[sdiy] "Time Winding" in Audio Cables ???

[Magnus Danielson]

From: Richard Wentk <richard at skydancer.com>
Subject: Re: [sdiy] "Time Winding" in Audio Cables ???
Date: Mon, 11 Jul 2005 19:09:32 +0100
Message-ID: <5.1.0.14.2.20050711190443.04336da8 at mail.skydancer.com>

> At 16:47 11/07/2005, Magnus Danielson wrote:
> >Exactly. Passive filters? Whoooo, do I need to say more???? Toss your big amp
> >aside, the passive filter is burning your power away and your control of the
> >elements is not being changed greatly by the amp.
> 
> Up to a point. A lot of amps don't have the drive need to handle a 
> filter/speaker combination without splattering the sound, so something 
> beefy will be more likely to do a good job of it than something cheap.

You loose alot of dynamics that way. You need larger amplitude for the same
effect etc. If you would run two-way or three-way active crossover with
suitable amplifiers you would have less total amplifier effect for the same
overall soundlevel than a single amp with passive filter. There are many
benefits for going this path, at the cost of spending money on several amps
rather than a single amp.

> But it's interesting that there are so few active designs around, with - 
> say - the speaker/filter in a feedback loop to try to minimise distortions.

????

An active filter sits before the amp, dealing with signal-level signals.

> I think Philips tried this at the consumer end, but it wasn't a success. 
> Potentially some kind of accurate feedback could go a long way to 
> cancelling out non-linearities. But it would be a pig of a thing to design 
> and implement, and probably insanely expensive as an R&D project.

Horror!

> So-called active speakers don't usually do anything like this. They just 
> eliminate the speaker cable by putting the amp and speaker next to each 
> other, and (usually) making sure the amp section is two independent 
> monoblocs, which always helps anyway.

Actually, I've designed two-way and three-way systems with ampracks well
separated from the speakers. Cables included! ;O)

It works, it makes sense and it plays loud AND clear.

Cheers,
Magnus