Genz cab probs

[nojj]

Got back from a show on Sat, and my Genz top cab (500w 4x10) was breaking up on anything lower than the E.
Got through the gig,
and decided to see if I could maybe take care of the issue by swapping speakers with my elderly Genz 4x10 XB cab.
They're the same ones (GBE-1040-8) in both.
XO is.... shall we say......less robust in the top cab.
Speakers are creased all around where the reinforcement starts.
(Am I wrong in thinking over-excursion?)
I'm currently powering it with either an SWR 4004, or a Yorkie Bassmaster400.
(But used to run it from a Crown pwr amp, CE1000 I think)

I was also planning on swapping out the HF transducer for the heavier one from the XB,
and beefing up the internal XO with higher rated components.
(The XO from the XP got literally toasted a few years ago)

Assuming this all works out,
any recommendations on replacement speakers (hopefully neos) for the bottom 4x10,
and another XO?
I'd like something rated at 800w or so, but 600w should work.

Does Genz even carry replacement XO or heavier rated speakers like that?
(I'd like to keep everything reasonably close to stock.)

 

[will33]

Get ahold of Agedhorse, if he doesn't chime in here in a day or 2. Genz has recones available for most stuff, at least current production drivers.

Creasing is almost always a sign of overexcursion. Pumping too much lows to the cab.

 

[nojj]

Thanks Will, that's kinda what I thought.
looks like the cab is rated at 400w, not 500 as I originally thought.
Wonder if it's related to the re-wiring.
Might have to switch it back to original spec.
Got enough pieces parts on hand to build a more robust XO,
if I can fit the larger L-pad on the mounting plate, step it in a bit or something.

Speakers I just put in are the same, just much older.
Gotta say, the spkr wire clips on the new ones aren't anywhere near as well constructed as the old.

 

[agedhorse]

Creased cone edges at the surround is ALWAYS due to over-excursion. If your amp does not have adequate high pass filtering, and is rated above the rated continuous power of the cabinet, then it is entirely possible to damage the speakers. This is true of most speakers on the market, not just ours.

You mention rewiring the cabinet... what do you mean by this?

I may have recone kits available, I am on the road right now but will check. I need to know what the driver impedance is for your cabinet first.

The L-Pad is as large as anyone in the industry uses and we have so rarely seen one fail that it's unlikely yours is bad. Replacement crossovers should be available, but what's wrong with it?

 

[nojj]

Creased cone edges at the surround is ALWAYS due to over-excursion. If your amp does not have adequate high pass filtering, and is rated above the rated continuous power of the cabinet, then it is entirely possible to damage the speakers. This is true of most speakers on the market, not just ours.

You mention rewiring the cabinet... what do you mean by this?

I may have recone kits available, I am on the road right now but will check. I need to know what the driver impedance is for your cabinet first.

The L-Pad is as large as anyone in the industry uses and we have so rarely seen one fail that it's unlikely yours is bad. Replacement crossovers should be available, but what's wrong with it?

Hiya Agedhorse, good to talk with you again


imps on both sets of drivers are 8Ω, both cabs are stamped 8Ω,
top cab (a 4x10) is rated at 400w, the older XB is rated at 600w.
Cones are creased in the top cab, so I switched the drivers out from the larger cab,
and noticed that the speakers were the same.
The XB had a larger & heavier duty XO, caps were 250v, and so on, and the Lpad was larger.
(looked like maybe a 2nd order job as well)
The XB crossover got burnt a few years ago
(Literally, I lent it out, and got the thing back with a charred board, burnt wires and cracked resistors: write-off)
I wired the XB straight in (no XO) and was considering taking the few remaining usable parts from it,
to make the XO in the smaller cab more robust (it currently has a 100V cap & a small 30Ω resistor)
Was considering replacing the HF driver with the heavier one from the XB.
(Nothing wrong with the L-pads in either cab)

If you don't think it would make a difference, or if it could be detrimental,
I won't bother messing with the good XO.
Would like to have both cabs at the same relative wattage rating, though.
Then it would come closer to matching the newer rig currently residing in Eu for touring.
(GBE1200 & GB810T-UB)

So here's my questions:

What are the chances of finding a replacement XO for the older XB cab?
Anything I can do to increase the wattage rating in the smaller 400w cab to 600w?
Higher rated HF driver for the smaller cab?
Can I get recone kits and is this an at-home job or do I have to box and send 'em in?

IMO reconing would be a good option, I really like those speakers.

Oh yeah, how did you get the 410UB to a thousand watts?

 

[agedhorse]

Hiya Agedhorse, good to talk with you again


imps on both sets of drivers are 8Ω, both cabs are stamped 8Ω,
top cab (a 4x10) is rated at 400w, the older XB is rated at 600w.
Cones are creased in the top cab, so I switched the drivers out from the larger cab,
and noticed that the speakers were the same.
The XB had a larger & heavier duty XO, caps were 250v, and so on, and the Lpad was larger.
(looked like maybe a 2nd order job as well)
The XB crossover got burnt a few years ago
(Literally, I lent it out, and got the thing back with a charred board, burnt wires and cracked resistors: write-off)
I wired the XB straight in (no XO) and was considering taking the few remaining usable parts from it,
to make the XO in the smaller cab more robust (it currently has a 100V cap & a small 30Ω resistor)
Was considering replacing the HF driver with the heavier one from the XB.
(Nothing wrong with the L-pads in either cab)

If you don't think it would make a difference, or if it could be detrimental,
I won't bother messing with the good XO.
Would like to have both cabs at the same relative wattage rating, though.
Then it would come closer to matching the newer rig currently residing in Eu for touring.
(GBE1200 & GB810T-UB)

So here's my questions:

What are the chances of finding a replacement XO for the older XB cab?
Anything I can do to increase the wattage rating in the smaller 400w cab to 600w?
Higher rated HF driver for the smaller cab?
Can I get recone kits and is this an at-home job or do I have to box and send 'em in?

IMO reconing would be a good option, I really like those speakers.

Oh yeah, how did you get the 410UB to a thousand watts?

If you take a picture of the Xover and PM me, I will look into it. Note that you can't bypass the Xover and expect the HF driver to survive as it's the principle high pass filter for the HF driver.

The increase in power handling reflects the different tuning of the larger enclosure. The limitations are primarily mechanical in nature.

The HF driver's sensitivity and maximum output is matched to the rest of the cabinet. Changing it would require different crossover parameters and is beyond the scope of what I can provide.

Reconing is not a DIY sort of job. In fact, IMO the reconer needs to be skilled, experienced and detail oriented. I have seen too many poor jobs to trust anybody but a professional that has verifyable successful experience. Check the numbers on your drivers to see if one set is 1040 and the other is 1041 just to be sure. I am going from memory here and it's possible that there was a change either at this time or possible between later versions of the XB. I will look into your options.

The UB series uses a totally different (and MUCH more expensive) driver. This allows for additional tuning options that are not available with the original ceramic driver. This results in a higher rated power driver and cabinet.

 

[nojj]

If you take a picture of the Xover and PM me, I will look into it. Note that you can't bypass the Xover and expect the HF driver to survive as it's the principle high pass filter for the HF driver.

The increase in power handling reflects the different tuning of the larger enclosure. The limitations are primarily mechanical in nature.

The HF driver's sensitivity and maximum output is matched to the rest of the cabinet. Changing it would require different crossover parameters and is beyond the scope of what I can provide.

Reconing is not a DIY sort of job. In fact, IMO the reconer needs to be skilled, experienced and detail oriented. I have seen too many poor jobs to trust anybody but a professional that has verifyable successful experience. Check the numbers on your drivers to see if one set is 1040 and the other is 1041 just to be sure. I am going from memory here and it's possible that there was a change either at this time or possible between later versions of the XB. I will look into your options.

The UB series uses a totally different (and MUCH more expensive) driver. This allows for additional tuning options that are not available with the original ceramic driver. This results in a higher rated power driver and cabinet.

Thanks AH
I'll PM you some pix.
I had removed the HF driver from the XB cab, was using the cab as a sub on a bi-amp rig.
(Made a pretty nice plate to cover the hole.)
It's a tribute to you (& entire staff) that the drivers and horn came through unscathed,
as well as a few of the XO parts on the XB.
Kudos!!! That's why I prefer GB products.

Thanks for the heads-up on the mechanical limitations, and tuned system stuff.

Drivers for both cabs are GBE-1040-8
The XB cab is a pretty early model, maybe 1st year production run or so.
The other 4x10 is a KMC job.

I'll have to see if there's some qualified recone guys in Pittsburgh.
Most of the ones I know here do mostly home stereo foamies.

I suppose to move into the high-wattage realm for my US road work, might be better to get a couple UB cabs.
Move the original cabs (after repair) down to the studio/rehearsal room.
Won't be a popular decision with Wife of Nojj, who firmly believes I have more than enough gear already.

 

[will33]

Re: your crossover, 250V is a beefy cap and something you might use lower down in the bandwidth. The 100V should be plenty for a tweeter highpass, our signal just doesn't have that much energy up there to begin with.

Whoever fried yours had to be using a bunch of distortion/extreme treble boost/hitting it with way more power than was intended/had some problem with their amp, etc....or some lethal combination of those.

If they put a 250V on your other cab, it's probably for an added measure of protection/"foolproofing", or could be to save $$ ordering a big lot of 250V rather than small batches of various ratings. The 100V should be fine for anyone who knows what they're doing. 100 watt L-pad should be fine as well.


Long way of saying if you're a responsible user, I really don't see any return on investment by beefing up the filter more than it already is. If you rent out/loan out your gear to people you don't know, then maybe.

 

[agedhorse]

Re: your crossover, 250V is a beefy cap and something you might use lower down in the bandwidth. The 100V should be plenty for a tweeter highpass, our signal just doesn't have that much energy up there to begin with.

Whoever fried yours had to be using a bunch of distortion/extreme treble boost/hitting it with way more power than was intended/had some problem with their amp, etc....or some lethal combination of those.

If they put a 250V on your other cab, it's probably for an added measure of protection/"foolproofing", or could be to save $$ ordering a big lot of 250V rather than small batches of various ratings. The 100V should be fine for anyone who knows what they're doing. 100 watt L-pad should be fine as well.


Long way of saying if you're a responsible user, I really don't see any return on investment by beefing up the filter more than it already is. If you rent out/loan out your gear to people you don't know, then maybe.

It's not just the voltage of the series caps but also the dissipation factor that governs survivability under adverse conditions. Generally, the issue is driving the living snot out of an amp with heavy clipping and HF content that exceeds the capability of the entire speaker system.

 

[will33]

I guess that would fall under "foolproofing".


Not directed at the OP, but rather whatever fool burned up his cab.

 

[Stumbo]

Take a look at TBr fdeck's hpf/pre that will protect the very low end of your speakers and can be adjusted for each venue, if necessary. Maybe this will prevent what's already happened.

Here's a TB link: http://www.talkbass.com/forum/f15/fdecks-hpf-865291/

 

[nojj]

Probably a KB player
I don't lend my gear anymore..........

Just gonna wire the smaller cab the way it's supposed to be.
Probably shelve the bigger one till I get a clear plan of action.

What's the lower freq range on the GB-410T-XB and the GB-410T?
I'm not seeing any listings for them in the discontinued/archived section on the GB site.

Thanks for the link, Stumbo.

 

[will33]

Probably a KB player
I don't lend my gear anymore..........

Just gonna wire the smaller cab the way it's supposed to be.
Probably shelve the bigger one till I get a clear plan of action.

What's the lower freq range on the GB-410T-XB and the GB-410T?
I'm not seeing any listings for them in the discontinued/archived section on the GB site.

Thanks for the link, Stumbo.

The key here is the tuning frequency of the box, which you can find plenty close enough with the "dancing rice" sine wave test....search that.

The trick is not to not boost much below the tuning frequency as the box "loses control" of the cone down there. The other excursion peak is about an octave above the tuning frequency.

The box/speaker system is tuned to produce the desired sound in the bottom end and there really is no right or wrong, but asking a ported cab to produce below it's tuning frequency with appreciable power/volume can spell disaster if taken too far. It's a balance of mechanical and electrical abilities. A bit what Agedhorse was referring to regarding your different speakers having different ratings although they use the same driver.

 

[nojj]

Thanks for the explanation Will.

I was mainly concerned with accurate reproduction on the low side of a 5 or 6 string,
or possible repercussions from using some of the sub/oct patches on my XT Live.

Sounds like that HPF could be what the Doc ordered.
Where's my penny jar?

 

[agedhorse]

First of all, with regard to power compression there are several components to this. Thermal is only one component, there is also electro-magnetic and electro-mechanical components that come into play depending on the excursion versus average power. I have a test set that evaluates these non-linearities in a speaker system that gives a good indicator of the non-thermal components and thus a good indicator of power handling in LF applications where thermal is less of an issue.

Ok, the non-XB cabinet has a -10dB response that's probably close to 10Hz higher than the original XB and the XB2 and XB3 are maybe another 5Hz lower still. The non-XB is probably not the best choice for a 'fiver.

 

[nojj]

The non-XB is probably not the best choice for a 'fiver.

I was afraid of that.
No problem switching the drivers back in.
Could I swap the non-XB XO for the toasted one in the XB?
(non-xb is just a cap and resistor, XB one had a coil, several different caps and resistors on a pc board)
Or maybe just run it straight, with no HF driver installed.

 

[agedhorse]

The non-XB x-over matches up better with the non-XB tuning. You could run it without the tweeter if that's more your style. The opening for the tweeter needs to be blocked off, or leave the tweeter installed but remove the wiring to the x-over.

 

[will33]

Deleted some stuff there so as not to pull your thread completely off the tracks. Somebody probably think I was putting down their super cabs or somethin'.

 

[nojj]

The non-XB x-over matches up better with the non-XB tuning. You could run it without the tweeter if that's more your style. The opening for the tweeter needs to be blocked off, or leave the tweeter installed but remove the wiring to the x-over.

It's already blocked off, but I can easily put the HF back in.
How about if I build a crossover like the non-XB (1st order), but using the XB values?
Or will that require a 2nd order job w/ a coil, resistors and 2 different caps?
(Probably easier if I don't use the HF at all, problem solved....)

 

[agedhorse]

Totally different filters. Changing topology changes values.