Thump

[rghinton]

I am using an Audio Control, Model 3, Phase Coupled Activator with my 2 Altec 620's, 3 Altec 417's and 4 Altec 8182 bass enclosures with 3182 woofers. This accessory recreates and adds bass that was removed in the recording process. I really like the additional kick that my system now has. If I turn this unit on or off while the power amplifiers are turned on, there is a real loud thump through my speakers. I do not want to have to turn this accessory on before I turn the amplifiers on. Sometimes I forget. Does anyone have a schematic of what I need to modify in this accessory or any accessory to eliminate the turn-on, turn-off thump. Is there something I need to add to the power supply or the on-off switch. I know that some accessories do not have this problem. Schematics are not available for most equipment now days. Thank you. Reed

[Steve Mac]

Hi Reed,
Hey I'm confused.
First you are not restoring anything lost in the recording process. Second you are hooking up a sub-harmonic generator to some very beautiful and very large bass enclosures. I gotta ask a basic question... why?

[rghinton]

Hello Steve,
I just finished taking a class in recording engineering. One of the things that we were taught was to equalize the recording to fit the playback equipment such as small CD Players, the average car radio, average TV's and small radios. We were told to reduce some of the lower frequency response to avoid overloading many of the average reproducers. I have the restoration control of the PCA turned about 1/20th of the way up and am adding very little recreated sound but the added sound adds a lot to the movie experience. I believe that the system that I am using is one of the few systems that can handle a little boost. I am not debating the pros or cons of the accessory. I just don't want to blow an amp or speaker because I did not turn my system on in the proper order. I really dislike the booming that I hear out of some car audio systems. The additional low end that I am adding is more of a breath than a boom. The 3182's can reproduce what ever I ask of them. I just want to know how to modify the unit so I can turn my system on in any order. Thanks for your comment. It re-enforces my belief that there is no place for booming bass while listening to music or a movie.
Reed

[Old Guy]

It's impossible to "recreate" sound. It's only possible to synthesize it.

Once it's gone it's gone. Yes yo roll off bass during recording- but that machine doesn't put it back. It makes different sounds to take the place of what was there.
No matter how you slice it, it's artificial. if you like it, fine. but it aint real.

[rghinton]

Hi Old Guy,
I learned by taking the recording engineering class that there isn't much of anything real on the final product of a CD. There is remixing, moving instruments from left to right or the other way around, compression, over dubbing. I really prefer setting up the mikes and instruments in their correct position, working on the room acoustics instead of equalizing, not compressing the sound. I want the music to sound real. With my experience in the recording studio, I feel that by synthesizing the low end and adding ever so slight amount of this signal to whatever I am playing that I am hearing something that sounds more realistic to me. This thread has deviated from my original question but there is a lot here that is worth thinking about. Thanks for the comments.
Reed

[Old Guy]

As far as removing the thum, not a lot you can do.

How it's done with power amps is to delay hooking up the outputs until the thump has passed.

I would suggest wiring the unit so it's always on. Other than that, you'd have to cobble up a bunch of relays.

[bfish]

Hi, Reed,

The ideal setup for power-up/down operation is a Furman or equiv. power sequencer w/remote. Not cheap.

Us po' boys just hafta remember to power up with the signal flow, and power down the amps first. Unless you've got a switched outlet going to waste, that is.

I use an old dbx sub/synth for effects on electric piano, where it gives me exactly one more octave. I've never tried it on playback, but can understand an argument for its' use there. Yes, it's synthetic, but considering the specific octaves they operate in (3rd octave, 80-160Hz tones are copied to the 2nd octave, 40-80Hz), they're very effective in substituting a missing or compressed fundamental. You might call it an effective effect.

[Old Guy]

The synth can be a pleasing effect. I think, after re-reading my post, it sounded like I was being critical of Reed- that wasn't my intention. I was being critical of the "re-create" labeling on the controls. nothing but a sales gimmick.

It's a synthesizer. The manufacturer should be honest.

[Old Guy]

Good point. Effects are best used sparingly- I remember one night playing with a guitarist who had just bought a wah pedal- every song that nite had wah on tne guitar whether it was appropriate or not.

The sonic maximizer is another toy- it can make a bad system sound a little better- but generally makes a good system worse.

[Steve Mac]

I would think some restorative EQ, if needed, would be a more straightforward solution. I've taken some graduate level courses in recording and yes, being able to play the music thru garbage is a definite consideration. That sounded a bit jaded...sorry didn't mean it like that. Still, having used sonic maximizers and aural exciters, ...I've noticed that used sparingly to some recordings they do tend to make things sound good or add a sparkle.