Require Adjustable Delays For Speakers

[kelticwizard]

We are building a system which could use some delays for various loudspeakers. Two at least, preferably four.

The delays need to be adjustable between 1.7 and 17 milliseconds.

As echo effects and other effects which use delay circuits are built into relatively cheap boombox systems, I would hope to find a commerically produced unit for not a lot of money. Does anyone know one?

Failing that, we would not be averse to buidling a circuit, if it is simple, between the amp and preamp in the same general idea as Passive Line Level Xovers. Same idea, only a delay circuit instead of a filter circuit.

The last choice would be a delay circuit between the amp output and the loudspeakers themselves. We'll do it if we have to, but would prefer another solution, if there is one.

Since these would be for music, the circuit cannot affect frequency or phase response, at least not significantly.

Any help in finding a relatively inexpensive delay system to hook up, or building one ourselves, would be greatly appreciated.

[sreten]

http://www.sdiy.org/destrukto/vc-echo.html

/sreten.

[richie00boy]

Have a look at the Linkwitzlab site and his all pass filters for delay. You need to cascade several to get long delays like you want. You might find a better overall solution is to use a Behringer crossover unit as digital delays work much better.

[pinkmouse]

About ten years ago there were lots of multiband delays on the market for time-aligning PA systems, you might be able to pick one of these up S/H. Nowadays they all tend to be built into full system controllers with crossovers, like the DCX and Prodrive.

[kelticwizard]

Thank you all for the prompt answers.

I think Al's suggestion of second hand delay system for PA has the most immediate promise.

A few questions:

A) This will be used for the primary music system. From what I see, the delays seem to use digital chips. Do these things digitize the signal, delay it then put it back onto analog? If so, would you recommend this for a system that is your primary music system?

B) I am guessing that you mean Ebay when you say obtainable for near S/H price. Would there be any other method of obtaining one? How do musicians trade their equipment around? Builder is in Midwest, USA.

C) Can you give me some names of brands to look for? We would be coming into this cold, as far a pro gear is concerned.

[pinkmouse]

Indeed they do. I never noticed any obvious artifacts with good PA systems, (Turbosound Flashlight, Meyer MTL, Renkus Heinz), but home listening would be preferable. They should certainly sound better than an op-amp all-pass chain. I used Klark Teknik and BSS units. I liked the BSS because you could put in your delay times as milimetres and metres, rather than having to do any maths. As for getting hold of them, eBay is a possibility, but there are many dealers in Pro S/H kit around, you just need to do a little Googling.

[poobah]

Pink Mouse,

Sorry... OFF THREAD.

I couldn't help but notice you have a whole new look... is there something we should know???

[pinkmouse]

Originally posted by poobah
I couldn't help but notice you have a whole new look... is there something we should know???

Just working my way through the collection...

[poobah]

That's good... I thought you might have lost your significant other... you know... haircut, new clothes, all that.

I'll relax now.

[kelticwizard]

Having some trouble locating those multiband delay units. By multiband, I assumed it meant more than two channels.

The project requires four speakers to be delayed-with a different delay time for each unit. Well, three actually but four would be nice.

Checking out Ebay, what I mostly see are old delay units for two channels-and there is not separate delay for each channel.

That might be gotten around, since the builder is an electronic hobbyist, self taught. If these two channel delay units work by a DC voltage controlling the amount of delay, the problem must be that the unit has a system where each channel's delay unit gets the same voltage. A simple disconnection of the unit's voltage control, substituted by the insertion of a simple opamp whose voltage is controlled by the user for one or even both sides, should solve the problem. We might have to buy two of such units to get what we want, unless we locate one of those multiband units. Hard to find-or perhaps I don't know how to search for it.