Neo replacement 15" for an old GK 115RBH???

[thejumpcat]

The cabinet is in good shape, and so is the speaker, but it's soooo heavy. I think it's about 65 pounds. I'd like to put a neo speaker in there to lighten it up. Any recommendations?
Thanks!

[thejumpcat]

I've spent a couple of hours today researching various 15" speakers. I'm pretty ignorant on this stuff. I have a GK 400RB head that can put out 200 watts at 4 ohms. The speaker that's in the cab is 8 ohm. So, to get the max output, should I get a 4 ohm speaker?

Here's what I found on my cabinet:

GK 115RBS
200W
8 Ohms
Rear Port
Dimensions: 23''W 23''H 18''D
Weight: 60 lbs
Covering:Black Carpet
Construction: ¾ '' Grain Oriented Strand Board
Removable Castors:Yes
Woofer: 1x15B200-8
Input: ¼ in full range Yes

Here are several 4 ohm speakers I saw at US Speakers:

Jensen Neodymium 15" bass guitar speakers - Jensen Neo15-150 15" bass speaker has a lightweight neodymium magnet. Great tone for bass guitar cabinets with full detailed sound and handles 300 watts.

15" Bass Guitar Speakers - Eminence CA15-4 15" 4 Ohm Bass Speaker - Eminence Legend CA15-4 is a 4 ohm 15" bass guitar speaker. The Eminence Legend CA15-4 is a great upgrade or replacement 15" bass speaker for bass guitar cabinets.

Eminence Kappa Lite 3015LF bass guitar speakers - Eminence KappaLite 3015LF 15" lightweight neodymium bass guitar speaker. Eminence Kappa Lite 3015LF lightweight bass guitar speakers.

B&C 15 HPL76W is a 15" lightweight high power woofer - B&C 15HPL76W Speakers - B&C neodymium 15" high power speaker for 2 or 3-way systems. B&C 15HPL76W neodymium high power bass speakers available now.

Or am I wrong in thinking 4 ohm? Would an 8 be OK?

I know nothing about matching a speaker to a cabinet or 'tuning' a cabinet. Help me out here, guys. My goal is to lighten the load and take advantage of all the head's power.

[Windreaper]

Ok,

that cab is ported so you need to measure total port area and length (or just post the port dimensions and the number of ports). Also, approximate the total cab volume, should be roughly 3.5cf I think. I can then model the cab for you and post the simulated low end response.

If you are going to disregard the above advice and will just pop in a random driver, I would recommend the Eminence Kappalite 3015 (not the LF version). Should result in a pretty flat response if that cab is tuned in the 45-50Hz region.

[thejumpcat]

Thanks, Windreaper!
Just one port -- 5.5" long and 5.5" in diameter -- right in the middle of the back.

I just took the speaker out and weighed it on my bathroom scale: 5 pounds! That kinda blew my mind. I think it's the original GK speaker.

[RickenBoogie]

First, you will get very little weight reduction changing the speaker, the weight is in the cab, and secondly, you gain almost nothing by going 4 ohm over 8 ohm with a single driver cab. Much better to just add another 8 ohm 1x15 to what you have for a 6dB increase.

[thejumpcat]

Again, I'm ignorant, but wouldn't I get more out of the head at 4 ohms than 8?

[Windreaper]

Originally Posted by thejumpcat

Again, I'm ignorant, but wouldn't I get more out of the head at 4 ohms than 8?

Well, technically yes but it is complicated. If you want more volume you are usually better off getting more speakers. I would have to second Rickenboogie in this case, there is not much to gain here, I would save my money if I were you. You won't save any weight and won't gain much if any volume by swapping the driver. If you like how your cab sounds, I would keep it as it is.

EDIT: Removed graph to avoid confusing anyone.