cab diagnosis help...please

cracker75 · #1 04-29-2010, 01:00 PM

Hi all,

The more I read the less I know. I recently purchased two used/demo cabs from Dr. Bass, and they sound awful. I cannot figure out why.

One has a Bp102, and an Alpha 8MR and a tweeter. It came with the tweeter feed wired to pins 2+ and 2- to bi-amp with my GK head. Unfortunately it was also severely distorted at any volume. As per advice from another TB'r, I re-attached the tweeter leads to the (3-way) x-over and the distortion was replaced by hiss.

Other cab has a 12" Alpha 12LFA, and a tweeter, the filter network has no inductor, so I assume it's only a high pass, though I don't know at what frequency. It basically just sounds distorted/farty on any note played on the E string (as does the other cab). It was not wired to bi-amp.

Marc Serio (Dr. Bass) claims he replaced (upgraded)the 10", 8" mid, and the 12" (Which I believe because they were not spec), and so I think they may just need to be broken in, but don't really know.

I'm $500 into these things and can't stand the way they sound. I'm even contemplating building new boxes because he mounted the speakers with plain old wood screws, and may have torqued the frames (I'll be checking that later today).

I also plan on running woofers and tweeter only with the GK bi-amp, thereby bypassing the passive x-overs to see if taking them out of the signal path makes any improvement.

Otherwise I'm running out of ideas for a diagnosis.

Any help is appreciated.

seamonkey · #2 04-29-2010, 03:44 PM

Try breaking them in by running music high volume for 24hours.

Are they "custom" or stock?
Send them back if they're stock.

Don't buy custom on the internet. Lesson learned.
Sell them, buy what you need.

Eric Moesle · #3 04-29-2010, 08:23 PM

Whatever you do, DO NOT send them back to Dr. Bass or else you will be out your $$$ and will have no cabs. Plenty of stories of others here on TalkBass who returned non-conforming cabs for replacement, and never heard from Dr. Bass again. He'll keep your money AND your cabs.

Those speakers are not "upgrades" for anything. They are pretty much inferior to what usually comes in his standard cabs. Probably just using up whatever speakers he had laying around the shop. Perhaps they are damaged . . . its possible.

I'd suggest you take them to someone locally who is qualified to examine them for you and tell you what the problem is. You might have to replace the drivers or just the crossovers.

If the cabs themselves are damaged or built poorly you can at least sell them used provided you inform the buyer of the potential problems. At least you'd get something for them. Send them back to Dr. Bass and you get nothing.

Growly Lytes · #4 04-29-2010, 09:40 PM

Running in those speakers will do nothing.Breaking in speakers is a myth. You can run them at high volume for 2400 days & they will sound the same.
By the sound of what you say this Dr. Bass is no good.
BP102 is a great speaker period ! Poorly build cabs are not good for a speaker like the BP102.It needs a strong cab frame.Using wood screws doesnt help either.
I built two 410 cabs with BP102 & they will rumble any venue i play.

cracker75 · #5 04-30-2010, 12:22 AM

Quote:

Originally Posted by Eric Moesle

Whatever you do, DO NOT send them back to Dr. Bass or else you will be out your $$$ and will have no cabs. Plenty of stories of others here on TalkBass who returned non-conforming cabs for replacement, and never heard from Dr. Bass again. He'll keep your money AND your cabs.

My thoughts exactly.

I'm not sending them back. It was like pulling teeth just get them shipped. At least this way I have drivers and parts to build something out of.

seamonkey · #6 04-30-2010, 06:13 PM

Quote:

Originally Posted by Growly Lytes

Running in those speakers will do nothing.Breaking in speakers is a myth. You can run them at high volume for 2400 days & they will sound the same.
By the sound of what you say this Dr. Bass is no good.
BP102 is a great speaker period ! Poorly build cabs are not good for a speaker like the BP102.It needs a strong cab frame.Using wood screws doesnt help either.
I built two 410 cabs with BP102 & they will rumble any venue i play.

That's true for home stereo speakers, but pro speakers have stiff suspension out of the box.
Look at the surrounds and spiders of pro speakers compared to stereo speakers. There's no rubber surrounds in pro-gear.

Pro speakers will loosen up a bit after break in. But hardly any.

Growly Lytes · #7 04-30-2010, 10:27 PM

When i wrote to Eminence about the 8 BP102 that i had just purchased & put in two 410`s I asked them about `Running In` or `Breaking In` speakers they themselves said that its a myth.
They actaully said they have never heard of such a thing.So i just played them like normal & they sound great !

OxJohnson · #8 04-30-2010, 10:33 PM

I will double the point that "breaking in" is a myth... at least w/ regards to what you describe. There is something else going on there...

Ox.

cracker75 · #9 05-01-2010, 12:38 AM

Quote:

Originally Posted by OxJohnson

I will double the point that "breaking in" is a myth... at least w/ regards to what you describe. There is something else going on there...

Ox.

I'm choosing to believe the myth for now, and will begin the break-in process tomorrow. I am also looking to seal the cabs better and stuff them better to try and get a tolerable sound.

Should that succeed I'll be purchasing some plans from Bill Fitzmuarice, and start considering my own build.

Right now I have more questions than answers.

I suspect there may be some wiring issues too, but I need to learn more before I could even begin to suggest what they might be.

Thanks for all the replies guys, I will update this thread as things evolve.

billfitzmaurice · #10 05-01-2010, 07:14 AM

Quote:

Originally Posted by Growly Lytes

When i wrote to Eminence about the 8 BP102 that i had just purchased & put in two 410`s I asked them about `Running In` or `Breaking In` speakers they themselves said that its a myth.
They actaully said they have never heard of such a thing.

No one in the engineering department at Eminence would give that reply. Perhaps your response came from someone on the loading dock crew.

OTOH drivers that have not been broken in would not explain any of the OPs problems.

Growly Lytes · #11 05-01-2010, 08:30 PM

I still have the email that was sent to me by Anthony Lucas @ Eminence. He wrote that he has `never` heard of that before so like i said i just played them like normal & the sound is not changing with playing.If you email them they will write the same back trust me i tried it because i was going to `Run` them in before A.L said its a bunch of crap.

billfitzmaurice · #12 05-02-2010, 09:31 AM

Quote:

Originally Posted by Growly Lytes

I still have the email that was sent to me by Anthony Lucas @ Eminence. He wrote that he has `never` heard of that before so like i said i just played them like normal & the sound is not changing with playing.If you email them they will write the same back trust me i tried it because i was going to `Run` them in before A.L said its a bunch of crap.

I have no idea who Anthony Lucas is. I only deal with two guys at Eminence, Jerry (the head engineer) and Chris (the president).

BassmanPaul · #13 05-02-2010, 09:55 AM

Quote:

Originally Posted by billfitzmaurice

I have no idea who Anthony Lucas is. I only deal with two guys at Eminence, Jerry (the head engineer) and Chris (the president).

Name dropper!!!

BassmanPaul · #14 05-02-2010, 09:59 AM

Quote:

Originally Posted by cracker75

I have drivers and parts to build something out of.

I have a feeling that you have faulty or more likely damaged drivers so even this option is questionable.

Paul

Tim C. · #15 05-02-2010, 04:31 PM

Quote:

Originally Posted by Growly Lytes

I still have the email that was sent to me by Anthony Lucas @ Eminence. He wrote that he has `never` heard of that before so like i said i just played them like normal & the sound is not changing with playing.If you email them they will write the same back trust me i tried it because i was going to `Run` them in before A.L said its a bunch of crap.

You know, about a month ago somebody let a young child operate an air traffic control station. You never know who you're really talking to these days - I'd take Bill M's advice.

cracker75 · #16 05-02-2010, 04:54 PM

Quote:

Originally Posted by BassmanPaul

I have a feeling that you have faulty or more likely damaged drivers so even this option is questionable.

Paul

Any thoughts on how to determine if they're damaged?

I tried the "push test" to check if there was any resistance/friction or rubbing between cone and voice-coil, everything seemed OK.

I broke down and bought a voltmeter under the assumption that I can learn enough about x-overs to diagnose if that is where the problem lies.

LOL> Wish me luck.

Andyman001 · #17 05-02-2010, 05:51 PM

By-pass the crossover and test one speaker at a time, don't go crazy with the volume/gain knob though

Growly Lytes · #18 05-02-2010, 09:17 PM

Anthony Lucas
Technical Support
Eminence Speaker LLC
anthony.lucas@eminence.com
502-845-5622 ext. 341
When was the last time you wrote to Eminence because ive emailed them about 5 times in the past year & Anthony Lucas is the person who writes back.

M0ses · #19 05-02-2010, 09:22 PM

Your first mistake was thinking about buying from Dr. Bass.
Your second mistake was actually doing it.
IMHO someone who gives Dr. Bass their money deserves whatever they get, as long as it's not good cabs.

cracker75 · #20 05-05-2010, 08:17 PM

Quote:

Originally Posted by M0ses

Your first mistake was thinking about buying from Dr. Bass.
Your second mistake was actually doing it.
IMHO someone who gives Dr. Bass their money deserves whatever they get, as long as it's not good cabs.

Thanks Moses, that was so helpful.