Hello, Forum.
This topic has been inspired by J M Fahey, so, hopefully, he will chime in.
Because I sometimes modify small combos, I started wondering if anyone has ever tried any off-the-shelf midrange or woofer drivers in those. Such speakers can often be bought for peanuts (at least compared to speakers meant specifically for guitar) so they look pretty tempting. Do you have any experience with that?
Thanks in advance,
M.

Short answer, don't waste your time.
Hi Fi Drivers are high Compliance while MI Drivers are Low Compliance so they are worlds apart.
Hifi woofers rely on a defined space, a sealed box with or without a tuned port.
They will just wobble outside of a defined enclosure. They are mostly much lower on SPL levels. They give close to zero hi frequency while passing full range signal.

MI drivers can work in open or sealed boxes, I'm old enough to remember small pa speakers just mounted on a flat baffle board with no sides and a couple of angle brackets to hold them in a vertical position.

On the other hand keep your eye out for older hifi speaker boxes which used Low Compliance speakers as some will be able to reproduce a half decent sound for small guitar amps. don't expect them to handle hi power amps as they are very old and most will be low wattage.

Easy to see the difference as most hifi Woofers have a big rubber spider around the edge while low compliance driver will have the rippled spider often made of cloth or tarred paper.
Phil.

Thank you for your insight, Phil. That helps a lot.

Quote from: phatt on October 09, 2024, 12:42:24 AMOn the other hand keep your eye out for older hifi speaker boxes...

Any names / models worth considering?
M.

There would my 100's of obscure long forgotten brand names.
Forget the brand just get to know the difference between a Hifi woofer and a MI speaker.
If it has a foam rubber spider and it's easy to move the cone then don't bother.
If it has a rippled spider and the cone is stiff and harder to move the cone then it might be worth trying. In Australia Plessy/RCA and MSP speakers were used a lot in early hifi record players. but these are rare now and ones that do turn up the glue is way past the use by date and although they might work they will fail if driven hard by over enthusiastic bedroom thrashers with a 10 watt amp.
My rule of thumb for folks who are into speaker swaps "if the amplifier circuit is bright then use a darker speaker,,,If the amp tone is dark use a brighter speaker to balance the result.

I don't know what your aim is but there is a lot of talk on speakers making a huge difference and the market is full of fancy brand name speakers that claim to deliver tone heaven.
Yes true good speakers **CAN** make a big difference but it's not the whole story.
It's all about *Balance*
Each part of the amp circuit defines *the whole system tone* and it only takes one part to make or break that *Balance*.
You can destroy the *Tonal Balance* of a perfect Fender Twin Reverb Amp just by changing one 30Cent Capacitor.

If you are catching on the flip side of that is that sometimes just one Cap or Resistor swap in a circuit costing pennies can reap better results than expensive speaker swaps and a lot less work.
Of course this assumes you know what you are doing which requires some years of experience.
So for the novice swapping speakers is doable and the market gets flooded with fancy bright labels on the back of mass produced speakers that may or may not improve the sound. And so someone is making money from peoples lack of deeper understanding.
ps; I just realised that Mr Fahey has answered a lot of your Q's on another post,
 So yes take his advice.
I have personally learned a lot with His help.    
Phil.

Quote from: phatt on October 09, 2024, 07:37:47 AMI don't know what your aim is

I have nothing specific in mind, really. I'm just looking around for options. I sometimes happen to get my hands on a small, usually 8", practice amp and it seems that, usually, the weakest link in the signal chain there is the speaker, hence my interest in swapping.

Quoteps; I just realised that Mr Fahey has answered a lot of your Q's on another post,
 So yes take his advice.

Yeah, I saw that seconds after starting this thread
Thanks for any input nonetheless, Mr. Abbott

Quote from: Miyagi_83 on October 09, 2024, 02:15:30 PM

Quote from: phatt on October 09, 2024, 07:37:47 AMI don't know what your aim is

I have nothing specific in mind, really. I'm just looking around for options. I sometimes happen to get my hands on a small, usually 8", practice amp and it seems that, usually, the weakest link in the signal chain there is the speaker, hence my interest in swapping.

Yes speakers play a big roll, BUT these cheap little budget amps are made to a price point.
Zero R&D is done to make sure it produces a quality sound/tone.

I have 2 small amplifiers here, A Vox Pathfinder 10 and a Peavey MicroBass which claims 20 Watts at 4 Ohms, Which would be less than 20 Watt into 8 Ohm. (both use the same poweramp chip so a fair comparison)

The Vox is definitley a cheap crap toy while the Peavey delivers a quite usable sound for El guitar. They obviously spent time matching the circuit to the speaker when designing the Amp which delivers a smooth well balanced tone even though it only has a 5.5 inch speaker.

I also have a very cheap Casino 12 watt junk amp, delivers a brittle harsh trashy tone. So I trashed the small cab but kept the small chassis to see if I could improve the sound. Just by adding a low pass filter and fixing the design flaw in the tone control part it actually works well through a 12 inch guitar speaker. Most small guitar amps are trashy and brittle because they don't spend time rolling off the excess hifreq produced by small speakers and small cabs.

There are a few Utube vids of guys running the LM386 smokey amps driving into a Quad box.
they only produce around 1/2 to 1 watt. The quad box rolls off the top end.
While a smokey into a 3 inch speaker will have extreme hi freq = trashy tone.
If using small speakers you need to rethink design of the driving circuit.
Phil. 

Yeah, I also have a Vox Pathfinder 10 and while the cleans are fairly acceptable, the overdrive is just meh. Maybe it's just me, but I can't dial a usable OD tone on that. I haven't plugged it into quality speakers, though, because that amp has no speaker out jack, so for now it resides in my basement, waiting for me to get some time on my hands so that I can give it some love.

Now, my buddy's son's Kustom KGA-16 that I had in for repair yesterday is surprisingly usable, even through the small-fry speaker inside. Especially if you consider the price tag on that little sucker - they paid the equivalent of under 40 USD for it, including shipping, in early 2022. Used of course. Moreover, it does have an external speaker jack, so I ran it through a pair of 12" drivers and, honestly, I wouldn't be ashamed of using it live.

Johan Segeborn tests this all the time.
Here is one of his videos.

Sadly, it involves a cheap amp and a (relatively) expensive speaker.

Even so .....

Result is *incredible*