Posted by Marty McCann on December 03, 2003 at 04:25:37:
In Reply to: Graphic EQ torture test posted by Bink on December 03, 2003 at 01:28:53:
Bink,
Glad you asked:
>>>
what other kinds of torture tests can you suggest?
<<<
Well there is always fader feel and accuracy of scale. Some that want to justify their purchases of the available bottom feeder products may not feel scale accuracy or slider feel as being important. But then, aren't we LABsters supposed to be the PRO's?
I say this because I recently was in a conversation regarding the lowest priced Equalizers, and some folks (that shall remain nameless) who export to foreign (but not necessarily what would be called 3rd World) markets, told me, "who cares about ISO centers and ANSI specs? What next, who cares about Constant "Q", Bandwidth, S/N, THD, CMRR, etc. ? Pleeeese give me a freakn' break. I care , and I know that you guys out there who want to be doing your sound jobs until they drag us kicking and screaming away from our consoles, care more than a little Sh*t.
Doesn't anyone but me remember Don Davis' stories about when Western Electric was broken up and the conglamerates that thought they could influence plubic opinion (read Hollywood Studios, Radio Networks, and Newspaper owners) and tried to to do it by controling the early audio industry? There are still forces in this world that want to get all the Gold they can. Don't let me have to tell ya'll the story of General Glutonius. Hopefully some of you know it. Oh my, I'm not becoming another Michael, am I?
But, if WE don't collectively bow up to the marketeers, and other prideless hucksters, who seem to be at least trying to drive our industries directional course, we can in short order take several leaps backwards into the audio technological Stone Age. Maybe we can save ourselves a lot of grief and just commission Sony to mass market 60's era WiFi tuned transistor radios with internal time delayed 4 Bit DSP's and ear bud's. ;>)
Guy's, IT IS ABOUT THE LIVE PERFORMANCE OF QUALITY LIVE MUSIC! Is it not?
My wife just came into the music room and told me to calm down! Was I cussin' and such? No. When I get upset while seated, I have this habit of randomly tapping both of my feet, and she heard it two rooms away.
So back to some suggestions; Some of the lesser expensive 1/3 Octave EQ's that otherwise are decent regarding the afore mentioned ANSI specs, may NOT necessarily be the very best tool when driving loooong lines with multiple paralled power amplifier inmputs at the end. I would suggest the typical old square wave test in a long balanced line of say 150 Feet, terminated with say a 2K Ohm load. My experience says that they will all exhibit ringggggginnnng, but it would be nice to know which ones eventually settle down. On a short feed to/and from Monitor World mixer via EQ Insert, most would be fine. But driving a long line may be different.
However as I hope I pointed out in the last post, the conventional filter bandwidths in both cut and boost mode, the depth and peak of the filter responses verses printed scale, how well they combine or NOT, full scale cut & boost ripple, etc., should reveal enough to prove that in the realm of EQ's, one indeeds gets what they pay for.
Another issue maybe to include some real world CMRR info. This is one where you could do the old trick of hooking up a electric fence charger to a switching mechanism to a good ole Autolite Spark Plug. Again a balanced cable run around the perimeter of the room should work for this test. I have noticed some signal processors in recent years fall below -60 dB in CMRR specs. If we have amplifiers that can do better than -100 dB S/N, why hook up a processor with less than at least -90 dB CMMR. Can we say transformer balanced inputs and outputs ?
Or has anyone ever experienced a cheap EQ or other processor in a highly RFI environment? What about just keying your cell phones or FRS two-way radio close to the unit DUT? Or how about at a University or other industrial environment that may have a Time Clock signal that is sent down the power lines? Surely I'm not the only one?
I forgot to mention earlier that one of the EQ's I tested, was so poor in it's ability to combine, that it actually shifted the notch of two adjacent cut filters to the extent, that a frequency previously removed as feedback, would all of a sudden rear it's ugly head a second time. Who would think that cutting 800 Hz an additional amount would cause 1 kHz to feedback again? I did mention this unit, but in a slightly different way.
I would also suggest that perhaps to put things in a perspective that reflects scale economies, that you consider catagories; such as EQ's under (U.S.) $300.00, then $300.00 to $500.00 or $600.00, then from there up to $1,000.00. Then maybe $1,000.00 to $2,000.00. As more than likely a $179.00 EQ would not hold up to one that was say $649.00. But then, who knows, there may actually be some real bargins, that the LAB community would be grateful to know about.
Perhaps some others can come up with even more suggestions? I am fresh out of ideas at the moment. And besides, I need to return to the fray started by the avowed Peavey Basher somewhere below! ;>)
After an 11 hour work day, I care enough to still get involved with our life's blood. But then for many of you I can't help but feel like I'm preaching to the Choir! Can I get an Amen?
Marty