Replacing an 8-ohm spkr. with a 4-ohm skpr.?

[johnhenry]

Is it possible to replace an 8-ohm bass speaker with a 4-ohm in the same cabinet. It's a 15" Bag End bass cabinet? It's not a D series speaker/cabinet.
I've asked Bag End and they're very good at responding. I thought of asking TalkBass too. Maybe someone out there has done this and could tell me about the results. Thanks to all!

 

[Stumbo]

What head are you running?

If you use the same type speaker except 4 ohms you should be fine as long as you're not running another 4 ohm cab( unless your amp can handle 2 ohms).

Cabs are usually made for specific speakers. What speaker does Bag End recommend?

 

[2saddleslab]

I switched from 8ohm to 4ohm to get the most watts out of my amp. Very happy with the results.

 

[Old Garage-Bander]

I switched from 8ohm to 4ohm to get the most watts out of my amp. Very happy with the results.

Two similar 8 ohm cabs will get you louder that one four ohm cab.
The increase in loudness using watts is not nearly as much as the increase in loudness by moving more air.
That being said, in some cases folks want to get all they can out of their amp without having to lug an extra cab around.
And if that setup is loud enough to do the job then all is well.
It really boils down to ones personal preference. Hopefully there is a suitable 4 ohm replacement that works well in the cab designed for the original 8 ohm speaker.

 

[BassmanPaul]

I switched from 8ohm to 4ohm to get the most watts out of my amp. Very happy with the results.

I’m glad you are happy with the result. Doing what you did is a crapshoot at best unless you ran the numbers first. You’ll also find that your cabinet is almost unnoticeably louder. You’d need to increase power ten times to get twice as loud.

 

[GtenderG]

I rehabbed an old Kustom tuck and roll 2x15. I replaced the 2 16ohm speakers with 2 8ohm Eminence speakers. Knocking it down from 8ohm to 4ohm. I didn't do any calculations and luckily I got a cab that was tight and punchy. Its still heavy but its probably about 10 pounds less. Louder by only a bit. It doesn't get much use. Hopefully, I'll do some gigs that will require a big cab. .

 

[kpc]

I rehabbed an old Kustom tuck and roll 2x15. I replaced the 2 16ohm speakers with 2 8ohm Eminence speakers. Knocking it down from 8ohm to 4ohm. I didn't do any calculations and luckily I got a cab that was tight and punchy. Its still heavy but its probably about 10 pounds less. Louder by only a bit. It doesn't get much use. Hopefully, I'll do some gigs that will require a big cab. .

I don't think you'll hear much difference in volume aside from the fact that the cab is tuned to that speaker.

 

[2saddleslab]

I’m glad you are happy with the result. Doing what you did is a crapshoot at best unless you ran the numbers first. You’ll also find that your cabinet is almost unnoticeably louder. You’d need to increase power ten times to get twice as loud.

It was a crapshoot, something I didn't realize at the time. But the original speaker was blown, I had no choice but find a replacement. The cab is much more powerful going from a 8ohm stamped frame speaker at 350 watts to a 4ohm caste frame Black Widow at 700 watts [now 800 w/ my new PF800]. Now the cab can handle what's thrown at it and delivers chest pounding lows. The original speaker sounded like the campfire scene in Blazing Saddles.

 

[JimmyM]

It was a crapshoot, something I didn't realize at the time. But the original speaker was blown, I had no choice but find a replacement. The cab is much more powerful going from a 8ohm stamped frame speaker at 350 watts to a 4ohm caste frame Black Widow at 700 watts [now 800 w/ my new PF800]. Now the cab can handle what's thrown at it and delivers chest pounding lows. The original speaker sounded like the campfire scene in Blazing Saddles.

The speaker determines how much wattage it handles itself, not the head, although I must say I like your choice in heads And the frame has nothing to do with how much it handles.

 

[2saddleslab]

Two similar 8 ohm cabs will get you louder that one four ohm cab.
The increase in loudness using watts is not nearly as much as the increase in loudness by moving more air.
That being said, in some cases folks want to get all they can out of their amp without having to lug an extra cab around.
And if that setup is loud enough to do the job then all is well.
It really boils down to ones personal preference. Hopefully there is a suitable 4 ohm replacement that works well in the cab designed for the original 8 ohm speaker.

I'll admit to falling backwards into a bucket of you know what and looking good doing it. Over 30 years playing professionally I've lived & learned the whole watts vs volume vs number of drivers thing. This cab works perfectly for small quiet rooms to boisterous downtown bars.

If you think that's a roll of the dice, I have a blonde Fender 2x12 sporting EV Pros that, coupled with a GK 1001RBII, will leave bruises.

 

[2saddleslab]

The speaker determines how much wattage it handles itself, not the head, although I must say I like your choice in heads And the frame has nothing to do with how much it handles.

Then lets call it pure dumb luck. Been lucky all my life.

 

[JimmyM]

Then lets call it pure dumb luck. Been lucky all my life.

Well at least you know that just because the knobs go to 10, you don't have to run them that way

 

[MrCash]

I’m glad you are happy with the result. Doing what you did is a crapshoot at best unless you ran the numbers first. You’ll also find that your cabinet is almost unnoticeably louder. You’d need to increase power ten times to get twice as loud.

I do agree with you. If you were putting in any different driver you must really model it.

But I think if you replace a like for like driver bar an ohm difference you are likely to get an ok result. After all many companies offer cabs with 8 and 4 ohm choices and the cabs are exactly the same.
That result though as you say will be very minimal from going 8 to 4 ohms. And there is probably some placebo effect too haha. But that might be enough for some.

 

[Kirk Bryant]

Not to be Captain Obvious or anything but will BE sell you a 4 ohm version of the same speaker?

 

[DavC]

it's limiting when you want to ad another cab ...

if you'll use just 1 cab 100% of the time , forever ... then i wouldn't think it would matter

 

[BogeyBass]

You can put a 4ohm driver in there.

Just really isn't that many 4 ohm drivers

Usually the 4ohm versions have less efficiency. So the extra power will make up for it...but you get to the same SPL
And just make the amp hotter.

And no you don't have to model it lol

 

[BadExample]

+ about 3db if the replacement is the same excepting ohmerageness. Can the 4 ohm handle about double the wattages and more mechanical stress? If you can make it fart now, I think not much point in an otherwise identical speaker.

The pitfalls of a "better" or upgrade speaker have been covered above, but if the BE happens to be a sealed cab, ill effects of guessing are minimized compared to ported. Of course you can just not guess by modeling, or for sealed see if they offer a cab volume spec like eminence does. Shooting for a sealed cab speaker the requires a volume that your cab matches near the middle of the range should be a good compromise of spl and cone control/antiflatuance. It seams to me that volume for a particular speaker tends to be about half the cab size winisd will suggest if you enter the TSPs and let the software determine the cab volume. Essentially, ignoring tone goals, larger = more spl and smaller = more cone control. Smaller cuts spl, but gets a cleaner bass sound and safer as far as mechanical limits.

Edit: spel checkerized it.

 

[TheRealKong]

I once was lucky, when I swapped woofers in a SWR 212" (ferrit, 8 Ohm) to neo woofers with a total impedance of 4 Ohm. The cab sounds great, but it didn't get any louder, lets say, its not hearable. But I was able to use the cab with some all-tube - heads that don't accept 8 Ohm.

This time I bought a BenzBenz NeoX T 212 (4 Ohm), and it seems like the former owner did stress the cab too much. In some setings you hear the cab overexcursing - at living room levels. So I asked agedhorse, but there are neither reconing kit nor two replacement speakers available. I found some speakers that should do it, but they will reduce the impedance to 8 Ohm (2 x 16 Ohm). Agedhorse recommendet not to go that way, but rather take two woofers from the same manufacturer GenzBenz used, but not the OEM version GenzBenz mounted. Because they are no longer available. I will take the stock models because the difference is not that significant, the OEM - modell just had a different mid voicing. This is what EQ are for.

I would mount the given speaker into the cab whatever BagEnd recommends. They maybe used OEM - speakers with a different voicing and know best, what suits the cab.

Otherwise changing a cab to 4 Ohm does limmit the number of cabs you are able to use. Remember, you should not go under the given impedance of the amp. So when your amp says "minimum 4 Ohm", you don't want to let it drive two cabs with less than 8 Ohm.

Next point: 8 - Ohm -cabs are better controled by the amp. The cones get damped better, this helps for a better articulated, punchy sound.

 

[jsbarber]

When I sent my portaflex to Jess Oliver to replace a transformer, he changed the voice coil from 8 ohms to 4 ohms keeping the same driver. I don't know if this is an option with your driver, but it might work better than replacing the driver. It would likely be less expensive as well.

 

[BassmanPaul]

Then lets call it pure dumb luck. Been lucky all my life.

I’ve always liked it when I get lucky!