One Speaker Quieter Than The Other?

amplifiers, receivers and loudspeakers
digthispig222
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One Speaker Quieter Than The Other?

Post by digthispig222 » 01 Dec 2019 20:23

I know there are already tons of topics like this online, but I haven't found any fixes (if they can be done) in those forum posts. Anyway, I found a pair of Soundesign 0619 speakers under my work table that came with a Soundesign 5751 stereo system, and one appears to be quieter than the other. Now I know what you're thinking: "These speakers probably aren't worth it given the brand name." You may be correct, but I still maybe they'd be fun to play around with. I'm thinking the one speaker that's quieter might've been damaged, but I could be wrong. Does anybody have any other theories as to what could be wrong and possibly how to fix? I've tried them with multiple receivers and ensured the balance was set in the middle. Same results every time.

paddypaws
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Re: One Speaker Quieter Than The Other?

Post by paddypaws » 01 Dec 2019 20:42

It’s seems that you have narrowed it down to a particular speaker being quieter so we can rule out the amp. The quickest way to fault find is to swap parts between speakers to see what part takes the fault with it. Swap the tweeter and try it again then the woofer then the crossover. You’ll soon find which part is faulty and then if it can be repaired. Might just be a poor internal connection.

digthispig222
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Re: One Speaker Quieter Than The Other?

Post by digthispig222 » 01 Dec 2019 21:10

Sounds like a good thing to do, but there's one problem: they're sealed with some glue at the back. I'm kind of afraid I'd tear them up just trying to take the back off (even though they're probably not worth much to begin with). Is there a way to remove that glue or anything?

paddypaws
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Re: One Speaker Quieter Than The Other?

Post by paddypaws » 01 Dec 2019 21:17

Just about every speaker I’ve seen (well 99%) load from the front, when the grills come off you should see screws in the speakers basket and be able to take everything out from there.

digthispig222
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Re: One Speaker Quieter Than The Other?

Post by digthispig222 » 01 Dec 2019 21:44

Okay, so maybe I could get better help opening these up by showing you guys a picture. Here they are:
Attachments
20191201_164018.jpg
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lenjack
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Re: One Speaker Quieter Than The Other?

Post by lenjack » 01 Dec 2019 22:49

If you can, swap the left right connections, from the back of the receiver to the speakers. If the quieter speaker is now the other one, then the problem, is in the electronics, not the speakers.

paddypaws
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Re: One Speaker Quieter Than The Other?

Post by paddypaws » 01 Dec 2019 23:16

lenjack wrote:
01 Dec 2019 22:49
If you can, swap the left right connections, from the back of the receiver to the speakers. If the quieter speaker is now the other one, then the problem, is in the electronics, not the speakers.
He already swapped the amp you didn’t read the original post did you?

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Re: One Speaker Quieter Than The Other?

Post by lenjack » 01 Dec 2019 23:20

I did, but I missed it. #-o :cry: :oops: What shall I do for penance?

paddypaws
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Re: One Speaker Quieter Than The Other?

Post by paddypaws » 01 Dec 2019 23:27

Lenjack 🏑 maybe a smack round the face with a hockey stick? :lol:

Yeah with those speakers you’ll have to prize the back off and glue it on again after. Those drivers will probably be glued in from the back. Those are really unlikely to be worth fixing, however it’s likely just a loose connection or a dirty spade terminal. They’re not going to sound good with plastic boxes and what looks like a piezo tweeter. Unlikely they’ll even have a crossover. You could pick up a pair of decent vintage wharfdale diamonds or something for Very little money, unless you are just doing this out of interest.

digthispig222
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Re: One Speaker Quieter Than The Other?

Post by digthispig222 » 02 Dec 2019 02:56

Ok so I got inside of it and had a look around. That piezo tweeter you mentioned? There isn't any! That part is just for decoration (this applies to the working speaker as well.) I tried everything I can think of: checked connections, cleaned the spades, cleaned the RCA plug on the outside, cutting the RCA plug off entirely and wiring it direct to the receiver I was using, and even replacing all the wiring entirely with my own, but to no avail. Is it safe to assume my hypothesis about the driver somehow being damaged correct, or is there anything else I can do?

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Re: One Speaker Quieter Than The Other?

Post by aardvarkash10 » 02 Dec 2019 07:03

measure the speaker resistance to confirm a difference. Ideally do this by measuring the current through the winding using a 1.5v battery as a voltage source. You should get around 200mA if they are 8-ohm impedance speakers, but more important is that they are the same. If you wanted to get really techie, you could measure the excursion using the same 1.5v battery - the cone should move the same distance on each speaker. Check in both directions by reversing the battery.

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Re: One Speaker Quieter Than The Other?

Post by UsableThought » 02 Dec 2019 07:10

digthispig222 wrote:
02 Dec 2019 02:56
Is it safe to assume my hypothesis about the driver somehow being damaged correct, or is there anything else I can do?
So you are dealing with a single woofer in each speaker - no crossover, no tweeter, etc. And you have tried wiring direct to the leads on the speaker, without getting any improvement in loudness; and previously have swapped amps to eliminate the amp as the problem. That leaves the speaker itself.

If damage to either the voice coil or cone were involved, it seems likely the symptom would be poor sound quality rather than lack of comparable loudness.

My thought is, maybe it’s a weak magnet in that speaker. Googling doesn’t bring up much, but see this thread (link below) from a guitar electronics forum - at least one of the replies in that thread is from a small-time speaker manufacturer (J M Fahey) who also has an EE degree, and so speaks with a good deal of credibility:

https://music-electronics-forum.com/sho ... hp?t=25319

You’ll see the original poster in that thread did a simple comparison test for magnet strength; you could try the same. Measuring the DC resistance of the speaker, as suggested by aardvarkash10, would also be interesting to try. Speaker excursion ditto.

However although such tests might be of interest in satisfying curiosity (i.e. you might discover a measurable difference of some sort) it’s unlikely you would then be able to use the information to fix the speaker at reasonable cost. My own experience with junk speakers is, easy come, easy go.

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Re: One Speaker Quieter Than The Other?

Post by Tinkaroo » 02 Dec 2019 09:49

It could be the speakers have been damaged over the years, but are probably not worth investing a lot of money and effort into.

You would be better off finding a better quality small speaker such as a Realistic Minimus 7 or any true 2 way bookshelf speaker. You can usually find something half decent for a reasonable price.

Truthfully Soundesign doesn't have a very good reputation in the audio field for quality, and the fact they faked the tweeter on this speaker just reinforces that reputation. #-o

lenjack
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Re: One Speaker Quieter Than The Other?

Post by lenjack » 02 Dec 2019 14:33

Not only did they fake it, they tried to make it look like an expensive tweeter.

digthispig222
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Re: One Speaker Quieter Than The Other?

Post by digthispig222 » 02 Dec 2019 20:34

So after reading some of these responses, I'm thinking maybe I should look at the magnet. Does anybody know of a non-destructive way to get the magnet off?

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