Jensen MOD 32 ohm for GK BLX?

Ortus · #1 07-06-2011, 05:10 PM

I have a GK BLX 410 cab with a blown speaker. These cabs have four 32 ohm speakers in them. Not positive what the cab's power rating is--the GK site says 400 watts but not sure if this is accurate, and I think my cab may be an older version (it's the one with the red writing).

There is a Jensen MOD speaker on the market that is 32 ohm but rated at only 50 watts. Most other 10" 32 ohm speakers I see for sale are rated between 100 and 200 watts, including the GK replacement on their site I use this cab with an old-style GK 400rb head and play at moderate volume (both master and gain turned up 50%, tone controls mostly flat or slightly cut).

I leave this rig at a club where I play a weekly cover gig. It is basically a functional, knock-around rig I used got for cheap so I wouldn't have to lug my gear every week at 3am. In other words, I am looking for the absolute cheapest way to replace the speaker, but I also don't want to have to replace it again in a month.

Will this Jensen cut it? Is there any reason I shouldn't have one speaker rated at 50 watts while the other three are rated higher? Here's the link:

Fliptops

username1 · #2 07-06-2011, 05:22 PM

I would go with the eminence legend b810. It handles 3 times the power, has a much better xmax and is also 32ohm and it is only about $75.

Ortus · #3 07-06-2011, 06:04 PM

Awesome thanks--will definitely check that out! I guess though, what I really want to know is: is there any reason the cheap $40 Jensen WON'T work in this set up?

JimmyM · #4 07-06-2011, 07:48 PM

As long as you remember that the Mod is your weak link for volume and low end and will blow easier than the GK speakers if you're not careful, it'll work.

4Mal · #5 07-06-2011, 07:52 PM

The jensen is a Guitar speaker. Not a very good one at that. I'd take a pass and do the BP102 ...

billfitzmaurice · #6 07-06-2011, 08:21 PM

Quote:

Originally Posted by Ortus

Is there any reason I shouldn't have one speaker rated at 50 watts while the other three are rated higher?

The thermal power rating is moot. What counts is the displacement limited power capacity, which is about 15 watts for the Mod, 50 watts for the B810.

JimmyM · #7 07-06-2011, 09:07 PM

15 watts??? I thought you always said you could get about the same performance as the old CTS's, which were real world rated (for 1969) at 250w in an 810. Or does the porting of the GK cab bring that figure down a lot?

okabass · #8 07-07-2011, 06:47 AM

I think your cab is sealed, like half of the the "Fridge".

I used those MOD's for my 8x10" SVT clone. They work surprisingly well with my 300 W SVT clone. No bottoming at all. Especially mids and highs are very pleasing.

Now I'm using six Eminence B810 plus two MOD's at the upper compartment. The Eminence's low-range is better than MOD's, but MOD's have better mids and highs.

Technically B810 is better speaker but MOD's sound and work better than the specs say.

I'd try to ask GK what's their advice.

billfitzmaurice · #9 07-07-2011, 07:06 AM

Quote:

Originally Posted by JimmyM

15 watts??? I thought you always said you could get about the same performance as the old CTS's,

The CTS had a real world 240w thermal rating, not displacement. That's why two 69 Fridges were required to handle the 300w head cleanly.

Quote:

I used those MOD's for my 8x10" SVT clone. They work surprisinly well with my 300 W SVT clone. No bottoming at all

Bottoming is the result of the driver reaching xlim, not xmax. Most guitar drivers have a very high xlim to xmax ratio, at least 5:1, so bottoming out a guitar driver is very rare. But any power applied beyond the displacement limit ends up as heat, not additional output.
Keep in mind that it takes a 10dB increase in output to sound twice as loud, so while 15 watts displacement seems quite low it will take 150 watts displacement to sound twice as loud. That's why very low displacement drivers don't seem to be as output shy as the displacement figures might indicate. But if you run the same power into a Mod 10 loaded cab versus a BP102 loaded cab, which is at the opposite end of the displacement spectrum, the difference in the low end output will be very obvious, as will that in the mids, because as displacement goes up midrange response goes down.

JimmyM · #10 07-07-2011, 07:18 AM

Well you're the expert Bill, but I'll tell you...I've whomped the crap out of those speakers occasionally and they were fine. Still, you're pretty infallible when it comes to matters like this, so I probably won't be doing that again

billfitzmaurice · #11 07-07-2011, 07:43 AM

Quote:

Originally Posted by JimmyM

.I've whomped the crap out of those speakers occasionally and they were fine.

That's due to the high xlim/xmax ratio. You'll toast a coil long before you'll bottom out a guitar driver. OTOH most bass drivers have only a 2:1 xlim/xmax ratio. Some with high xmax figures have less than that, so they will suffer creased cones and slammed coils even when the thermal rating isn't exceeded.

okabass · #12 07-07-2011, 12:12 PM

Quote:

Originally Posted by billfitzmaurice

The CTS had a real world 240w thermal rating, not displacement. That's why two 69 Fridges were required to handle the 300w head cleanly.

Bottoming is the result of the driver reaching xlim, not xmax. Most guitar drivers have a very high xlim to xmax ratio, at least 5:1, so bottoming out a guitar driver is very rare. But any power applied beyond the displacement limit ends up as heat, not additional output.
Keep in mind that it takes a 10dB increase in output to sound twice as loud, so while 15 watts displacement seems quite low it will take 150 watts displacement to sound twice as loud. That's why very low displacement drivers don't seem to be as output shy as the displacement figures might indicate. But if you run the same power into a Mod 10 loaded cab versus a BP102 loaded cab, which is at the opposite end of the displacement spectrum, the difference in the low end output will be very obvious, as will that in the mids, because as displacement goes up midrange response goes down.

Ok, thanks. That explains what I experienced with the MOD's.
B810's low range is so much better, that I now have the "bass" on 12 o'clock. With the MOD's it was at 3 o'clock. The difference is about 9 dB. And the bass seems still fuller now.
I do feel that the MOD's have better mids and highs. I think the combination is the answere.

Ortus · #13 07-07-2011, 04:16 PM

So in other words, am I correct in saying that if I have one Jensen out of four in the cab, there's not a huge danger of blowing it out at moderate volume/bass eq, but I may notice some decreased bass response and perceived volume?

billfitzmaurice · #14 07-07-2011, 04:17 PM

Quote:

Originally Posted by Ortus

So in other words, am I correct in saying that if I have one Jensen out of four in the cab, there's not a huge danger of blowing it out at moderate volume/bass eq, but I may notice some decreased bass response and perceived volume?

That would probably be the case.