How does speaker ohm effect sound, if at all?

[BlueJakester]

I'm wondering if there is any difference in sound or performance to be realized by different speaker ohms?

Example; if I had two identical 1x12 cabs loaded with Celestion G12H30 speakers, but one speaker being 8 ohm and the other 16 ohm, would there be a potential difference in sound/performance?

I realize there are many variables, like amp, guitar, volume, etc., however my question stems more from a theory point of view.

Thanks,
Jake

[Alexo]

I don't know about the speaker end, but on the amp end, I have heard tell of 16 ohm impedance taps sounding much better than 4 or 8 ohm taps. This may be due to the 16 ohm tap running the entire "length" of the output transformer, or the tap's relation to where negative feedback is taken off of the transformer...

[BBQLS1]

I don't know about the speaker end, but on the amp end, I have heard tell of 16 ohm impedance taps sounding much better than 4 or 8 ohm taps. This may be due to the 16 ohm tap running the entire "length" of the output transformer, or the tap's relation to where negative feedback is taken off of the transformer...

Then how come a Super Reverb (2 Ohms/4 10" in parallel I think) sounds so good?

[Alexo]

I didn't say it wouldn't! This is not my personal experience, like I say, I'm just saying what I read...

But... that's not a multi-tap OT in the super, the 2 ohm tap could be running the entire "length" of the OT, if that even affects the sound. I should have said in a multi-tap OT, some folks say that the higher impoedance tap sounds the best.

[Merlinb]

AFAIC that whole "using the whole length of the winding" thing is just an old wives tale. The only advantage to it is that you get marginally better coupling (read: not noticeable in a lofi guitar amp) and less magnetic leakage.
The only real difference is that a 16ohm speaker will usually be more sensitive for a given source impedance, so it may seem a notch louder, and maybe get less damping (= less speaker compression). Of course, we could be talking a couple of dB's which would be negligeable at best.

[rjgtr]

Actually I think using higher impedences is generally safer. Here's why. The wire you connect the speaker with has resistance. The lower the ohmage, the more this wire can affect the sound, by adding resistance. A 2 ohm load is easier to effect than a 16 ohm load.

As for practical considerations, think about this. Most combos run at eight ohms. A Marshall stack (2 cabs) runs at 8 ohms. An amp running at 8 ohms is the sound you've heard on records most often. This is not the full winding of the OT in the case of a stack. So I don't think it makes a ton of difference, even if you can hear it in a totally quiet listening environment.

Of course a Fender Champ is only 4 ohms and that worked well on Layla!

[tarzanalog]

Actually I think using higher impedences is generally safer. Here's why. The wire you connect the speaker with has resistance. The lower the ohmage, the more this wire can affect the sound, by adding resistance. A 2 ohm load is easier to effect than a 16 ohm load.

OK, then... what's the best wire to use if you're building your own cab?

[SpentMusic]

Given that most components in an amplifier are + or - 5/10/20/30 percent and this goes for most audio hifi as well. Get a tried and true self builders speaker wire. The old #14 or 16 brown lamp cord.

You will get some people that say it is the worst and some say it is the best. Like everything in the music world it is what you hear. I have used it for years when on the road to build my own speaker cabinets for guitar and PA equipment. I don't now for one reason only. It is a point in the selling process that you have to defend to someone. So I buy spools of black and white speaker wire and twist them myself.

JMO and what my ears hear.

[rjgtr]

Jeff is right.

The only thing that seems to matter in speaker wire is the guage. Just make sure it is big enough wire.

Case in point - a well known Hi end audio magazine did a test where they did a blind test. One otherwise identical setup used a "high end" monsterish speaker cable and the other used common household wire (Romex). They could neither measure nor hear a difference.

Zip chord works great. In an amp, speaker cabinet or combo, there's no need for the heavily jacketted wire either. Just normally insulated wire is fine.

[jaysg]

Sorry if this seems like a hijack...about the Canadian Marshalls which weren't allowed to use the 16 ohm tap -- was the issue there that the OT primary voltage swing in cranked EL-34's exceeds one of the internal breakdown voltages...or was it that the actual OT primary insulation wasn't rated high enough?

[herby2]

There is also some consideration re using different taps on output tranny to get better sound . Generally speaking a 16 ohm tap will give you better sound as it comes from having more winding on the transformer than say a 4 ohm.

As for wire the least resistance the better but generally the fatter the wire the better. Electric multi-stranded copper is good (2.5mm). Silver is the best...but not available and would be expensive.

Speaker cables are low impedance so the effect of noise isn't an issue.

So save your pennies or cents

[Merlinb]

There is also some consideration re using different taps on output tranny to get better sound . Generally speaking a 16 ohm tap will give you better sound as it comes from having more winding on the transformer than say a 4 ohm.

We've been through this and the evidence is circumstantial at best...

[zaphod_phil]

And who is to say which is the "better" sound anyway?

There are so many other factors that also need to be taken into account, including the amp's overall tone, the type of speakers and cab being used, and so on. So different OT tappings may suit different amps better, as well as players' own personal tastes.....

[rjgtr]

More wire around the core should equal more bass all other things being equal. It is easier to reproduce bass in a large room than a small room because the soundwave has enough space to develop. Why wouldn't a transformer work in a similar fashion. A P-90 has more low end than a Fender single coil, but it also has more wire.

But Phil is right, more bass response doesn't always equal better tone. So maybe running an SLP on 8 ohms is more satisfying than running it on 16 ohms. (Yes, I know it would have to be since running at 8ohms means you're running two 4x12s! ). In fact, one could argue that a Marshall 100 watt amp is designed to run at 8 ohms and that running one at 16 ohms isn't the right sound anyway.

At the end of the day the theory is great, but even better is getting the tone you want.

[KHStudio]

How many ohms were the speakers in the ORIGINAL 18 WATT AMPs???

Parallel or series???

What was the load - 8 or 16 ohms???


Kevin

[argus]

Quick question and comment.

What if you plug a 16 ohm speaker into a jack that says 8 ohm only? Problem or no?

I am aware that using a 4 ohm speaker into a 8 ohm output jack is a real problem, but what about going higher impedence with the speaker? Problems?




OK, Comment:
As for wire, I won't try to change anyone's mind here, and I don't know thing one about building amps (part of why I am here), but I have done blind tests a number of times. Sliver wire is brighter than copper, better in some applications, not in others. The "zero crystal" wire are better, absolutely. If it is worth the cost, that is of course for each person to decide for themselves. As for the jacket, everytime someone buys another cell phone, they are throwing more and more pollution into the air. While dielectrics mattered very little in the fifties, it does matter now, at least if you live in a Metro area. Notice any difference in the range of your remote car car locking device in rural versus metro ares? I certainly do.

I believe most everyone agrees starving your amp of wall power is very hard on it. I always use huge gauge (detachable) wire for the AC.

Hope I haven't ticked anyone off so much they won't answer my earlier question. Thanks.

[rjgtr]

What if you plug a 16 ohm speaker into a jack that says 8 ohm only? Problem or no?

I am aware that using a 4 ohm speaker into a 8 ohm output jack is a real problem, but what about going higher impedence with the speaker? Problems?

You are presenting the wrong load. While some people feel using the higher impedance is safe, the answer is it depends. Does the OT have the extra headroom to tollerate a mismatch. Some do and others don't. Are you running the amp full out, or at lower settings? Are you using a highly distorted signal (closer to a square wave)?

It will also effect the output power available.

Having said all that I had a Blackface Princeton I ran with such a mismatch and it made the amp a little darker and ran fine.

[Alexo]

I believe most everyone agrees starving your amp of wall power is very hard on it. I always use huge gauge (detachable) wire for the AC.

Not to argue, but I used to think a super heavy-duty power cord would be an improvement. Then I started building amps. The leads that come off a power transformer are not any heavier duty than regular zip cord, nor are any of the internal wires, really. Any system is only as strong as its weakest point, so an extra heavy-duty wire feeding a medium gauge wire is a waste of money, IMO. Besides, some people deliberately starve the power on their amps. In the hi-fi world, the better the quality, the better the sound, but not so much in guitar amps, in my experience.

[zaphod_phil]

I believe most everyone agrees starving your amp of wall power is very hard on it. I always use huge gauge (detachable) wire for the AC.

There is no way under the sun a regular mains cable is going to "starve" any guitar amp of wall power. Just work out or measure the resistance of a reular IEC cable and you'll see why. The only way your amp can get starved of power is if the filter caps (aka reservoircaps) are too small. But a lot of folks actually like that in guitar amps, because the starvation manifests itself as sag.

[zaphod_phil]

...I have done blind tests a number of times. Sliver wire is brighter than copper, better in some applications, not in others. The "zero crystal" wire are better, absolutely.

If you can hear that difference (and I'm not disputing it at all) then you must be able to hear frequencies around and above 15kHz. Have you ever thought of getting someone to measure the frequency response of your ears, using a good hifi rig and a signal generator? It would be neat to find out how high your hearing goes. You may find out that you're a very special person, apart from anything Barney the Dinosaur may have to say on the subject.

Now, on the subject of guitar amps, it's usually considered preferable to roll off frequencies above 5KHz, as they tend to make the tone sound harsh and fizzy.

I believe most everyone agrees starving your amp of wall power is very hard on it. I always use huge gauge (detachable) wire for the AC.

There is no way under the sun a regular mains cable is going to "starve" any guitar amp of wall power. Just work out or measure the resistance of a reular IEC cable and you'll see why. The only way your amp can get starved of power is if the filter caps (aka reservoircaps) are too small. But a lot of folks actually like that in guitar amps, because the starvation manifests itself as sag.

In the hi-fi world, the better the quality, the better the sound, but not so much in guitar amps, in my experience.

Actually with guitar amps you often have to do the opposite of what you would do in hi-fi. In hi-fi terms a lot of guitar amp designs are really awful! I had to go and unlearn a whole bunch of my audio electronics theory when I got into guitar amps.