Ohms - do different ohm rated speakers sound different?

[tfarny]

This is a weird question, maybe - I'm curious though if say 8 ohm Celestion blues sound any different than 16 ohm - are the lower ohm ratings more efficient, or do they sound any different? Any reason to choose an 8 versus a 16 ohm speaker, if your amp has a selector?

 

[whyachi]

The main reason for different ohm options, I believe, is to help match them to solid state heads. T00b heads can usually work with anything, so it doesn't matter as much.

 

[Dan025]

well with solid state lower ohms will put out more power but not quite twice as much for halving the ohms. granted the head can only produce so much before something fails. the sensitivity tends to be about the same db at 1 watt at 1m but the amps and therefore the watts increase at the same volume setting. as far as tonality the motor structure will have different windings and maybe mass do to the different windings. i have never seen a comparison between speakers of the series and diameter with different ohm ratings. id really be interested if anyone has a more complete answer to this question.

 

[Death by Uberschall]

The main reason for different ohm options, I believe, is to help match them to solid state heads. T00b heads can usually work with anything, so it doesn't matter as much.

Reverse that.  :icon_thumright:

 

[jimh]

The main reason for different ohm options, I believe, is to help match them to solid state heads. T00b heads can usually work with anything, so it doesn't matter as much.

Reverse that.  :icon_thumright:

+1

 

[mayfly]

In my experience, there's no tone difference as long is the impedance is matched to the amp.

 

[-CB-]

are the lower ohm ratings more efficient

That, is a touchy subject.  Here's why...

The efficiency rating of a speaker is expressed as dB/1meter at 1watt at 1000Hz.

The efficiency is affected by the cone, the surround, the spider, the coil itself, the magnet structure and most importantly, the coil gap.  Celestion was noted for tight coil gaps, enabling very high efficiency.  As they say, "We put the loud in loudspeaker".  Very nice toned efficient speakers, until... they went overseas to produce them. 

There have been some stories of strangeness in the coil gaps on the imported Celestions (imported to the UK, slated for sales worldwide).  It very well may be that the 16 ohm speakers are more efficient.  They're not supposed to be.  They're supposed to control things on the winding of the coils to make them all fit the same gap, but this "ain't necessarily so".  What they generally do, is some math mumbo jumbo to use slightly smaller gauge wire, and different winding to make 2, 4, 8, and 16 ohm coils all work out to within very close to the same thickness.  Some are longer, some are shorter, but the thickness remains very close to the same.  This moves the actual efficiency up or down a bit on the frequency response (which also varies a bit, ahem....).

The whole thing is a huge can of worms if you want to get into it.  Recently dead Ted Weber went into this in a way that tried to spotlight some of the engineering that went into his speakers.  However, before that, back in the late 50's and early 60's the "HiFi" crowd was debating the same effect in their various Lansing speakers and their beloved Klipschorn's.

 

[Schlieren]

are the lower ohm ratings more efficient

That, is a touchy subject.  Here's why...

The efficiency rating of a speaker is expressed as dB/1meter at 1watt at 1000Hz.

The efficiency is affected by the cone, the surround, the spider, the coil itself, the magnet structure and most importantly, the coil gap.  Celestion was noted for tight coil gaps, enabling very high efficiency.  As they say, "We put the loud in loudspeaker".  Very nice toned efficient speakers, until... they went overseas to produce them.   

There have been some stories of strangeness in the coil gaps on the imported Celestions (imported to the UK, slated for sales worldwide).  It very well may be that the 16 ohm speakers are more efficient.  They're not supposed to be.  They're supposed to control things on the winding of the coils to make them all fit the same gap, but this "ain't necessarily so".  What they generally do, is some math mumbo jumbo to use slightly smaller gauge wire, and different winding to make 2, 4, 8, and 16 ohm coils all work out to within very close to the same thickness.  Some are longer, some are shorter, but the thickness remains very close to the same.  This moves the actual efficiency up or down a bit on the frequency response (which also varies a bit, ahem....).

The whole thing is a huge can of worms if you want to get into it.  Recently dead Ted Weber went into this in a way that tried to spotlight some of the engineering that went into his speakers.  However, before that, back in the late 50's and early 60's the "HiFi" crowd was debating the same effect in their various Lansing speakers and their beloved Klipschorn's.

 

[-CB-]

Sorry for the bloody eyes... maybe I should have added..... I dont think its of any consequence to guitar players with our typically non-linear and narrow bandwidth speakers.

Guitar speak's begin to lose it at 5k-6k range.  They have huge dips in the 1k-3k range, all depending on the magic factors mentioned above. 

Ever listen to a guitar played thru a HiFi amp with flat response?  It sounds terrible!  Our stuff is highly colored, and thats what we're used to hearing - thanks Leo....

 

[Death by Uberschall]

There is a belief that vintage Marshall's do respond to ohm loads.  It is believed that the best Marshall tones will be had with 16 ohm loads cabs. Supposedly has to do with the windings vs. iron content and inulation properties of the output trannys. SuperLizard can probably confirm this belief or add to it. 

Through my own experience, lower ohm loads (4 ohm) tightens up an amp slightly. Makes a real difference in my early Randall RG80es head (solid state) and makes the amp warmer with better bass responce. 

 

[OzziePete]

I used to help a few buddies around town lugging speaker boxes for them when they had bands in the pub rock era of the late 780s- early 80s here in Australia.

A lot of the guitarists had their (amp) heads tuned to the lightest number of ohms to get the aggressive tone out there... 4 and 8 ohms was the norm. With 4 ohms you really ran a risk with the dodgy wiring in some venues, but the guitarists wanted the amp to be on the verge of frying so they could use all the dynamics of the amp (?). Looking back on that I get the impression that no one had a clue what they were doing! I guess the boxes were either 8 ohms in parallel or 16 ohms. :dontknow: But there was certainly some serious growl in a lot of the Marshalls back then too.

 

[Schlieren]

Related question: the Musicman I use has a switch on the back for 4 ohm / 8 ohm.  Am I going to break the thing by using one or the other, or is that just for an auxiliary cab?

I have noticed that the 4 ohm side sounds a little bit beefier when I play through the thing... it's subtle but it's there

 

[Death by Uberschall]

Related question: the Musicman I use has a switch on the back for 4 ohm / 8 ohm.  Am I going to break the thing by using one or the other, or is that just for an auxiliary cab?

I have noticed that the 4 ohm side sounds a little bit beefier when I play through the thing... it's subtle but it's there

The switch needs to be set for the total ohms of the speakers, or the total ohm load. 8 ohm load = 8 ohm setting, 4 ohm load = 4 ohm setting.

Example: Two 8 ohm cabs = 4 ohms, so the switch should be set to 4 ohms.

 

[Schlieren]

How do I know which setting to use just for the combo amp itself?

 

[Death by Uberschall]

How do I know which setting to use just for the combo amp itself?

Use the ohm rating of the speaker/s. Think of each as a cab. One 8ohm speaker, set to 8 ohms. Two 8 ohm speakers, set to 4 ohms.