate and record a signal for measurement.

Will probably still try it as it's free but I am putting EQ on the back burner until I treat the room as I know it needs.

Later in the year I plan to build a bigger/better room anyway.
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post #37 of 37
2/21/08 at 3:05pm
Quote:
Originally Posted by stevenkelby View Post
The main thing I had trouble with is working out what to adjust, and by how much. It would take forever by ear and I would never be 100% sure that it was right. What if there's a hole at 315Hz that I can't hear and don't know is there?
It's good to go through the range and see what it sounds like with various frequencies boosted and cut. That's the learning curve. The advantage is, as you learn to hear frequencies and know the numbers to put to the various sounds, you'll get very good at sorting out what a 300Hz dip sounds like, and will quickly know how to fix it. You'll also be able to speak more precisely about sound here on the forums... Instead of a "veil", it will be a "slight drop in the 3-5kHz range".

See ya
Steve
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