Changing Ohm load without adding cabinets?

[Jack]

I also seem to recall that in general 12" speakers aren't inherently efficient.

Not sure why this would be the case. Some of the most efficient cabs around these days use 12" PA drivers. I'm thinking the Fearfuls and similar.

OP's cab on general should be reasonably efficient, 4 of any speaker will get somewhat loud. Obviously just not loud enough in this case.

 

[bdplaid]

Not sure why this would be the case. Some of the most efficient cabs around these days use 12" PA drivers. I'm thinking the Fearfuls and similar.

OP's cab on general should be reasonably efficient, 4 of any speaker will get somewhat loud. Obviously just not loud enough in this case.

Every spec I can recall for a 12 has the efficiency relatively low. The Avatar single 12 I had used the popular eminence Delta 12 LFA, a PA driver, which had 95 dB efficiency and needed gobs of power to get loud.
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[Wasnex]

Every spec I can recall for a 12 has the efficiency relatively low. The Avatar single 12 I had used the popular eminence Delta 12 LFA, a PA driver, which had 95 dB efficiency and needed gobs of power to get loud.

Genzler MG112T is rated 97dB at 8 ohms and MG212T is rated 100dB at 4 ohms (1w/1m).
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[Rune Bivrin]

Every spec I can recall for a 12 has the efficiency relatively low. The Avatar single 12 I had used the popular eminence Delta 12 LFA, a PA driver, which had 95 dB efficiency and needed gobs of power to get loud.

Well, the xxxLF models always have greater bass extension at the expense of lower efficiency. It's the same thing with the 15" models. The Delta 12A has 98.3 dB/1W, and if you look at the Neo drivers, the DeltaLite 2512II clocks in at 99.9. Or the KappaLite 3012HO, at 100.5. The voicing will be different, of course, but then again, the LF models are more aimed at subwoofer applications.
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[bdplaid]

If I were the OP I'd be looking for a cab with a lot more area and something above 100dB. I'm not at all a fan of single 12s, they just don't have enough cone area to move enough air. Especially in a rock band. Although, the no-longer-made Fender Rumble V3 112 did a good job; I had 2 and they were pretty good by themselves.

Honestly though, a 410 should get it done, he just needs the 4 ohm version of his cab. Or a new head. Being cash-strapped is a bitch, been there.

 

[Wasnex]

If I were the OP I'd be looking for a cab with a lot more area and something above 100dB. I'm not at all a fan of single 12s, they just don't have enough cone area to move enough air. Especially in a rock band. Although, the no-longer-made Fender Rumble V3 112 did a good job; I had 2 and they were pretty good by themselves.

Honestly though, a 410 should get it done, he just needs the 4 ohm version of his cab. Or a new head. Being cash-strapped is a bitch, been there.

I have an old GK 700RB/112 combo. I think the efficiency of the cab is probably around 95dB. The single 12 was not quite enough when the drummer started bashing. I could hear myself, but it didn't feel very satisfying to play. I had the impression I was pushing the driver into compression. I never got any distortion or fart outs, but the rig would just not go any louder.

For loud gigs I started adding an extension speaker with an EVM18B. The mixed speakers didn't sound great, but they gave me enough headroom to stick with the drummer.

I also toured with an Eden D210XLT run off one side of a QSC USA series power amp. I didn't have to deal with a basher drummer or need to push the room with this rig, so I stacked it on top of my rolling rack and tilted it back to aim it at my ears. The only times I typically had trouble hearing was in places with really bad acoustics...like gyms. Playing louder in bad acoustics usually just makes matters worse.

 

[Selios]

Spreading your cabinets on opposite sides of the stage won't help your problem; actually you'll end up with reduced bottom end. This is frequency dependent on the distance between the speakers.
It's better to couple them side by side or stacked.

Hi, citing my experience here was not about 2 cabs on either side of the stage. As per my space and weight limitations outlined in the OP, I am not interested in hauling two 4x10s around. My comment was only referencing that I had seen a major league bass player elevating his cabs recently, which was a solution suggested to me a couple times in this thread. I just figured that the TB crowd wouldn’t mind geeking out on the full description thank you and sorry for the confusion.

 

[H Nighttrain]

Wire two isolated speakon for 4-ohm each to the cab.
Run the pre-amp out from you head into a power amp
Run your amp into one 4-ohm speakon, and the power amp into another.
$150 and less than 7lbs, same tone.

Squeezing out every watt will not necessarily make you louder. YMMV

To the OP: my previous post in this thread echoes what seamonkey says. I should have added that it's probably not the right solution for you, although it's a relatively easy mod. I was just pointing it out as an option for anyone with a similar question as yours that might peruse this thread.

Your best option is, most likely, a more efficient cab with at least as much speaker area. Which, unfortunately, will require some cash outlay on your part.

FWIW, whenever I've gotten in a volume tussle with guitarists and or drummers (generally at blues jams), I've found the best solution is to turn down, way down (really just play lighter). A surprising number won't even notice (bedroom players), anyone else will get the message and accommodate . Just like any conversation - the first job is to listen, not talk.

 

[Ric Vice]

Glockenklang sells (or did sell) one as well.

I think they discontinued that standalone inpedance transformer. Plus it weighed quite a bit.

Here's a thought the Audiokinesis TC 112 (a stellar bass cabinet) switches between
8 or 4 ohm's. Besides the fact that it's a incredible bass cabinet with stellar frequency response and excellent sensitivity. I owned one of the earlier versions, they are outstanding.

 

[Downunderwonder]

I think they discontinued that standalone inpedance transformer. Plus it weighed quite a bit.

Here's a thought the Audiokinesis TC 112 (a stellar bass cabinet) switches between
8 or 4 ohm's. Besides the fact that it's a incredible bass cabinet with stellar frequency response and excellent sensitivity. I owned one of the earlier versions, they are outstanding.

View attachment 3464186 View attachment 3464188

What heck is the HF driver doing on the back?

 

[Jack]

What heck is the HF driver doing on the back?

I don't know about that particular cab (that may not even be a HF driver....) but there are cabs like that that are aimed at the double bass market, where gigs are often relatively quiet and one tiny cab is expected to be both stage monitor for the whole band and provide all the FOH volume for the audience. 360 dispersion helps.

I can think of a few cabs that have a tweeter pointing straight up, or something like the new EA cab that has opposite side-firing woofers and an angled up tweeter.

 

[Rune Bivrin]

What heck is the HF driver doing on the back?

The "4/8 ohm" switch works like this: The woofer starts out as a "high 4 ohms woofer" and the switch adds just enough series resistance so that the load the amplifier sees becomes, in effect, an "8 ohms nominal" load. The actual difference in impedance is much less than these numbers imply. When engaged, the switch reduces the efficiency by about 1 dB and reduces the voltage sensitivity by about 2 dB, but in turn you can safely parallel the cab with another 8 ohm cab for a loud gig.

The "Acoustic Friendly" option: Reduced-level rear-firing tweeter that adds a bit of top-end energy to the reverberant field and therefore comes a little bit closer to mimicking an actual acoustic instrument, and also lets anyone behind the cab (drummer perhaps) hear the overtones a bit better. More useful for upright bass than for electric bass.

So, essentially the 4/8 ohm switch is a resistor. There's no such thing as a free lunch.

 

[Ric Vice]

Just for clarification Acoustic Image builts the Double Shot with the two side firing 10"s. I had a chance to hear it at the ISB convention. Great cab for DB.

So, essentially the 4/8 ohm switch is a resistor. There's no such thing as a free lunch.

Very true, all I can say is that Duke builds exceptional cabinets and the sound wonderful. The Audiokinesis thread has lots of discussion and information about

his work.

 

[Jack]

...something like the new EA cab that has opposite side-firing woofers and an angled up tweeter.

Just for clarification Acoustic Image builts the Double Shot with the two side firing 10"s.

Well, them then.

 

[Ric Vice]

I don't know about that particular cab (that may not even be a HF driver....) but there are cabs like that that are aimed at the double bass market, where gigs are often relatively quiet and one tiny cab is expected to be both stage monitor for the whole band and provide all the FOH volume for the audience. 360 dispersion helps.

I can think of a few cabs that have a tweeter pointing straight up, or something like the new EA cab that has opposite side-firing woofers and an angled up tweeter.

Just for clarification Acoustic Image builts the Double Shot with the two side firing 10"s. I had a chance to hear it at the ISB convention. Great cab for DB.

 

[Wasnex]

So, essentially the 4/8 ohm switch is a resistor. There's no such thing as a free lunch.

FYI, Epifani's DIST line uses dual voice coil drivers to change impedance.

 

[Passinwind]

What heck is the HF driver doing on the back?

Changing the ratio of direct to reflected sound in the high frequencies. In some ways it's meant to emulate the back wave from the body of acoustic instruments. Duke's inspiration came at least partially from hearing my EUB at the first TB GTG he attended.

 

[Ric Vice]

Changing the ratio of direct to reflected sound in the high frequencies. In some ways it's meant to emulate the back wave from the body of acoustic instruments. Duke inspiration came at least partially from hearing my EUB at the first TB GTG he attended.

Charlie,

Thank you so much, for coming on and adding your always thoughtful posts. They're much appreciated.

 

[Ric Vice]

Well, them then.

Here's a picture, they are 4 ohm