Replacement Speaker [newbie advice please)

[Geospectrum]

I was in the market for a small, portable amp for jazz. I settled on a TC Electronics BAM20 after seeing a YouTube video. The cab I am using is an old Fender Frontman with the amp removed. To my surprise the combination sounded very nice. Clean and warm, loverly for my archtop. Even more surprising is the volume, I expected the amp to drive the speaker almost to destruction as the BAM20 is rated at 200w at 8 Ohm and the speaker in the cab is just a cheap 8ohm 15w Fender. I was able to ( and had to) turn the amp up to get the volume I needed.

My question really is I’d like to replace the speaker on the assumption that a better speaker will sound better. The one I have in mind is the 8inch Celestion FT8018. Which is rated at 100W at 8 Ohms. Will this be louder as well?

[rpjazzguitar]

"clean, warm, loverly ... ", loud enough and cheap ...

That's going to be hard to improve on.

[burchyk]

Eminence Beta is the speaker used in Mambo amps and is what I'd recommend.

[Gitterbug]

Loudness depends on two factors, input wattage and speaker sensitivity. I assume you mean Celestion TF0818, which has a sensitivity of 94 dB. Your stock speaker can hardly exceed this by a significant amount. The BAM200 is the least loud of the 200W bass micro-amps, suggesting its wattage has been stated optimistically. I think you'll be safe with the TF0818 on higher volumes, perhaps not quite to the hilt. Most amps begin to break close to peak power; BAM stays clean longer than most. I've called it Polytone Replacement Therapy, with some reason.

[Herbie]

Eminence Beta is the speaker used in Mambo amps and is what I'd recommend.

I use Beta 8A too with my Quilter TB202 combo. The sound is perfect.

[Gitterbug]

If weight matters, the Beta 8A's is 6.6 lb vs Celestion's 5.1 lb.

[Tom Wright]

If you have to turn way up the issue might be low output of the guitar. Gain is not identical to power, my Trace Elliot Elf has huge gain, meaning I don't turn the knobs far. My GK MB200 is low gain, apparently expecting high-output active bass guitars, even has a 15 db pad. The gain on most amps is dependent on tone settings, as in when they are all dialed back gain will be low.

I like the Eminence 8" woofers, smooth frequency response and will take plenty of power. Speakers don't blow like in the old days. A rating just means it won't clip until the rated power is exceeded.

[BBGuitar]

Don't overthink it buy the highest wattage you can afford. You might want to add a tweeter.

I don't use this one now that I got a Fishman LoudBox mini. It was a Sidekick Bass 65, new box with 12-inch speaker and horn piezo tweeter. The chassis was cut down to its smallest size. No attention was paid to acoustic speaker design. I think it sounds great.

[nevershouldhavesoldit]

I think the main quest is not for a louder box but for better sound quality. Loudness seems to be a secondary issue, as stated:

I’d like to replace the speaker on the assumption that a better speaker will sound better.......... Will this be louder as well?

Whether a replacement speaker will sound "better" is a whole 'nuther matter. Most standard production Fender amps from the last 2+ decades have had "Fender Special Design" speakers made by Jensen. They're decent speakers with (as Gitterbug points out) decent sensitivity of about 94 dB for a 1W, 1 kHz input signal at 1 meter away. They sound OK to my ears - you get at least as much as you pay for, and probably even a little bit more. I assume the OP's amp is a Frontman 20, as that's the only one I remember to have an 8" speaker in it. There are a few 8" drivers with sensitivity of 96 or slightly better, but this is only a 2 dB increase in SPL at 1 meter - it's not going to be a revelation.

But the OP says the amplifier was "removed". As I recall, the Frontman has a simple partial chassis that is wide open into the speaker cavity. So if the amp chassis is removed, there's a large rectangular opening into the speaker cavity where the amp faceplate used to be. This is much too large to be an effective tuned port or vent. It almost certainly degrades frequency response linearity and has a negative affect on the sound. Changing the speaker may affect this to some degree, but it's impossible to know if it will be any better (or any worse) except by trying it. I strongly doubt that any speaker would sound significantly better than the stock one.

As the cabinet and the speaker chosen for it were designed to work best together with the top front opening filled by the amp's face, I suspect that filling that opening (assuming the amplifier was actually removed, as stated) would improve sound quality a lot more than changing the speaker. The easiest way to do that is to simply replace the chassis in the cabinet but not connect it. Add a 1/4" jack to the back panel for direct connnection of the BAM 200 and it's ready to go.

If the chassis is still in place, changing to a different 8" speaker might please some of us more than the stock one. There are very nice 8" drivers from Weber, Jensen, Celestion, Eminence, Mojotone, and Warehouse Speakers. I'd read up on each one and try the one that the manufacturer and reviewers describe in terms that appeal to you (e.g. warm, bright, mellow, etc). There's no way to hear them all in a specific cabinet, so it's pure trial and error. Fortunately "like new" speakers that only cost $60 or so new are easy to resell. Unfortunately, they sell used for half to 2/3 of the original price - and you have to ship them unless you find a local buyer.

So trying to find a speaker that sounds "better" in a cabinet like this is likely to be expensive relative to the value of the amp. Given that a geat sounding new amp like a Champ 20 can be had for about $110 delivered, I wouldn't put out even $50 in search of better sound from an old Frontman cabinet.

For better sound from the BAM, I’d look for a well designed 8” cabinet. Vox makes a really nice one (the BC108) that’s widely available used for well under $100. The stock speaker is pretty good - I had one for a few years that’s now in the hands of another happy forum member. I gambled on improvement from a Celestion speaker, but it wasn’t significantly better than the one that came in it.

[KirkP]

I’ve tried several 8” drivers in a small ported cabinet and my favorite was the Eminence Beta-8A.
https://eminence.com/products/beta_8a

I haven’t used the TF0818, but the frequency response curve suggests it will have less bass and maybe a bit more treble.
Celestion TF0818 - Pressed Chassis Low Frequency Driver

Edit: I also have an Celestion TN0820, which is similar to the TF0818 except with a neo magnet to reduce weight. But its frequency response curve suggests it has more bass than the TF0818.

[KirkP]

I was able to ( and had to) turn the amp up to get the volume I needed.

I don’t understand why needing to turn the amp up is a problem. Do you mean the gain and master volume are maxed out and it’s still not loud enough? Are you having problems with noise or distortion from the amp? I doubt speakers with higher power ratings would be more sensitive than your 15 watt speaker. But they will obviously be able to produce much more volume while staying clean.

[Woody Sound]

FWIW, I believe Quilter used the Celestion in the 8" MicroPro series.