Hi mb
Most definitely! Hugh, do you have any thoughts on that? I'm not really sure what's involved with things in the time/phase domains when EQing in the digital realm, either.
Do you have any tips on how best to dial things in with the DEQ? And what do you need for cables?
Dayne
Hello All,
an interesting discussion brewing here.
Warning: some opinion ahead!
I should start by saying that a number of new HT and car audio developments make extensive use of EQ to try and achieve certain effects. Used judiciously these can be decent solutions to bad room problems.
These digital units usually perform filtering using one of two methods: IIR or FIR. BOTH methods introduce time domain anomalies into the signal, in particular ringing and degraded transients. Both types affect the phase of the singal although FIR filters can be made linear phase by using symmetric filter structures and can be extremely transparent if enough DSP is thrown at them. IIR filters are more efficient computationally, so many graphic EQ systems use these, although some of the better ones use FIR - especially now that DSP is becoming cheaper.
The Klark Technic systems for instance, but if I had $11K to spend I'd spend it on the room.
I used to do a bit a live sound stuff where this kind of EQ is vital. However, in the home you need to ask yourself if radical EQ to flatten out the room is worth the sonic degradation in other domains (impulse, phase etc). High frequency room problems can often be remedied with some cheap, and high SAF wall hangings and concealed foam, but I would have to concur that short of rebuilding the room from scratch, taming bass modes is really only feasible with EQ, and great results can be got this way which will often outweigh the sonic penalty of an EQ.
A good way to get the best of both worlds is to use a parametric EQ and attack only the problem frequencies, leaving the small dips and bumps elsewhere alone. Parametric EQs are often linear phase FIR so less harm is done. You'll need to check that the filters are capable of fairly high Q. Of the order 50 or more to get anything like a sharp notch. Of course a lot of these digital eqs do this no problem. I have a DEQ with a Q of 100.
If starting from scratch wth room taming it is worth downloading one of the many free realtime analyser packages from the web and buying a cheap measurement mic from a local electronics or audio shop and measuring your room. This way you'll get a feel for what is going on. A flat room isn't necesarily needed for great sound. Sure you want it *pretty* flat, but having a smooth and short RT60 (time for a test pulse to drop by 60dB) at all frequencies (so smooth REVERB) is much better for sound quality (vis a vis bass booming which is a kind of reverb I suppose).
One final comment, I think JohnR has a point. I don't know the specs of the 8024 or the DEQ 2496 (but I'll chase them up). Many units do use sample rate convertors and this came up in the AES circles about 2 months ago. jury is still out, but general vibe is that multiple sample rate conversion steps introduce some real nastyness, which can be acceptale with "good" systems and downright vile with "bad" ones.
My 2c. Grab a book on acoustics. Measure the room first. EQ the bass modes (unless you hav dipole speakers!) treat the treble with wall hangings. This approach has the biggest impact on quality, for the least cash with the least deleterous impact on sound.
Cheers,
T.
