Figuring out speaker properties + Building enclosure

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Hey everyone Completely new to building audio stuff, sorry for the wall of text ahead of time - lots of noob questions

I have two 15" GBS 1566 subwoofer chassis that fell into my lap, and i have no clue what exactly their properties are - can't find much info on the internet either.

Screenshot - 94d85bb81e40abe6602200b1d63c5edc - Gyazo Screenshot - ddb04cc11e05e655d6e72bee5ebc6dce - Gyazo

Some general questions i have are, how would i best clean these? The guy i got them from said they were sitting around for a good while, the back side of the cone and the inside of the surround is super dirty - just wipe with wet towel? the backside of the cone feels like paper mache and i am worried that they could get deformed when wet? I also assume there is some dirt inside the magnet gap and the little vent on the back - can i just remove the shiny plate? Is that just shielding or will the motor fall apart if i do that and force me to re-align everything?

Things i know about them are that they have dual 4 Ohm voice coils (3" i think) and have 1000W printed on them. I found some dodgy info online stating they do 600W rms but that is about it

I haven't dared to turn them past around 300W RMS each because the free air excursions at some frequencies are enormous and i am worried of smashing the voice coil into the magnet.
On one of them one of the tinsel leads smacks into the back of the cone at higher powers, barely happens when playing music but very noticeable on raw sinewaves - any recommendations on how to fix that?

The dustcap on one of them is slightly peeling off (still sealed and seems solid, just a spot that got unglued) - any glue recommended for fixing this?

i didn't do an exact measurement on this yet but they appear to resonate somewhere between 30 and 31hz, I estimate the Xmax to be slightly over 30mm but i am not certain on that, not sure how to measure it either.

How would i go about determining the properties of the chassis or size for a sealed box? I want to build two seperate sealed sub enclosures, maybe build something horn loaded later. I also considered Dipole but i think i'd rather have stereo bass. They will be mostly used for music.

I also want to change color of the cone and the surround at some point, can i just get an off the shelf black 15" surround and replace the blue one on these? I'd spray paint or airbrush the cones themselves since it's not like i am messing up any special characteristics by slightly increasing cone mass, given there are no specs anyways.
 
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Welcome ledman!

Here are some answers for starters:

Do not wet the cones - remove dust with a soft brush only.

Do not touch the vent - hopefully no dust has got into the gap - for experts only!

Do not test the drivers at high power if not mounted in a cabinet, and certainly not with sine waves - you will overload the speaker (hence the tinsel lead smacks!).

Use Aileen's tacky glue, or similar, on dustcap.
 
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Alright cool
yeah i figured if it doesn't sound right it probably isn't right.
Any rough volume figures i can use for a test cabinet build?
(thinking a test cabinet made of particle board because it's basically free)

I do have experience in constructing various things, and have a good amount of metal and woodworking tools available, could also CNC some stuff.

I am pretty convinced whatever is on the surround has also gotten into that vent given how the insides of the surround look
you can see on the left how it's basically brown instead of blue like on the right Screenshot - a80d55bee8cf1cca51775789f33ffe5c - Gyazo
it is very fine sticky dust, doesn't feel very abrasive though.

So the 6 bolts on the back with the plate actually clamp the magnet to the frame?
 
If there was any contamination in the magnet gap, you would hear a scraping sound as you gently push on the woofer cone. If not, then leave well enough alone.

I would not undo those bolts for the reasons you, yourself, have stated!

Use a test cabinet volume of at least 2 cubic feet for one 15" driver..

We would need to know the specifications of the driver to design a final enclosure - the only references I can find are in German (picclick.de) but no parameters are given.
 
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Thanks for the advice so far.
I am not sure what you mean MAAC0, in which orientation? just zip ties to the headrest?
Yeah I know they are car subs - i am not going to use them in a car though.
They will be driven by a Crown 1400 CSL and annoy my neighbors

I don't have a datasheet for them either, will measure them as described here the next few days.

Will build a 60L cabinet and see what happens
 
Alright so i built two enclosures from 19mm particleboard
Screenshot - f6af7050679fd4ffefd609125bd0773b - Gyazo
Screenshot - 59cbbf7db3f644f2cc78c951aec9f0ee - Gyazo

The drivers came with this rubbery gasket/decoupler thing, i didn't have anything else on hand so i used some washers and wood screws to bolt the them in, don't like the way i had to squeeze it down to have a seal - any recommendations to get this to seal properly without feeling absolutely wrong? ring/trim over the whole rim to apply even pressure?
Screenshot - 1763509f110341c359edd8c0b7259af9 - Gyazo

I am still getting the tinsel smack on one of the drivers, even at fairly low levels - the tinsel lead in question is very close to the membrane by default (maybe 1mm gap, it's as if it is bent the wrong way, keeps going back into that position)

can i use some kind of glue to change the angle at which it sticks out of the membrane?
 
I am still getting the tinsel smack on one of the drivers, even at fairly low levels - the tinsel lead in question is very close to the membrane by default (maybe 1mm gap, it's as if it is bent the wrong way, keeps going back into that position)

can i use some kind of glue to change the angle at which it sticks out of the membrane?

Use a proper mounting gasket on the rear flange.

These folks have an assortment of quick setting glues: Aleene’s Glue Products | Craft & DIY Project Adhesives - Industrial Strength Glue

GM
 
A common problem with cheaper drivers...
I wish i knew how much these were and if they were actually cheap or if they are just kinda bad - certainly the company no longer exists lol.
I got them for 30€ and they aren't broken so can't exactly complain

So i can use the Aleene 's Tacky glue i already ordered on the tinsel lead as well?

Where would i buy some mounting gaskets (europe)?
I mostly find the tape you glue down from the usual scumbags on ebay

I am going on vacation tomorrow and won't be back for 3 weeks, so will have to wait with everything anyways
 
The ebay price for one sub was EUR 130.

I wonder why the front surrounds are so squidgy? Anyone know? Your idea of making a solid ring to go on top sounds a good one.

Aleen's tacky glue won't do for the tinsel lead - you need something more substantial to build up into a cone and head the tinsel lead out in the required direction - like Granville Black (or Clear) Silicone Sealant from a car accessories store.

You could make rear gaskets from card - use several curved sections to cover the entire circumference. I've seen old drivers mounted in this way - better seal than just metal to wood.

Happy holidays!
 
Digging this thread up again because i finally got time and actual reason to deal with these.

I have been running these speakers in the test enclosures i had built since i posted them, and they have been doing fine, so this project kinda ended up on hold because i was sufficiently satisfied with how they have been working and just kept pushing it aside in favour of other stuff.

However, one of them has been starting to crackle at a certain amplitude and frequency, most prominent at 60Hz, it appears to be only caused by one of the voice coils, if I only drive the other coil it sounds perfectly fine.

The coil that is fine measures in at 3.9 Ohm DC resistance, the one that is dodgy at around 4.4Ohms DC resistance but the measurement is super jumpy.

It's almost as if there is a wonky connection where the tinsel lead is connected to the VC that starts causing crackling as the amplitude gets large enough.

So i am tempted to take off the magnet to see if i can spot any damage on the VC.
Any tips i should watch out for before i do this?
spider and surround are glued in so getting into this thing from that end is not going to be as easy, i might be able to pull off the dustcap.

I have done some measurements on the speaker that appears to be damaged, have yet to do the other one.
I went with this page T-S Parameter Calculator
This is what i got from the driver (it sounds and acts fine at low volume)

I am not entirely sure how to measure cone diameter - i would say it is 28cm
But i read somewhere that you should measure about 1/3 over the surround so my cone diameter could be 30cm, I included Vas for either.

I don't have an amplifier that won't go into DC protect at 1Hz so i measured DC resistance with the DMM at 7Ohm, but the measurement was jumping around up to 8.5 Ohm

I will take the other driver out of the enclosure tomorrow and run the same test for comparison

Qms=7.653781
Qes=0.391069
Qts=0.372059
Cms=0.00023074 m/N
Vas(28cm)=122.478995 L
Vas(30cm)=161.40408 L
EBP=61.370231
 
In auto sound installs tinsel leads over time fail all the time. Sometimes they are welded, soldered, even crimped onto the coils leads. I've had them break at almost every location. Including all of the tiny flat ribbon strands all shearing apart, but visually still held together by the center filaments.

Your 30mm of testing may have cooked an already abused (previous owner) VC. Although you did express concerns of contamination getting in the motor assy. Doesn't take much to grid-out a VC when you pushing lots-o-power and there's debris in the gap. Due to all kind of causes the VC doesn't stay perfectly centered in the gap at high excursions.

BTW, if you're pushing HT/music subs to 30mm (even pk-pk) on a normal basis - it might be time to double down on qty (or even quadruple the amount). Speakers last a lot longer when used at less than WAR Volumes!
 
So it's fixed.
Any recommendations for an enclosure?

Before i went to literally disassemble the whole speaker i did a closer inspection of the tinsel leads at the terminals and noticed how one of them was a tad too flexible, pushed low power 30Hz sine into it and wiggled that lead - and the scratchy popping came back.

Desoldered the lead, clipped the end off, soldered it back on and it's working fine again.

Consider the T/S parameters i posted as ballpark for now, any recommendations for an enclosure?

I was not very accurate when i sweeped with the frequency, used my phone as a signal generator and just verified the frequency with the scope, only did integer increments.
Is that close enough or should i put more care into this?
How important is precision here?
 
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