# When wire DOES make a difference

100feet of cabling (+/- round trip per channel) just seems to be an abnormal length for speaker runs. (imo)

When I was confronted with such dilemma, a few years back, I resorted to 75feet of outdoor grade, 22AWG, copper. SFTP (8P8C) configured, Cat6a cable.

As I said, speaker cable @ 50' but 7 runs of it - only 1 direction I hope and it was 12 gauge wire, the same gauge that carries 110V in your walls in the US.

...only 1 direction I hope and it was 12 gauge wire...
How is that possible in a 2-wire conductor?

Hmm. According to wikipedia a 12 gauge wire has 0.0015 Ohm/ft.
• 50 ft of wire result in a resistance 50 x 0.0015 x 2 (two conductors) = 0.15 Ohm.
• 9 ft of wire result in a resistance 50 x 0.0015 x 2 (two conductors) = 0.027 Ohm.
• With a 4 ohm speaker we would see an SPL of 20 x log10(4/(4+0.027)) = -0.05 dB for the 9 ft cable, and 20 x log10(4/(4+0.15)) = -0.32 dB for the 50 ft cable, which results in a SPL difference of 0.27 dB. This is audible but far from WOW.
There's a factor besides a volume difference. Remember that unlike the signal interconnects, where inputs (as well as outputs) are actively buffered, the path from your amp to speakers and including the crossover is passive, so speaker resistance is part of the circuit consideration. And the impedance of the speakers aren't constant with frequency. If the output impedance of your amp is very low, as implied by a very high damping factor, the difference in resistance of the speaker wire can have an audible effect on frequency response, especially the low end.

I hit a noticeable change in sound decades ago when I bought a new system including so substantial Hitachi OFC speaker cabling, but had to go back to pick up the speaker cables the next day and used the low-gauge (18? Wasn't lower than 16) zip that came with the speakers. A surprising difference when I got the new speaker cables in, changing from a boomy low end to a tight one. (The amp is spec'd at "Damping factor.........>500 10 Hz-10kHz".)

Also, the resistance of even 12 gauge speaker wire can vary quite a bit:

When 12 Gauge Wire is Not 12 Gauge

As far as I know - there is a positive and negative terminal on my speakers and on my amps. So yes, 2 conducting wires, each 12 gauge, in one cable and it only goes from +/- amp to +/- on the speaker but no signal returns to the amp. You know, this stuff:

For the woofers I was using the much touted 12AWG Home Depot 3 wire extension chord. It was all the rage on audio forums 20 years ago. The wire for the midrange and tweeter drivers + 1 sub matched and I can't remember who I purchased from but I did note that the strands were soft and didn't strip well even with my good cutters.

I've put plugs back on the extension cords and cut 10' off the speaker wire runs but I'll break out my multimeter later, should be able to replicate Amir's test.

With very long cable runs of 12 AWG cable (1.03 mm rad.), skin depth also may start to become an issue in the high frequencies:

Unfortunately my multimeter is not up to the task it seems. I'm happy to let the dB mystery stay a mystery.

Massive change in spl from shortening speaker cable? Must be missing something here.

With very long cable runs of 12 AWG cable (1.03 mm rad.), skin depth also may start to become an issue in the high frequencies:
Well NO. Total loop inductance will have a much larger difference than 'skin effect' at high frequencies with most speaker cables.

As far as I know - there is a positive and negative terminal on my speakers and on my amps. So yes, 2 conducting wires, each 12 gauge, in one cable and it only goes from +/- amp to +/- on the speaker but no signal returns to the amp. You know, this stuff:
On terminal naming, several different equal labels.

Terminal A = Red = '+' = High = Plus = Send

Terminal B = Black = '-' =Low = Minus = Return

I'm sure that there are more.

an old friend always told me:

“remember that cables add nothing to the sound, they are necessary but passive "components". Then no! The cables do not “sound”!! at most like any passive component, they can remove, if not adequate in caliber, maintenance, connectors, length or type of cable.”

Probably having the possibility to measure everything properly, in terms of impedance and electrical capacities of the amplifier/cable/speakers, the best synergy could be found…

Your replacement probably allowed you to have better synergy between the components!

Longer cables do make better antennas though, so chances of interference can go up.

Massive change in spl from shortening speaker cable? Must be missing something here.

The reason I started the thread was I was glad to implement a balanced line level cable snake run as opposed to, I think we would all agree, a less than ideal speaker cable run that consisted of 7 wires going through unfavorable terrain. I didn't expect anything to change sound wise and yet somehow I gained some volume. I'm all about the science of why or I wouldn't be here for so many years....

For some who seem confused - this is an active DSP crossover, they are not active speakers.

I ran some measurements last night to try to figure this out. My tweeter channels were louder than before and I padded those back -5dB and discovered some other odd behaviors with the speakers that didn't show up before but this is hardly a comprehensive set of measurements. L/R playing together in 3 positions at LP 12' from baffles with a 90 degree mic cal on my Umik via REW.

Measured without subs and EQ to see what's happening.

This is more what I'm used to seeing. (with subs and EQ)

As I mentioned, I'm replacing the tweeters within the week. There is quite a roll off around 14kHz but I can only hear up to 16kHz. Something's up with my ribbons which have been in use from 3700-20kHz. I double checked specs and the Topping PA3 only has 19.5dB gain (vs 25dB single ended) with balanced TRS vs 25dB on the Hypex NC252MP so that is probably where the SPL increase came from.

The reason I started the thread was I was glad to implement a balanced line level cable snake run as opposed to, I think we would all agree, a less than ideal speaker cable run that consisted of 7 wires going through unfavorable terrain. I didn't expect anything to change sound wise and yet somehow I gained some volume. I'm all about the science of why or I wouldn't be here for so many years....

For some who seem confused - this is an active DSP crossover, they are not active speakers.

I ran some measurements last night to try to figure this out. My tweeter channels were louder than before and I padded those back -5dB and discovered some other odd behaviors with the speakers that didn't show up before but this is hardly a comprehensive set of measurements. L/R playing together in 3 positions at LP 12' from baffles with a 90 degree mic cal on my Umik via REW.

View attachment 369991
Measured without subs and EQ to see what's happening.

View attachment 369992
This is more what I'm used to seeing. (with subs and EQ)

As I mentioned, I'm replacing the tweeters within the week. There is quite a roll off around 14kHz but I can only hear up to 16kHz. Something's up with my ribbons which have been in use from 3700-20kHz. I double checked specs and the Topping PA3 only has 19.5dB gain (vs 25dB single ended) with balanced TRS vs 25dB on the Hypex NC252MP so that is probably where the SPL increase came from.
I'd read the thread, and thought maybe I did miss something....so you were using perhaps a lower voltage unbalanced connection to amp before the balanced connection? Did you make changes in the xover?

My main speakers are biwired with 2AWG THHN.

Because I could, from the junk box.

The nuts are 1/2 inch or 13mm for scale/

so you were using perhaps a lower voltage unbalanced connection to amp before the balanced connection? Did you make changes in the xover?

Yes, I was using a Topping PA5 for tweeters and switched to the Hypex because I have a 4ch Buckeye that I wasn't using 2ch on and wanted fewer boxes on the new shelf + the possibility of the Topping failure I've been lucky to dodge so far. When I glanced at the Topping data sheet I neglected to note that the PA5 only puts out 19.5dB of gain on balanced inputs vs the 25dB on the Hypex. No changes to the XO beyond padding down the tweeter channel.

edited to add: The connection was balanced before and after the change.

Yes, I was using a Topping PA5 for tweeters and switched to the Hypex because I have a 4ch Buckeye that I wasn't using 2ch on and wanted fewer boxes on the new shelf + the possibility of the Topping failure I've been lucky to dodge so far. When I glanced at the Topping data sheet I neglected to note that the PA5 only puts out 19.5dB of gain on balanced inputs vs the 25dB on the Hypex. No changes to the XO beyond padding down the tweeter channel.

edited to add: The connection was balanced before and after the change.
I was more thinking about the possible voltage increase with the balanced connection but different gain would be in the mix, too. Not particularly the wires, tho.

For over 30 years I have been running 50 feet of speaker wire because my amps, computer and DAC were all at my desk and speakers at the other end of a 30' room. Things got even worse when I switched to an active XO for my 3-way speakers 15 years ago and I had 7 pieces of 50' speaker wire for the 6 drivers + a sub on that end of the room. Even though I was running 12 gauge wire to the speakers I knew this was less than ideal. A couple years ago I scored a 50' 8ch XLR snake at a good price but had been putting off the chore of relocating the amps, ripping out cable and routing the beefy snake.

Well, over the weekend as a birthday present to myself I decided to dive into the project along with a phono cart upgrade. This is purely subjective because I have no way to ABX this obviously but WOW, quite a difference and I'm able to achieve a higher SPL than previously as well. Even though I used heavy speaker cable and it was routed in parallel it ran next to other AC cables and, until recently, some florescent fixtures. As of now, none of my speaker wires are longer than 9' - that 40' of added impedance wasn't helping anything that's for sure.

A shielded line level signal is nice and clean by any comparison. Not the fastest or easiest tweak I've ever done but a solid one for sure. Now to give the amps a little more airflow and some cable wrap is already in route to my door. Yup, big speakers, not pretty.

By reading carefully your introductory post, we have to understand that you change many things at one time, not cables only :

- fresh and shorter speaker cables ;
- fresh and longer modulation cables ;
- different cable routing in adverse electrical environment ;
- new phono cartridge.

There are many places were a clear cut audible differences can be explained by a mundane factor :

- your amplifiers were not stable enough driving very long run of speaker cable adding parasitic capacitance ;
- your previous modulation cables were not really balanced but unbalanced (who knows ?) ;
- until now, you heard mostly records with your new phono cartridge and have mostly heard the improved cartridge.
- etc...

By the way, the two graphs you just posted above have obviously been made at very different SPL levels and the traces are not displayed with the same smoothing. They are not comparable.

I think you changed to much things at a time to make proper observations.

I think you changed to much things at a time to make proper observations.

Since this is ASR I will explain once again and btw, I did indicate they were separate graphs. The phono cart has nothing to do with this.

The simple explanation is the new amp swapped in for the tweeters had additional gain causing a volume increase. If you are capable of doing so on your system try adding a high shelf filter at 3.5kHz with a 6dB boost and you will hear what I was hearing.

Yes, now I got it.

After your opening post telling us you just changed your cables and phono cartridge, and the statement in your second message (Post #6) that "Absolutely nothing else has changed" but cables, you tell in your third post that you also swapped amplifiers for your tweeters.

I suggest that you edit your opening post to put in a disclaimer about the fact the the "WOW" difference you initially perceived was in fact the supplemental gain you have mistakenly introduced in the high frequency ways of your system. That would avoid new readers such as myself the burden of wasting time to figure out what really happened.

D
Replies
0
Views
662
Deleted member 69358
D
Replies
1
Views
391
Replies
81
Views
4K
Replies
2
Views
403
Replies
13
Views
2K