I had some fun doing an acoustic experiment today. I made a pseudo anechoic chamber on my kitchen table out of FG acoustic panels piled into a box all around me. (Thanks to Carlman for loaning me the panels.) Interior volume was 32 cu feet, so definitely closed field situation, even with the hole in the bottom for the body to poke up through the table. I put cheap speakers inside, and stuck my head up through a hole made by removing a table leaf. It was very interesting. Detail retrieval even with the Infinity Entra 1 was awesome. Tape hiss otherwise unnoticeable became unbearable because it was was hiding details I would otherwise hear clearly. I started with my old Technics 40wpc stereo receiver and Nomad mp3 player, but that sounded very edgy and distorted with the details so well revealed, so I switched to wireless SB and Cary SLI-80, still with home depot stranded speaker wire. Big improvement in smoothness, but lows and highs still too loud. The mid range tone was superb but the tweeters really sounded forward and harsh. Bass at first was overwhelmingly loud, unlistenable. These are only 5" woofers, but they played down to 40Hz (and dead silent below that using test tones). 60-120Hz was way too loud (+20dB) due to the closed field acoustic, which was part of what I wanted to hear for myself after reading about it in Loudspeaker cookbook. Ported speakers just weren't intended for this situation and they suffered with screwy EQ, hi and lo.
The feeling of stuffy anechoic was weird at first, but after 30 minutes in there I was quite comfortable with it, it is really just the unfamiliar silence that "feels" stuffy. Once the ears adjust to the new lower noise floor, the stuffy feeling is gone. We hear noise all the time, and the brain adjusts to it. So when you take it away, brain in homeostasis wonders:
OHMYGOD the details!!!! I could hear the movement of piano foot pedals and the keyboard action, and the engineer coughing in the auditorium a long distance away. I could hear a lot more wood on Julia Fisher solo violin than on the big speakers. Lots of fuzz, rasp, wood, all that fart and puke sound effects that violins make live was revealed clear as day - on $150 speakers from Crutchfield. Granted, the Infinity CMMD mid drivers are superb, but still not really a high end speaker - or is it? Hmmm, in a well treated room, and the right situation, I think it is! Why have expensive speakers, to better deal with room anomolies. I know that my Legacys are designed around common room acoustic problems, compensation built right in. And it cost me too.
My wife Julie climbed in there too, she thought it sounded great. But on highly produced pop music, it is too revealing of punches, mixing flaws, EQ changes, even digital phase processing for Madonna's magic acoustic tricks. Laid bare for all to hear, clear as day, and very distracting from the musical message. The digital processing tricks like phase sounded like static, or 32kbps mp3 hash. On the big stereo it sounds fine, can't hear it at all. Quite an eye opener. Do I wanna hear crap like that, well, I don't know. On good stereo recordings, I do wanna hear it because it lets me feel the rear wall of the stage, or the woody rosin of a violin. But on normal pop records, no thanks, it is unintended production noise, not music. I don't think I want my expensive high end system (including the bad room acoustics) to be glossing over so much detail though, when a <1000 rig shows all (not including kitchen table and coconut oil pail.) haha
Bass was WAY too big at first, with speakers deep in the "front" corners, and with the semi closed field. I opened it up to the outside by removing the "rear wall" panel and pulled the speakers away from the front wall by about a foot, moved them close together and put my head into a 18" triangle. Wow. Clarity, intensity, details, tone. Not as stuffy. Almost as good as Carl's new Piega's that I heard yesterday!
So I learned something, I liked the reflection free sound, I like details, I like being able to hear deep into a recording, even the flaws. A little more ring would be more comfortable and probably more enjoyable, but I wouldn't want to give up too much of that detail. A larger space would feel better and allow drivers to gel better with some distance. Some EQ would even out the bass and tame the highs even with these speakers which normally sound fine in a real room. Maybe single full range drivers would be interesting. I like not hearing the refrigerator running while I'm listening to music. I will keep on with this acoustics exploration, I have some more ideas to try.
Thanks Bryan, for being so consistent in nudging me out of the big ring. I used to think I liked it, because when I deadened the front wall it contrasted too much with the rest of the super live room so it didn't sound good, even though it was solving specific imaging problems. When the whole "room" is controlled, it sounds awesome. The real acoustic is recorded on the CD, I don't need more from the room. There's no way I can deaden enough of my big room to tighten it up, Julie says forget it and my neighbor, our talented and free decorator, has chosen sides too. My mental gears are spinning. Next experiment will need lumber.
Pictures! (this is funny...)
Rich