Cheap PEQ

celef

Member
2012-11-26 7:40 pm
I need to tame some bass frequencies in my room and want to use an peq but not a dsp based one, i need 2 channels and 3 bands (is that what they are called?), any suggestions?

I could also use a graphic equalizer but they are said to introduce a lot of phase errors, i do not know about that, do you have any thoughts?
 

celef

Member
2012-11-26 7:40 pm
wow, that is great, because i am not allergic to phase shifts that i am aware of

and there is a lot of graphic eqs choose from, and many very cheap too, but the operating level range seems a bit limited, is it good to set all bands to max and decrease problem freqs accordingly?
 

celef

Member
2012-11-26 7:40 pm
It seems most (all?) geq has a switch for +-6db or +-12db range for each band, 12db would be sufficient for my needs

I thought that each band in a geq altered the phase response even when set to 0db, if that is not the case then geq might be a very useful tool
 
I was going to suggest an Ashly Audio SC-66 vintage stereo parametric equalizer, seems they have a following and in some places are now selling for more than the when new dealer price!

Ashly made more parametric equalizers than anyone else. One of their secrets was they bought the required potentiometers in bulk and then changed the front panel silkscreen to match the actual tuning results.

If you do acquire an Ashly unit you may want to re-chip it with something more up to date. That would require decent test equipment to take any oscillations that might result.

Audio Arts also made noteworthy parametrics, but far fewer.

DBX were never in the same league with those two, in terms of sound quality. Mostly because they used cheaper potentiometers!

Of course you could buy a classic unit, try it out and resell it if you wanted to play and minimize the cost of the experiment.

BTY the earlier Ashly gear had blue faceplates. More recent are the black ones.
 
Yes i know, but if peq do just as much harm as geq then i thought a geq could be cheap solution. I really would like to see a freq response graph for one band at a min/max setting


Room modes can be cured (on one place only) with IIR filters, iow analogue filters.



You can add IIR filters.


The final result at your ears is the addition of many IIR filters in the chain, electrical, mechanical and acoustic filters: the eq that the mic has naturally, the eq that was added by the sound engineers, the eq from the mastering engineer, the eq from your speakers and the eq from your room etc. All of these are IIR filters and thus can be changed with IIR filters. If you do this correctly, you'll get a neutral sound at your ears.


Ashly is highly recommended.
 
They surely weren't audiophile quality, but Moog used to (late 1970's) make a wide-range 3-band parametric. I ran 3 of them with excellent effect for quite some time. You'll need to tune up your ears for the extra work, though -- the front panel silkscreen is only 'in the neighborhood'.

There might be a few floating around cheap that their owners have gotten good and sick of -- a buddie owned one, too, and it developed an 8 dB intermittent that confounded at least one tech (me!;)). Was finally traced to a weak DIP 8 socket, and as far as I know it still works just fine.

Ashley is still much better, but if you found one of the Moogs and replaced those sockets, you could have a lot of control range to play with, for probably not much money. Might help you sort out what you really want / don't find objectionable.

Regards
 

celef

Member
2012-11-26 7:40 pm
that is good to know, thank you very much!

i can not help feeling that using eq is a little bit like cheating, i think it would be better to really treat the low freq room boom i got then masking it with eq, but eq just seems like a sweet and fast solution. when i move closer to the middle of the room, getting out of the boomy area, the sound is so sweet and linear, i hope a eq can bring me the same sensation
 

AllenB

Moderator
Paid Member
2008-10-18 11:31 am
Sometimes EQ is appropriate and sometimes it isn't. When it is right though, everything is good, including phase. When it is not appropriate you can tell it isn't satisfying. (sometimes there is more than one thing going on at once however and then you may not tell much by listening.)
 
The 'little bit like cheating' notion is hard for me to accept. Maybe I've just been a blissfully prolific cheater for too long.;)

As for the room boom, surely fixing the room would be ideal. But typical non-performance rooms often have very difficult issues that can't be economically fixed even with the help of modern analysis software.

Also, EQ doesn't really 'mask', which would imply adding something to hide something else. Its really just deciding to deliberately under-stimulate the objectionable room modes.

The fact that you have a sweet-sounding area is a great sign -- and probably one that an acoustic remedy would be well suited to. But a parametric could also give satisfying results, as could the IIR/FIR (sorry I don't remember which) digital. And you'll surely have more fun than an acoustic solution that would have to be thoroughly studied, measured, planned, and carefully implemented, cost nearly as much or more, be vastly less flexible, and risk a higher spousal objection coefficient.

Cheers