Is it better to run long signals pre or post amplification? (1 Viewer)

[Joel Walker]

Speaking hypothetically, if one had the means to purchase independent amplification for each channel, or at least a seperate multi-channel amplifier for the rears, which of these approaches should yield the better final result? :

a) doing the bulk of a longer run (say 15-25+ feet) from the source & pre processor to the speakers with a low level signal, and positioning the amplification close to each speaker itself, or

b) amplifying close to the signal source, and doing the longer portion of the run with speaker cabling.

I suppose there is also option c), at least in principle, which would be superior to both (and increasingly costly, assuming technology even permits) -- send a post processed digital signal on something like optical fiber to the physical location of each speaker, where it is converted D/A on site and then powered.

any thoughts?

 

[Christopher Lyn]

I am no expert, but most, not all, people that run monoblocks have always said that it was better to keep the speaker cable as short as possible, thus, their monoblocks were placed right near the speaker. Therefore, one would have a longer interconnects than the speaker wires.

 

[Bob McElfresh]

Many high-end designers (Dunlavy for one) insist that speaker wires be less than 6 ft in length.

Running current/power through long runs of wire brings up issues that do not occur with line-level/un-amplified signals.


So the accepted rule seems to be: Long Interconnect, short speaker wire.

and increasingly costly, assuming technology even permits) -- send a post processed digital signal on something like optical fiber to the physical location of each speaker, where it is converted D/A on site and then powered.

In truth, this technology is dirt-cheap and has been around for years.

Meridian has one such system:

- Each driver has a separate D/A converter and mono-block amp. Yes, something like 50 watts for the tweeter and ... 80-100 for the mid-range. The woofer is separate.

- Each driver gets a separate twisted-pair feed from the central receiver. The wires have custom connectors, but appear to be simply twisted-pair computer network wires.

- The central 'receiver' is really a 'digital workstation'. Each driver in each speaker has separate level & equalization adjustments. A Microphone can be attached and placed in the central listening position. A "setup" sequence is run where the unit will perform all level-adjusting and equalization adjustments on a driver-by-driver basis. All settings are then modifiable by the user from the unit, but a Windows software package provides a better view/adjustment.

The Meridian 861 receiver alone costs about $12,000 (not including a few thousand for those custom wires.)

The reason why this system will fail is because it's a propritary system. You cannot mix other speakers/subwoofers/receivers with it. They DO offer a series of other "Digital Active" speakers in the $27,000 per pair price range as shown in this Cedia 2002 Expo report.

You are free to drool at the Meridian Web Site

PS: Paradigm had some "Active Speakers" - speakers with built-in mono-block amps, but they discontinued the line last year.

 

[Joel Walker]

Wow, thanks Christopher, and especially Bob for the good information.

We have a modest but quite enjoyable system these days. But, it's still fun to research what possibilities might exist for the next go round.

 

[Chu Gai]

is it three makes a charm? the theoretical answer is long interconnects and short speaker cables. In fact, theoretically, you just ought to weld the amp outputs to the speaker inputs. With the vast majority of preamps, the frequency response of the interconnect/preamp combo is phenomenally linear. For example, Fred Davis, who has published in the JAES has stated the following.

Subject:
Re: Bi Amp Interconnects
Date:
27 Apr 2000 17:26:19 GMT
From:
[email protected] (DALJHD)
Organization:
CompuServe (http://www.compuserve.com/)
Newsgroups:
rec.audio.high-end
References:
1

Why spend a lot of money on expensive, fancy-looking interconnects when those available from Radio Shack are electrically among the best available - regardless of cost.

Anyone that tells you that this is not true has not fully
investigated the facts.

Betcha!

John D.

Subject:
Re: Cables:Mass Delusional Psychosis?
Date:
21 Dec 1999 20:59:34 GMT
From:
[email protected] (DALJHD)
Organization:
CompuServe (http://www.compuserve.com/)
Newsgroups:
rec.audio.high-end
References:
1

As I and many others have stated many times, a complete set of the most accurate laboratory measurements do not confirm that any audible differences should exist between Radio Shack quality interconnect cables and the most expensive ones currently being marketed by the hi-end industry.

For interconnects, the two most important performance attributes are shielding and capacitance. Thus, even standard 95 Ohm (char. imp.) "RG" types provide a level of measured and audible performance that not even the most expensive cables can surpass.

A few of the more honest audiophile mag writers, like Howard
Ferstler, are now stating this truth (well known to competent engineers) on the INTERNET.

Best regards,

John D.

Now this doesn't mean that you have to buy RS, but it does give you some rather interesting insight into the area and it also keeps you firmly in control of your wallet. At least you have the knowledge that can guide your purchases.
When one has oodles of discretionary money it really doesn't matter does it? It doesn't matter if you drink tap water out of a limited edition Waterford Crystal bought at auction or whether your water is specially flown in from Antarctica.
The problem, as I see it, and I offer it as IMHO, is that the majority of us have a finite budget to work with. By going the monoblock route, spending accordingly on long interconnects, one is left with less money for speakers. And room issues aside, it's really the speakers that matter. So if by buying something like that H/K AVR8000 at onecall for under $1200 instead of say a preamp and a set of 5 or more monoblocks which may well cost you several thousand more, you can devote more monies to your speakers. Maybe even consider brands that you were putting out of reach.

Regretfully, the proponents of high end cables, whether they be manufacturers or salespeople or writers for magazines or even us end-users put up far too little to substantiate claims for audible differences. We hear things like 'improved soundstaging' (was it as much as moving your speakers apart an inch?), presence, detail, all the while without any valid, controlled, reproducible, comparisons. Nothing that is supervised. The terms that are used by the high-end crowd often are unknown. The distortions that are spoken of cause professors of metallurgy and electrical engineering to scratch their heads. But pass them off they do as white papers and as advertising and after a while its repeated by the reviewers and the general public. So can thousands or more people who say the same thing be wrong? Repeating an untruth over and over does not magically tranform it into a fundamental law. It really is all about making you feel good about your purchase. To my mind anyways, its as if one goes into a foul smelling room and after awhile, your olfactory senses just don't notice it anymore. In fact, late at night when you turn to one of those infomercials for the miracle diet, if you were to change those words around a bit, they just might start to sound like an informercial for somebody's wire.

There'll always be people who will counter the information with the standard lines.
My boy, your system just isn't resolving...it lacks the ability to exhibit detail and nuances.
My boy, don't you know it takes a lonnnnnnnnnnnnnng time to hear these differences?
Testing scientifically places enormous pressure upon the human psyche.
Why you're not trained to hear these differences. Trust me, they're there.
Even my wife, child, etc. heard them.
And the list of excuses goes on.

Allocate your monies wisely and purchase prudently.

 

[Wayne A. Pflughaupt]

For interconnects, the two most important performance attributes are shielding and capacitance. Thus, even standard 95 Ohm (char. imp.) "RG" types provide a level of measured and audible performance that not even the most expensive cables can surpass.

I once dissected some Radio Shack Gold cables, and the shielding was extremely poor. These particular cables were early 90s vintage – perhaps earlier. I haven’t cut up any recent cables, so I don’t know how they compare to the older ones.

Regards,
Wayne A. Pflughaupt

 

[Bob McElfresh]

Well, in my opinion they’ll have to drop the price a few hundred before I’ll consider it “dirt cheap.”

Ok, I was talking about 10/100 Megabit computer network cards that sell for $12 each on sale, Computer network cables for something like $0.008/ft, D/A converter chips under $1 in quantity (every cd player has one), and Mono-Channel/Monoblock amps that are actually a bit easier to design/build than stereo or multi-channel amps.

Meridian just upped the price because their marketing department tells them to target people with LOTS of disposable income. The technology is not exotic/expensive.

 

[Joel Walker]

Ok, I was talking about 10/100 Megabit computer network cards that sell for $12 each on sale, Computer network cables for something like $0.008/ft, D/A converter chips under $1 in quantity (every cd player has one), and Mono-Channel/Monoblock amps that are actually a bit easier to design/build than stereo or multi-channel amps.

This is interesting though. I had been in the mindset with the original comment of something like an individual component box coupled to each amp, which I imagined would multiply the dollars fairly quickly. Bob -- are you considering some "do it yourself" solution, or only saying that the circuitry is available cheaply to manufacturers? I don't suppose an ethernet card is much use without a pc? Also, I guess one could find 16 bit componentry much more readily/economically at this stage than 24.