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O.k. I'm looking for a little help here for theose of you who may be more fluent in electrical engineering than I am.
I have a dilemma.
I have recently left the pro audio field to a part time obsession, and obtained employment working for a consumer audio/video store. I am working as a salesperson, and so far I'm doing quite well. My problem is this: I have people trying to convince me to use $80 cables to connect my subwoofer. They want me to buy BOSE speakers, and subwoofers that are now "omnidirectional" due to advances in technology. :roll:

Here's my question. First of all does anyone have some strong math to support the benefits of 15picofarad/foot cable over 50pF for a subwoofer? 10k impedance 300mv line level?
I have had two employees tell me of the wonders that "good" cable has done for their subs. I tried the same experiment tonite and it made no difference to me or four other people. Which one of us is crazy?

How about cable in general on an under ten foot run? I know in the studio you don't have to get too crazy for such a short run, but we run lower impedance connections and a +4dbv signal.

The very different way that consumer audio interacts has got me second guessing what practical experience has taught me.
I would like to evangelize my crew and help them to become enlightened in the ways of pure sound, but I lack a good argument.
Someone, please help.

Steve.

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Comments

John Stafford Sun, 07/24/2005 - 01:39

I hope there are no BOSE fans here, but I think they make crap. Maybe not quite as bad and Bang & Olufsen...

The subwoofer thing is BS. Bass that deep can't be localised by humans.

As far as the cables go, if you can't hear a difference, there isn't one. As you have been in the pro-audio field, your ear will most likely be more finely tuned than theirs anyway.

John

hociman Sun, 07/24/2005 - 06:49

vinniesrs wrote: First of all does anyone have some strong math to support the benefits of 15picofarad/foot cable over 50pF for a subwoofer? 10k impedance 300mv line level?

Here's some of a chart that was in the November 2004 issue of ProAV magazine:

Source Impedance 15pf/ft 50pf/ft
150 ohms 1,873ft 541ft
600 ohms 451ft 135ft
1k ohm 271ft 81ft
10k ohms 27ft 8ft

The distances above are how far you can go before you are down 1dB with a 20kHz signal. High frequency loss occurs before low frequency loss, so if that is part of their argument (distance), here's proof that its moot.

More importantly though, capacitance affects high frequencies, not low ones. If they are basing the improvement solely on the pf/ft rating, they are full of it. Or are they? Capacitance affects high frequencies, but resistance affects all frequencies equally. To have minimal resistance loss, you need a low gauge wire. So if you can get a lower capacitance by using a lower gauge (thicker) wire, then they may be hearing a difference, but its not attributable to the lower pf/ft rating. It's attributable to the lower resistance of a lower gauge (thicker) wire.

The bottom line is if you hear a difference. Just because you don't doesn't mean your deaf. In fact, it may mean that they are brainwashed. :wink:

moonbaby Sun, 07/24/2005 - 07:06

Mr. Stafford, I think I'm in love! I used to sell "pro audio" and high-end hi-fi. I learned very quickly that Bose were built with the crappiest drivers Eminence could make,and their efficiency and response was deplorable. Unfortunately, I live in a household where the woman-I-love :D has a lust for Bose. The 401, the 601,etc., all around the damned house! They are BS. Always have been. They are designed to appeal to the occasional music lover's feelings and emotions (the "gestalt" factor?). I fight back with the "male" version...a pair of Klipsch La Scallas (probably the most "hyped-sounding" speaker in history!)...
As to the subwoofer, unfortunately they are by nature, omni directional. I can't see that changing in our lifetime...something to do with physics...
Like I said, I used to sell gear. Cables are some of the biggest profit-generators in the biz. I'd be lucky to make 15% off the gear, but 100% on the cables to hook it all up. A lot is hype, total BS.
Marketing pro's run this biz a bit too much,IMHO. PEACE

KurtFoster Sun, 07/24/2005 - 13:21

Please sell me your La Scallas .... I want them for my PA!

Bose speakers are ok .... home stereo stuff ... I would never try to use them for recording. I had a pair of some Mitchell speakers I used for PA work, that were copies of the 801's ... in a fiberglass cab. They kicked ass to a certian point and then they were usless. Sounded wonderful in small rooms, no good (except as mons) in larger rooms. They were cool and easy to fly from the cielings in smaller nightclubs. Took a ton of powere though to get loud.

Every sevice tech I ever met or had in my studio doing repair or installation work has told me that speaker wire doesn't get any better than 12 or 10 gauge copper wire. I agree. I have tried Monster wire and heard no difference. Not like the difference a good mic pre can make.

IMO. high end wire is aimed at the "audiophile" market ... and some of those people just need to spend money.

JoeH Sun, 07/24/2005 - 14:34

We could make up funny names all day for products we don't personally like.

I'm ok with Bose's for certain things, nothing crictial, certainly. I've done hundreds of corporate AV gigs with a contractor who's got several Bose 801 and 802 systems, along with subs. He's still working today, and his clients love his rigs for big meetings and events. They're fine for what they are, when set up properly. They seem better for sound-all-around instead of direct sound; their stereo imaging isn't anything to write home over either.

But far too many people don't even know about the Bose EQ unit needed inline, ahead of the amps. I've seen way too many "Smiley face" EQ curves done in place of the factory-spec'd EQ modules. Not the same thing, and it's no wonder so many people hate their sound. They DO sound horrible when run that way.

But back to subwoofer wire: It's kind've moot if you're using a powered subwoofer. (That's all I've ever used in my systems here, including my mixing/mastering suite.) If you are using a separate amp, it's just best to keep the run short and use the smallest gauge you can find, with good, solid connectors. (10 or 12 guage should do.)

Even hi end people like Lipinski Audio (Speaker, amp & preamp manufacturers) doesn't suggest you worry about anything longer than 5 or 6 feet of good, solid speaker wire. They do NOT put amps inside of speaker boxes; all of their designs are passive. They recommend 12 or 10 gauge wire to go from amp to speaker, as short as you can make it. (If it's good enough for them, it's probably good enough for the rest of us.)

Enjoy your bass for what it is; with good wire or an amp inside the box, chances are, it's fine.

moonbaby Sun, 07/24/2005 - 16:34

Kurt! I used to use a set of 4 LaScallas powered by a pair of Crown DC-300A's for a "Chicago/ BST"-type of big-band r'n'r sound!
I bought the current pair out of a local classified ad paper. $200.00!! All the components work, but I need to find horn diaphragms. These are waxed paper-looking....I am powering this pair with a a pair of McIntosh M60 tube amps...a match made in heaven!

Kev Sun, 07/24/2005 - 17:15

moonbaby wrote: All the components work, but I need to find horn diaphragms. These are waxed paper-looking....

could be phenolic
look through the old EV stuff and they might have the unit
The tweeter was a RE-badged EV and I think the Mid drive was too ... but the flare was ALL Klipsch

Now that Klipsch is marketing their classic range again .. I'm sure they have spares

vinniesrs Mon, 07/25/2005 - 18:09

Thanks for the feedback guys!
The subwoofer thing was a joke. I have had my fair share of experience with arrays and I'm keenly aware of how soundwaves behave; I'm just waiting for the rep for this company to try and disprove the laws of physics at our next training. :lol:
As for bose???
I wouldn't use a cube speaker for a paperweight in a hurricaine if I was dying and the paper was my last will and testament! :D

Sometimes when you have 600 people all telling you you're wrong it gets tough to stick to your guns.
My boss told me that several major studios were wired with monster cable. I told him that monster cable is fine for that job, but no one in their right mind would pay that much for cable in a studio. I said that if this was the case it was a freebie deal.
The whole argument started when I saw a 3 foot rca patch cord for $60. I said I can't sell this to someone unless they specifically ask for it. I won't recomend that someone pay $60 when they could have the same performance for $10 . I think people appreciate knowledgeable sales staff who are honest, and in the same situation would gladly put the hundreds they save in cables to better use in their gear budget. On the other hand Video cables DO make a difference, but that's 1.000.000hz not 20.000hz?
Thanks for the chart hociman! That is exactly the information I needed, or at least some of it.

If someone knows roughly how many microhenrys' of induction one could see in these cables related to a signal level of 300mv this could be helpful too.
Also what about signal delay by frequency in conjunction with varied capacitance?
I know these things exist but I don't have the skills to fugure it out for my self.
Thanks again.
STeve.

dpd Mon, 07/25/2005 - 20:34

Generally, I'd opt for lower capacitance cables - especially if you plan to use long runs. But not for the fact that they will be flatter at high frequencies. Too high a capacitive load can cause certain power amplifiers to go unstable and oscillate at ultrasonic frequencies - this can lead to premature amplifier failure and/or distortion products folding back into the audible band.

Anyone here remember the Polk Audio Cobra Speaker Cables?

moonbaby Tue, 07/26/2005 - 04:29

Polk Audio Cobras......vaguely!
Yes, the LaScallas have phenolic diaphragms...the tweet IS an E-V, but the mids are ...ATLAS ( I believe that Klipsch went to E-Vs later for this driver). There is a speaker repair shop here that can provide me with aftermarket parts for these. No one commented on the amps :( ...

moonbaby Tue, 07/26/2005 - 14:22

I did not know that Klipsch was bringing the LaScallas back. I would think that they would be using components from Eminence.
They are basically the only real American manufacturer of actual drivers for stuff like that around these days. I think that E-V has gone on to other markets, and JBL, well....
Just don't try to MIX on those babies!

anonymous Wed, 07/27/2005 - 11:06

I used to live with a guy obsessed with Bose. His speakers came in, he stayed excited about them (and still is), and we had a big fight because I pointed out that my '70's Kenwood amp --> early '80's Sharp speakers had a much better sound, and the RTA backed it up.

Anyway... enough about the rant on Bose.... I can do the same about Dell.... get a reseller's permit or sales tax license or whatever it is in your state and you'll see that you can build a Dell XPS for <$500....

moonbaby Wed, 07/27/2005 - 14:10

You could build the PC alright, but then you'd have to: ship it to the wrong address, include the wrong (and totally useless) software,
ship the right printer with the wrong cartridge, include a "free" printer cable and then "forget" to pack it, and...
INVADE YOUR CUSTOMERS" WORKSPACE WITH TOTALLY USELESS POP-UP SALES ADS FOR CHEEZEY HOME ELECTRONICS!!!