speaker impedence in pro sound situation

[daz]

What are the ramifications of putting a 4 ohm driver into a wedge monitor that originally had a 8 ohm driver?

[Leo_Gnardo]

Not much as long as the power amp can drive 4 ohms, rarely a problem. If your wedge is in parallel with others that are 8 or 16, the 4 ohm load will grab more current from the amp than 8 or 16. "Assuming" the speakers are the same otherwise as far as sensitivity, that current imbalance will have your 4 shouting louder than your 8. If it's all alone, no problem.

[Brad1]

What are the ramifications of putting a 4 ohm driver into a wedge monitor that originally had a 8 ohm driver?

Yep...the monitor, itself, doesn't care what you put in it...kind of. It's what all that monitor is connected to that are the main factors.

If you have only that one monitor, and the amp driving it can safely handle a 4-ohm load, then switching it out and running the 4-ohm one may give you a bit more power to that monitor.

The other "kind of" ramifications are the type of speaker being replaced compared to the original. If the original monitor was designed with a crossover to correctly blend the low and high frequency drivers, and you put a woofer in that has a different high-end curve, then it may not match well. It may overlap and create a low-mid "hump", or it may drop sooner and create a low-mid "hole". Kinda like you seriously boosted or attenuated that narrow range of frequencies with an equalizer.

Also, power handling should be considered. Are you replacing, say, a 200W max woofer with a 100W max, or vice-versa? That will make some difference in how the amp is run to either. Speaker efficiency wildly different? That'll make a difference.

If you end up using two different speakers from one monitor send, you'll also run into the problem of trying to get the best out of either, and having to compromise both so neither is run to its full capability. For instance, if you eq a monitor out to get good a good sound out of, say, a JBL...and it sounds perfect...and then you connect a Yamaha with different frequency response and power handling...the Yamaha will not be tweaked as well as it could. If you then try to tweak in the Yamaha...you've just UNtweaked the JBL. That was using two brands and models...but if you are changing drivers...you've just created pretty much the same difference.

If it's going to mismatch anything much...either the design of the monitor, the amp's impedance capabilities, other speakers connected in parallel, or fight with another speaker for frequency response...it's probably not worth it.

If you're using it by itself (or, doing a pair the same, etc.), the amp can handle it, it can handle the amp, and you can EQ it to work fine...no problem.

Brad1

[daz]

Got it, thanks guys.

[Enzo]

Also, if your cab has a crossover, that impedance change also changes the crossover frequency.

[soundguruman]

What are the ramifications of putting a 4 ohm driver into a wedge monitor that originally had a 8 ohm driver?

Draws twice as much current, and fries the horn easier. Horns are crossed at too low a frequency to start with, in many stock monitors. This encourages the horn to blow, and buying lots of diaphragms.(they do it on purpose, to get lots of money from you)
Better to change the frequency higher. Preserves the diaphragm, and sounds better, usually.
Like for example, many 12" speakers reach 2500 Hz with no problem, but factory crosses horn at 800-1K Hz. (to get your money)
Of course, an active crossover is way better than passive. You can set your horn at 2-3K, save diaphragms, and control the highs volume to balance with the lows. (most factory speakers are total overkill in the high frequencies)
Since it takes 6 speakers to equal the efficiency of one horn, you can see why the highs are overkill.
The active crossover allows balance of highs and lows, saves money on blown parts, and sounds way better.

[Leo_Gnardo]

Draws twice as much current, and fries the horn easier. Horns are crossed at too low a frequency to start with, in many stock monitors. This encourages the horn to blow, and buying lots of diaphragms.(they do it on purpose, to get lots of money from you)

I don't think I can agree with " 4 ohms woofer fries the horn easier" or "do it on purpose to get money" (IMHO they just try to flatten the curve where it would be wise to have a dip.) BUT . . . there IS a lot of wisdom in crossing the horn in at a higher frequency as SGM suggests. Yes it will send a lot less energy to the horn diaphragm making it less likely to blow. From my POV as a monitor mixer, how many times I've had to grab those graphic sliders at 800 to 3K and ditch 'em. So if you have a convenient "hole" in the response curve at the frequencies most likely to feed back, honk squeek & squeal, the less you have to panel-beat the response with your graphics. There's also the factor that the "beam" from the woofer gets nice and narrow at frequencies above 1K or so, and as long as the monitor is "aimed" right at the performer's ears, SGM's concept can be a genuine asset. How ya like that! Now I didn't invent this sort of concept but I DID pay attention to what excellent companies like UltraSound and Meyer were doing, and what I learned from Sound System Engineering by Don & Carolyn Davis (SynAudCon.) Also got some advice from top flite monitor mixers like Jimmy Ober (Clair Brothers) and Wevans (Chris Wade-Evans). Credit where credit is due.

But for now let's let daz get on with bolting his 4 ohm in and report back on what ya hear, OK daz?

There's an awful lot of budget monitors and even more x-pensive ones that have NO passive crossover to the woofer so it runs full range. Some smart PA outfits mount passive XO components even in the speakers that are used with active XO systems, just to steepen the XO curves and keep out-of-band energy out of the drivers. A coil in series with the woofer, a cap in series with the horn. Roslyn Sound (Long Island NY) had this and I thought it was brilliant.

FWIW I run my FOH PA mid-hi XO at 3 - 3.5K usually with 1" hi drivers, JBL 2420, that need some protection from getting fried. Use the horns to add some presence/air to the mix. The mids are JBL 120 so they have plenty of response to take up the slack in the 1K-3K region. Never popped a 1" diaphragm. Complain all you want purists . . . the crowd likes the sound and I even get COMPLIMENTS not complaints from club managers and owners. How often does that happen? Put that in your smipe and poke it.

[soundguruman]

I don't think I can agree with " 4 ohms woofer fries the horn easier" or "do it on purpose to get money" (IMHO they just try to flatten the curve where it would be wise to have a dip.) BUT . . . there IS a lot of wisdom in crossing the horn in at a higher frequency as SGM suggests. Yes it will send a lot less energy to the horn diaphragm making it less likely to blow. From my POV as a monitor mixer, how many times I've had to grab those graphic sliders at 800 to 3K and ditch 'em. So if you have a convenient "hole" in the response curve at the frequencies most likely to feed back, honk squeek & squeal, the less you have to panel-beat the response with your graphics. There's also the factor that the "beam" from the woofer gets nice and narrow at frequencies above 1K or so, and as long as the monitor is "aimed" right at the performer's ears, SGM's concept can be a genuine asset. How ya like that! Now I didn't invent this sort of concept but I DID pay attention to what excellent companies like UltraSound and Meyer were doing, and what I learned from Sound System Engineering by Don & Carolyn Davis (SynAudCon.) Also got some advice from top flite monitor mixers like Jimmy Ober (Clair Brothers) and Wevans (Chris Wade-Evans). Credit where credit is due.

But for now let's let daz get on with bolting his 4 ohm in and report back on what ya hear, OK daz?

There's an awful lot of budget monitors and even more x-pensive ones that have NO passive crossover to the woofer so it runs full range. Some smart PA outfits mount passive XO components even in the speakers that are used with active XO systems, just to steepen the XO curves and keep out-of-band energy out of the drivers. A coil in series with the woofer, a cap in series with the horn. Roslyn Sound (Long Island NY) had this and I thought it was brilliant.

FWIW I run my FOH PA mid-hi XO at 3 - 3.5K usually with 1" hi drivers, JBL 2420, that need some protection from getting fried. Use the horns to add some presence/air to the mix. The mids are JBL 120 so they have plenty of response to take up the slack in the 1K-3K region. Never popped a 1" diaphragm. Complain all you want purists . . . the crowd likes the sound and I even get COMPLIMENTS not complaints from club managers and owners. How often does that happen? Put that in your smipe and poke it.

It's a 4 ohm driver, NOT a 4 ohm woofer. Used in place of an 8 ohm driver.
And it DOES draw twice as much current. Try something called "ohms law."
Crossover freq too low: Yes, they certainly do it on purpose.
How do you think they make lots and lots of cash after they sell you the speakers? Diaphragms.
If you crossed the horn at 2-3 K instead of 800Hz, the diaphragm almost never blows. That's not part of the sales plan.
Sure, it makes the speaker really LOUD. But it also BLOWS your horns. AND each time it blows, it's another $110. What a money maker!
Personally, IMHO, anybody who crosses a horn (including 2 inch) at 800 Hz is a MORON. You can quote me on that.
"Never popped a 1" diaphragm?" They make SURE you do. That's the plan, Stan
Which is also why, 90% of the cabinets out there, sold in music stores, sound like a jet plane w/ asthma.
The highs rip your ears off...and there's no bass response to brag about.
That folks, IS the typical factory made speaker cabinet.
Electrovoice, Yorkville...they go to great lengths to protect the horn. And that's why I think those are the only two that are worth a crap.
JBL? Hahahahahahahahahaahhahahahhhhh!11!!!1111111 ILICISCCCAOMKB.

[Enzo]

A woofer IS a driver. Anything that pushes air is a driver. A woofer is not a compression driver bolted to a horn, but then that was not specified. A 4 ohm driver will try to draw twice the current of an 8 ohm driver is we are talking about the same driver. But if we are talking different impedance woofers be installed, they will have no effect on the horn driver.

Crossover freq too low: Yes, they certainly do it on purpose.

No, they most certainly do not. Other than the childish conspiratorial aspect, it is wrong on so many levels. If they did this, then ALL speakers would be blowing diaphragms all the time, and they don't. To purposely make speakers to blow diaphragms would very quickly get a speaker maker a reputation for unreliable speakers. A few extra diaphragm sales won't remotely make up for the lost equipment sales that result.

Personally, IMHO, anybody who crosses a horn (including 2 inch) at 800 Hz is a MORON. You can quote me on that.

OK, I will, here, let me quote you:

Personally, IM...a MORON.

[The Dude]

I haven't used any passive crossovers for a long time, especially given the availability of today's speaker processors with limiting, time alignment, eq, compression, etc. That said, I'm a bit out of touch regarding who's doing what with passive crossovers. So, I'm curious... Who in world is making speakers with a phenolic diaphragm crossed at 800Hz?

[soundguruman]

Ahhhhh? JBL?

[Leo_Gnardo]

Daz, can you set us straight? I think all but SGM have been assuming (and you know...) that it's the cone AKA woofer you're asking about. I can't say I've EVER run across a 4 ohm horn diaphragm but who knows, there's allsorts of things in this world.

SGM I think we're in agreement about MOST of this. And no harm in swapping out passive XO parts to raise the XO point to the horn as you describe & I expanded on. Same with setting active XO's.

The current JBL consumer MI product line - well I'm not too impressed and I gather you're not either. They USED to make some excellent products and it's those I'm most familiar with. FWIW I also like what EV's been making all along. In fact I swapped out the 12's in my JBL wedges for EV and that made for a more acceptable tone with less EQ faffing right away. Don't tell JBL.

I don't give a hang what "they" whoever they are, want. I modify my gear so it sounds good and just about bulletproof. And has proven to be, so far so good. And so can daz and just about anybody.

Jet plane with asthma, I like that description. No wonder so many musos have tinnitus.

I can just imagine the executive staff meetings at these sound gear outfits, a gang of Mr. Burns types gathered around the meeting table and signs on the wall: PLOT CONNIVE and SCHEME. Like the old IBM THINK sign. They're all rubbing their hands, dreaming of sacks of $100 bills and talking about how they're going to pick our pockets. I think you're jealous SGM, because you're not one of THEM. Wouldn't it be terrific if all you had to worry about was how big a yacht you're going to buy, and how to improve your golf score. Well you're NOT, so try to grab the correct end of the soldering iron and get back to work. Just like me and the rest of us.

SGM, dear heart, try not to have a wigout session on account of li'l ol' me. You're in upstate California. You KNOW what you should be doing - consuming the local cash crop. It usually settles people down. Hope it works for you.

Put "shaking head in bemusement" smiley thing here.

daz, you ask a simple question, get some good answers and then it devolves to another mud pie fight. Don't worry matey it's not your fault. Keep askin', we'll keep answerin'. Hope you can make progress with the good answers.

[km6xz]

I assumed LF driver also because cross over components would have to be larger needlessly and that i have never seen a 4 ohm HF driver.
My own preference is to not have hi-fi monitors with artists i worked with. The key information needed are pitch and timing so reducing full bandwith 'noise'(any data not increasing communications) just raises stage spl and lowers vocal quality. Even in-ear monitors are a problem when close miking. Wide band monitors degrade performance and is a bad habit

[Leo_Gnardo]

My own preference is to not have hi-fi monitors with artists i worked with. The key information needed are pitch and timing so reducing full bandwith 'noise'(any data not increasing communications) just raises stage spl and lowers vocal quality.

Agreed Stan! Old sound engineer adage: the wider you open the window, the more s#!t flies in.

And it's a hoot to see Rolling Stoves backline mic'd up with U87's & similar. What's the point? They STILL sound like an AM radio. SM57's would suffice perfectly well. The most successful garage band in the world. Don't get me wrong folks, I like the Stones. Just don't go to the show and expect hi fi. It ain't Pink Floyd.

[soundguruman]

Daz, can you set us straight? I think all but SGM have been assuming (and you know...) that it's the cone AKA woofer you're asking about. I can't say I've EVER run across a 4 ohm horn diaphragm but who knows, there's allsorts of things in this world.

SGM I think we're in agreement about MOST of this. And no harm in swapping out passive XO parts to raise the XO point to the horn as you describe & I expanded on. Same with setting active XO's.

The current JBL consumer MI product line - well I'm not too impressed and I gather you're not either. They USED to make some excellent products and it's those I'm most familiar with. FWIW I also like what EV's been making all along. In fact I swapped out the 12's in my JBL wedges for EV and that made for a more acceptable tone with less EQ faffing right away. Don't tell JBL.

I don't give a hang what "they" whoever they are, want. I modify my gear so it sounds good and just about bulletproof. And has proven to be, so far so good. And so can daz and just about anybody.

Jet plane with asthma, I like that description. No wonder so many musos have tinnitus.

I can just imagine the executive staff meetings at these sound gear outfits, a gang of Mr. Burns types gathered around the meeting table and signs on the wall: PLOT CONNIVE and SCHEME. Like the old IBM THINK sign. They're all rubbing their hands, dreaming of sacks of $100 bills and talking about how they're going to pick our pockets. I think you're jealous SGM, because you're not one of THEM. Wouldn't it be terrific if all you had to worry about was how big a yacht you're going to buy, and how to improve your golf score. Well you're NOT, so try to grab the correct end of the soldering iron and get back to work. Just like me and the rest of us.

SGM, dear heart, try not to have a wigout session on account of li'l ol' me. You're in upstate California. You KNOW what you should be doing - consuming the local cash crop. It usually settles people down. Hope it works for you.

Put "shaking head in bemusement" smiley thing here.

daz, you ask a simple question, get some good answers and then it devolves to another mud pie fight. Don't worry matey it's not your fault. Keep askin', we'll keep answerin'. Hope you can make progress with the good answers.

A. the higher the horn driver is crossed, the longer it will last and the less it will blow.

B. The higher the horn is crossed, the less it will move, and the less power it will require.

C. The higher it's crossed, the less distortion in the high frequencies. It sounds waaaaaaay better.

d. The easier it becomes to actually balance the highs and the lows. (flat response) Less feedback, less extreme EQ settings.

e. This is where most pre made cabinets fail miserably. The highs are 6X louder than the lows, and rip your ears. It's an on-going joke actually.

f. Electronic crossover is superior. Passive crossover is basically a joke. And, the joke's on you.

This is what speaker cabinet manufacturers don't want you to know. If you did this, they no longer will be selling you $$$ in replacement parts.
How long does it take the average user to learn this? Most of them never learn this. They just pay and pay and pay.

Sure, crossing lower is more "efficient." Sure it's louder, but sounds like garbage.
Stop being obsessed with "louder."
Start concentrating on clean clear sound, with highs and lows balanced flatter.

PHASE ALIGNMENT: gain 3db of loudness, without increasing the power, "at all."

That is correct, with phase alignment, the PA is twice as loud, with no increase in power.
You are losing the efficiency, to phase cancellation.
The difference is night and day. You would have to be deaf, to not notice the difference.

You will require an electronic crossover, with phase correction, to realize this difference.

JBL: I have no respect left for you. JBL is my "least preferred" speaker system.