What speaker

[tramp]

I have a Fender Bassman 150 with a 4 ohm 12 inch Eminence speaker. I think the speaker is going out. There is some fuzz sound when I hit low notes. What should I get for a good balance between mids and lows.

[Thumpking]

EV EVM series baby. best speaker on the market IMHO. Expensive, but so worth it.

[1n3]

I have this amp, and have considered a replacement speaker for it. I contacted both Fender and Eminence for specs on the speaker. I've measured the cabinet, and used WinISD to compare some possible replacement speakers to the original. One problem in finding a replacement is, 4 ohm 12" retail bass speakers are rare. So I only looked at 8 ohm Eminence speakers.

My recommendation is the Basslite S2012. It performs well in that cabinet, the thermal power rating matches the amp, and it's cheaper than a Deltalite or Kappalite. Last but not least, the bolt hole circle matches the original; the others don't.

As for the EVM, I can't say; don't have a model of that, and wouldn't have any interest in getting one. Heavy, pricey, and more of a guitar speaker, AFAIK.

Before you buy a new speaker, check to see that the speaker is tight to the baffle. And if you replace the speaker, I recommend you line the interior of the cabinet while you're at it.

[tramp]

1n3 - How does the 8 ohm effect the proformance of the amp? If it came with a 4 ohm, shouldn't you put another 4 ohm in it? Does the 8ohm reduce the output?

[rpsands]

It won't reduce your maximum output as:
1- the basslite is probably louder than the amp in there
2- neither woofer can take the entire 100w @ 8 ohms, much less the 150 watts @ 4 ohms, without potential for exceeding xmax.

[1n3]

Originally Posted by tramp

1n3 - How does the 8 ohm effect the proformance of the amp? If it came with a 4 ohm, shouldn't you put another 4 ohm in it? Does the 8ohm reduce the output?

Yes, an 8 ohm speaker will draw less power than a 4 ohm speaker. That will reduce amp output, but that's not bad for the amp, and that's not the end of the story. Put simply, I'd expect the Basslite to be almost as loud as the original speaker; maybe even a little louder below 60hz. Put more technically...

I can't make good comparisons because I have low confidence in the accuracy of my OEM speaker model. The specs I received from Eminence don't match up in WinISD very well. To resolve conflicts between parameters, I had to let some float significantly away from their stated value. I would say that the OEM speaker most closely resembles an Alpha 12, but I don't think the Alpha is a good proxy for modeling.

Stated sensitivity for the OEM speaker is 94.3dB, vs 97dB for the Basslite. On paper, the 2.7dB increase in sensitivity makes up most of the power loss for going from 4 to 8 ohm. In that cab, the OEM speaker models as more sensitive from 80-500hz, but I discount that, because my OEM driver model is inaccurate, and there's the matter of excursion.

The Basslite has an Xmax of 5.2mm. WinISD shows excursion-limited power for the Basslite dipping to 120W at ~73hz, and falling below thermal again at 34hz. It should be quite safe with an amp rated for 150w at 4 ohms.

I can't tell with any accuracy what excursion-limited power is for the OEM speaker, but it's probably much lower than the Basslite. Eminence gives Xmax for the OEM speaker as 0.47 mm; Fender gives it as .019 (inches, I assume; = 0.48mm). That's pathetically low. So low, in fact, that it's hard to believe. The Alpha 12a has an Xmax of 2.4mm; I'd think this speaker would be closer to that.

But I'll say this - I once gigged this amp outdoors without PA support (there was supposed to be), and it did OK. A little fartage, but not bad. Now, this was in a good ampitheatre with a low-volume jazz band, and I wasn't going for big low end. But the amp was pretty hot afterward, so I know I pushed it.

In general, I like the amp, but if I can pick up a Basslite cheap on eBay, it will replace the original speaker. I think it's the best replacement option, considering performance, cost and availability. Going to 8 ohms also gives the option of an extension speaker, though I probably wouldn't do that.


For reference, cab volume is 1.857CF; the port is 16.8 wide x .75 high x 8.12 deep.

[tramp]

[ But I'll say this - I once gigged this amp outdoors without PA support (there was supposed to be), and it did OK. A little fartage, but not bad. Now, this was in a good ampitheatre with a low-volume jazz band, and I wasn't going for big low end. But the amp was pretty hot afterward, so I know I pushed it. .[/quote]

You are saying it got hot with the origional speaker?

[1n3]

Originally Posted by tramp

You are saying it got hot with the origional speaker?

Yes, it's always had the original speaker. At the end of the gig, I touched the control panel of the amp, and it was hot. I mention that only because it indicates that I had pushed the amp pretty hard; that gives some idea of what the speaker was getting. Obviously, EQ makes a big difference. I was probably cutting bass some, and boosting a little around 150hz.

If you boost bass and max out the amp, that's likely to give a bad result. But this little combo is hardly unique that way.

[tramp]

I sent a private message to 1n3 requesting info on the replacement speaker for the Bassman 150. I am posting the request and his reply so everyone will be able to read the info that was sent to me. Thanks 1n3

Did you happen to take any pictures when replacing the speaker? I never opened my up, is there any insulation in there already? What kind of insulation did you put in?

You said all the mounting holes lined up so everything was kind of simple - just unplug the old and plug in the new.

Is this speaker lighter than the one in there and does it make a difference in the sound? Whew - - that is a lot of questions.


His reply was:
I was hoping to reply where all - including future readers - could see it, which is why I asked you to repost these questions in your thread. But here is my reply anyway.


Quote:
Originally Posted by tramp
Did you happen to take any pictures when replacing the speaker? I never opened my up, is there any insulation in there already? What kind of insulation did you put in?

I didn't take any pictures, sorry. There was no insulation. I lined the interior with some foam mattress topper I had on hand. You can find it in any store that carries bedding. I cut pieces to size with a scissors, and attached the foam with construction adhesive (caulk gun).


Quote:
You said all the mounting holes lined up so everything was kind of simple - just unplug the old and plug in the new.

Is this speaker lighter than the one in there and does it make a difference in the sound? Whew - - that is a lot of questions.

To clarify: I have not replaced my speaker. It works fine, so there is no pressing need. I only said that if I can pick up a Basslite cheap, I will replace my stock speaker.

Mounting holes - I measured the hole spacing of my speaker, and compared it to the bolt circle diameter published in the Basslite brochure. They match. Surprisingly, these hole spacings vary quite a bit; many other Eminence 12s have a different bolt circle diameter, usually larger.

Weight - pretty close. The Basslite is probably a little lighter, having a neodymium magnet, but the stock speaker is fairly light because it's a cheap speaker with a small magnet.

Again -- thanks 1n3