• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Effect of Speaker Cable Length Mismatch

radix

Major Contributor
Joined
Aug 1, 2021
Messages
1,370
Likes
1,300
Wouldn't doing room correction (dirac, audyssey, etc.) make any differences in speaker cable length irrelevant? I'd also think that differences in room placement of each speaker would swamp the effects of small cable distance imbalance. Is that wrong?
 

restorer-john

Grand Contributor
Joined
Mar 1, 2018
Messages
12,584
Likes
38,283
Location
Gold Coast, Queensland, Australia
I've tried with another set of speakers and cables and found out that the problem is on the amp, since the behavior is the same on both sets, which are very different. It requires the volume to reach some threshold to start working properly. Before this, I hear some noise and only one of the speakers work, randomly every time I switch on and off, without changing anything else. After this threshold has been reached, I can turn down the volume again and everything works perfectly at any level.

You have most likely, an oxidised/pitted set of speaker relay contacts. Very, common.

The 'burst' of volume is required to 'cut through' the oxide and then all is well until next time or a period down the track.

Prior to turning it up, one speaker is lower in level and/or distorted.

To confirm it is the relay, take the cover off the amp, turn it on and play at the level where the issue occurs. Tap the speaker relay firmly with a wooden chopstick (safety first) and see if it instantly solves the issue. All you need do is either replace (preferable) the relay or alternately, remove it, pop the cover and clean the contacts with some 2000+ grit wet and dry cut into a thin streamer-like strip, folded over and pulled through the NO contacts.
 
OP
DonH56

DonH56

Master Contributor
Technical Expert
Forum Donor
Joined
Mar 15, 2016
Messages
7,835
Likes
16,497
Location
Monument, CO
You have most likely, an oxidised/pitted set of speaker relay contacts. Very, common.

The 'burst' of volume is required to 'cut through' the oxide and then all is well until next time or a period down the track.

Prior to turning it up, one speaker is lower in level and/or distorted.

To confirm it is the relay, take the cover off the amp, turn it on and play at the level where the issue occurs. Tap the speaker relay firmly with a wooden chopstick (safety first) and see if it instantly solves the issue. All you need do is either replace (preferable) the relay or alternately, remove it, pop the cover and clean the contacts with some 2000+ grit wet and dry cut into a thin streamer-like strip, folded over and pulled through the NO contacts.
Good catch, my amps have not had relays in years so I forgot about that. My solution for cleaning contacts "back then" was emery cloth. You can get it in sheets or spools.
 

Mnyb

Major Contributor
Forum Donor
Joined
Aug 14, 2019
Messages
2,645
Likes
3,624
Location
Sweden, Västerås
Wouldn't doing room correction (dirac, audyssey, etc.) make any differences in speaker cable length irrelevant? I'd also think that differences in room placement of each speaker would swamp the effects of small cable distance imbalance. Is that wrong?

Yes I would think the differences between L and R side of the room to dominate this ? And add the differences between L and R speaker.

But it’s good to know the magnitude off the problem and take action ( or not ) .
 

xaviescacs

Major Contributor
Forum Donor
Joined
Mar 23, 2021
Messages
1,494
Likes
1,971
Location
La Garriga, Barcelona
You have most likely, an oxidised/pitted set of speaker relay contacts. Very, common.

The 'burst' of volume is required to 'cut through' the oxide and then all is well until next time or a period down the track.

Prior to turning it up, one speaker is lower in level and/or distorted.

To confirm it is the relay, take the cover off the amp, turn it on and play at the level where the issue occurs. Tap the speaker relay firmly with a wooden chopstick (safety first) and see if it instantly solves the issue. All you need do is either replace (preferable) the relay or alternately, remove it, pop the cover and clean the contacts with some 2000+ grit wet and dry cut into a thin streamer-like strip, folded over and pulled through the NO contacts.
Thanks a lot. :) I've started this thread to stop polluting this one.
 

MKreroo

Active Member
Joined
Feb 21, 2020
Messages
143
Likes
67
this from Oratory might be a good addition to the thread
 

kongwee

Major Contributor
Joined
Jan 22, 2022
Messages
1,024
Likes
276
Longer mean increase resistance and reactance. Harmonic are different along the audio frequency. Already in textbook.
 

fpitas

Master Contributor
Forum Donor
Joined
Jul 7, 2022
Messages
9,885
Likes
14,191
Location
Northern Virginia, USA

fpitas

Master Contributor
Forum Donor
Joined
Jul 7, 2022
Messages
9,885
Likes
14,191
Location
Northern Virginia, USA
Longer mean increase resistance and reactance. Harmonic are different along the audio frequency. Already in textbook.
Yeah? That must be a very interesting textbook.
 

fpitas

Master Contributor
Forum Donor
Joined
Jul 7, 2022
Messages
9,885
Likes
14,191
Location
Northern Virginia, USA
Lol yeah. My bad
 

fpitas

Master Contributor
Forum Donor
Joined
Jul 7, 2022
Messages
9,885
Likes
14,191
Location
Northern Virginia, USA
i blame the delay in the unequal cables.
 
Top Bottom