A question for the audio guys of the forum.

Lately we have been doing these all night 30something "raves" (boy do I see some sights from these). You know, DJ's playing for 8 hours straight with me providing a monster PA, lights etc... I usually provide waaaaay more then they need so I can safely get to the godzilla volumes they want the music at. Anyhoo, I wanted to know if any of you have tips on avoiding low end turntable feedback in the subs. I can usually EQ it out (4-5db down at 40 and 60 Hz) but that usually takes away from the punch of the bass. Isolating the turntables from physical contact vibration does not work, so it must be transmitting through the air. I have 4 Meyer 650-p's and 4 Meyer MSL-4's per side for about 800 people. For those who don't know sound that would be like using a 500lm M6 to find your way to the bathroom at night!! (way too much) I thought of delaying the subs 30ms or so, have not tried that yet. When I get some free time at work, I'll have to set it up in the warehouse and try different things.

I don't usually work with turntables (or DJ's for that matter) so I don't have much experience dealing with this.

Give me 20 lavaliers and enough PA for 10,000 I'll do fine. Two turntables and a microphone is enough to drive me crazy!!

Also, do any of you know of a good bulletin board like this one dedicated to pro audio? For some reason I can't read newsgroups right now (hopefully I'll fix that soon)so it will have to be something I can read with a web browser. I'm looking for a group that is as knoledgeable and professional as this one (if that is possible).

you were on the right track, isolation is the key...good techniques turntables are a must and a good coffin...some raves they suspend the coffins from the ceiling using something like stiff bungee cord, it's more of a temporary thing...the last club install i did i had them put these big round steal pipes a foot accross mounted to the concrete floor (the dj booths were up high) then filled them with sand and then put small platforms on top just big enough for one turntable and made sure it wasn't touching anything all the way up and around...it worked out fairly well, only one of them neded a little more attention later...

watch out for hollow surfaces like built up sealed wooden stages and such...they're big bass traps, basically the surface acts like a drum head...

as a jury-rigg fix you can put a bunch of foam under the tables, this has helped me out some in the past...make sure they aren't touching anything as well, like the cases that they are in or the sides of the coffin...there are shock absorbers in the feet (in good tables at least) that get nullified if they're touching anywhere else...

We have techniques 1200 turntables. I actually had people stand and hold the turntables by the feet to see if isolation was the key and that helped a bit. The DJ's we were working with had this contraption setup: cinder blocks holding a heavy door for a table, raquet balls cut open holding a cement plate then the turntables on the cement plate.

The place we hold this event has moveable floors and is hollow underneath. This is probably the biggest obstical. If isolating it from physical contact is the key then I'll have to experiment with that.

Oh I forgot to add, this is a temporary location. It is completely setup and torn down every time. The configuration is like a concert with the DJ stage in the middle of the stacks. That's most of the problem, but that is the only place to put the speakers and DJ.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Tree:
For some reason I can't read newsgroups right now (hopefully I'll fix that soon)so it will have to be something I can read with a web browser.<HR></BLOCKQUOTE>

Go to this site to read newsgroups:
http://groups.google.com/

It used to be www.deja.com

Uhhm, Turntables? Like for LPs? I live under a rock. And, can't imagine such a preference over digital. How are turntables an advantage? With all this 256k mp3 and 1.41Mb audio, I mean...Why?

It's not about clarity and digital convenience. They seem to prefer the feel of LP's. I think it's half what LP's actually have to offer and half the "ooooooh that's soooo retro and cooool" way of thinking. I can tell the difference in the sound when they play CD's in the middle of their set. It's hard to explain, but to some of these DJ's LP's are the only way to go.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by BuddTX:
Go to this site to read newsgroups:
http://groups.google.com/

It used to be www.deja.com<HR></BLOCKQUOTE>

Awesome, I forgot about Deja. Thanks

Looking up queries I found (among many answers) using hot water bottles half filled under whatever the turntables are sitting on seems to do the trick. There seems to be as many fixes as there are clubs!!

Isolation is hard enough in a permanent setting!

I know one fellow who used Glass Bricks, Cork, Marble and Steel (This to create a lot of impedance mismatches so the sound would be reflected) and nothing helped!

I'm not a raver, but the few I've been to, I'm not looking at the sound equipement, or the lights... I'm looking at the women.

PS: My Bloody Valentine, "Loveless" track 12, "Soon" always get's 'em dancing, and no one knows what song it is...

Download it from Morpheus (Soon-My Bloody Valentine) or Audiogalaxy to see what I mean.

I know what you mean about the women. Boy have I seen some things. I'd never go to these things if I was not working them. During the shows it's not much work, mostly me going through all the rooms making sure they don't blow up any of my speakers. Then slowly turning up the highs throughout the night so the sound compressed ears of the guys who hired us will stop telling me to turn it up. I measured 115db with 119db peaks on the dance floor this last show about the middle of the night, it got louder from there!! I was wearing my custom fitted 35db earplugs and it was still too loud for me. The best part is I can go anywhere I want like VIP rooms. That's where it gets the craziest.

Actually I am looking to buy a LP or two to test different methods of feedback prevention. Also, to burn a few CD's with current favorites. I don't listen to the music they play therefore I have no idea what to get. I'll look up Soon-My Bloody Valentine on Kazaa.

Nice homepage...

BTW: Anything by "CURVE" is very good, especially the early stuff. Some people say the band "GARBAGE" stole their sound from them. Very unique, and has that "where have I heard this great song before"

Espically the songs, Clipped, Frozen, and Fait Acompli


PS: Re: The Women: Ya. But it's contractual. I mean, a lot feel they have to do it, to get attention.

Makes the night go faster, tho... heh heh.

Oh. Ya. Flashlights... The new LED ones are neat, huh?

Tree, if the floor is hallow, try putting the subs up on something. I would start with maybe 1 inch insulating foam (pink or white stuff). You could stack them on another sub and not use the bottom one, or maybe just try shutting off the bottom sub and see if that helps. Otherwise I would try shock isolating the turntables (you already did that), then getting the subs just off the floor, then try delaying the sub feed as you mentioned. Moving the turntables further from the subs probably isn't an option, but that would fix it also.

Isolating the subs from the floor is a good idea. It will have to be something sturdy though. All the speakers are stacked so that's almost a ton under the subs . Maybe some kind of thick rubber mat. I tried flying the MSL's last time and I lost too much spl with them in the air. I like to have all the speakers right there in the dancers faces so I don't have to turn them up to dangerous (for the speakers) levels.

As for LED's I do see a lot of those blinking "ravin" LEDs although I never seem to get close enough to see exactly what brand they are.

With the women, these parties are themed. So the outfits are usually pretty extreme. This last one was Barbarella, before that was White Trash, and before that was Skin.

My homepage is just something I threw together so my friends would quit asking what to do on the net. It's basically just a part of my Favorites folder dressed up as a web page. I have bigger plans for it and www.onetontomato.net reserved I just have to spend some time on it and see where I want to go with it.

BTW don't click on onetontomato.net yet. It is on Dotster and until I put a page up there will be a bunch of pop ups.