are 15 watts and 40 watts the same volume

ChrisMusic

I am right up there with @ThePrettyDamned with the stereo stuff, also ambience and chorus would sound great, & positioning different guitar sounds in the mix.

Anything that adds spatial field movement to the dynamics is interesting in my book.

On the subject of speakers, I assume that the SPL is proportionate to the surface area of the cone available to pump air, the sensitivity of the speaker (efficiency), and the power applied from the amp (driving force).

What are the compromises over speaker sensitivity?   - frequency response, "tone" etc

How much influence does guitar cabinet design have?

What about multiple drivers, either in one or multiple cabs, together or separated as in stereo etc?

What about projection, directionality and "authority / grunt" ?

What else should be taken into consideration?

ICBM

ThePrettyDamned said:

This is interesting. It makes me wonder whether a pair of slightly smaller (and therefore portable) amps with a stereo delay pedal to get both running at once would make for a reasonable gigging option, as well as giving you awesome ping pong delay sounds.

Obviously it wouldn't be for everyone, but the idea of a pair of 1x10 combos with 15 watts is easier to carry from the car to the pub than a single 50 watt head and 2x12. Might not give the sound you want but for poppy stuff, blues, and anything that would usually use a slightly pushed power section, it'd be easier than carrying an ac30.

I did exactly that for several years with two Fender Super Champs in stereo. It worked very well for a light acoustic-electric pop band, although when I moved to a darker alt-rock kind of band it didn't.

ChrisMusic said:

On the subject of speakers, I assume that the SPL is proportionate to the surface area of the cone available to pump air, the sensitivity of the speaker (efficiency), and the power applied from the amp (driving force).

What are the compromises over speaker sensitivity?   - frequency response, "tone" etc

How much influence does guitar cabinet design have?

What about multiple drivers, either in one or multiple cabs, together or separated as in stereo etc?

What about projection, directionality and "authority / grunt" ?

What else should be taken into consideration?

The sensitivity figures already take the cone area into account - that's why (all other construction factors being roughly equal) a typical 12" speaker is about 2dB louder than a typical 10". So really most of what you need to know for final volume is the sensitivity and the power input.

But (of course! ) it's not as simple as that because speakers don't respond exactly linearly... in fact they become less efficient the harder they're driven, which is one of the reasons that increasing the number of speakers increases the volume - because with the same power input divided between more speakers, each speaker is then operating in a more efficient part of its range. It's especially true when you're comparing speakers driven into 'thermal compression' near their maximum power rating to ones that aren't.

(In theory, if speakers were perfectly linear then increasing the number of speakers would make no difference because the same power would simply be divided among more drivers of exactly the same efficiency.)

The sensitivity doesn't take voicing into account either, which can make a big difference to the perceived volume since your ears aren't linear either - a speaker which has a peak in the upper mids will sound louder than one with a peak in the lower mids even if they measure the same on average, because your ear is more sensitive to upper mids.

Cabinet design and the way multiple drivers interact also makes quite a big difference, to the directionality in particular, which can increase or decrease the effect depending on where you're standing. Slightly counterintuitively, the more drivers you have in an array (if they're facing the same way), the more directional it is, not less - and most so in the same direction as the spread of the speakers. So actually a traditional horizontal 2x12" should be more directional across a room than a vertical one.

Most guitar cabinets are not well-designed acoustically though - or really designed at all, other than being a box about the right size. They're usually not tuned, and if they sound good it's more the result of trial and error than science. The cabinet material also makes a noticeable difference, whereas with 'proper' (hi-fi, PA etc) cabs, a lot of effort is used to eliminate cabinet resonance so it tends not to.

So it's a bit like amplifier power really… you have to try it to be sure, although the figures do give you a rough guide.

Barney

ThePrettyDamned said:

This is interesting. It makes me wonder whether a pair of slightly smaller (and therefore portable) amps with a stereo delay pedal to get both running at once would make for a reasonable gigging option, as well as giving you awesome ping pong delay sounds.

Obviously it wouldn't be for everyone, but the idea of a pair of 1x10 combos with 15 watts is easier to carry from the car to the pub than a single 50 watt head and 2x12. Might not give the sound you want but for poppy stuff, blues, and anything that would usually use a slightly pushed power section, it'd be easier than carrying an ac30.

this is exactly how i am thinking now..you could mix and match both and assign one to fx..in fact im going to try it with the hotrod deluxe..iv had a omega mod on that and dont really like the FX loop much ...but the amp sounds great...thinking maybe fx send out of the HRD into a line 6 M13 then into the blues junior...that way just using the blues junior for the fx..

siraxeman

Gassage said:

I know that a 100w amp is about 3db louder than a 50w!!

I got a TSL122 100w 2x12 combo a couple of months ago off ebay. I've done gigs with it and had it on the same volume levels (on the knobs anyway) as my DSL50!! All I really noticed between the two amps is 1 I prefer the voicing of the DSL...but the TSL is still nice, and its a trade off for versatility. And the clean is as is widely accepted...louder or cleaner for longer. Where on the DSL on 5 or 6 there's a little bit of dirt creeping in...on the TSLs clean channel its still pristine and sparkling.. But on the lead channnel of each amp I seem to have 'em set volume and gain wise the same! Both amps use the exact same mix of speakers - Heritage and a V30. (The DSL50 is actually a 1983C Anniversary combo LTD edition combo - basically a DSL 50 in a 2x12 format...exact same amp in a format never previously released before or since).

ICBM

siraxeman said:

I got a TSL122 100w 2x12 combo a couple of months ago off ebay. I've done gigs with it and had it on the same volume levels (on the knobs anyway) as my DSL50!! All I really noticed between the two amps is 1 I prefer the voicing of the DSL...but the TSL is still nice, and its a trade off for versatility. And the clean is as is widely accepted...louder or cleaner for longer. Where on the DSL on 5 or 6 there's a little bit of dirt creeping in...on the TSLs clean channel its still pristine and sparkling.. But on the lead channnel of each amp I seem to have 'em set volume and gain wise the same! Both amps use the exact same mix of speakers - Heritage and a V30. (The DSL50 is actually a 1983C Anniversary combo LTD edition combo - basically a DSL 50 in a 2x12 format...exact same amp in a format never previously released before or since).

This has more to do with the voicing of the amps and the volume control ranges than the difference between 50 and 100W. The TSL is an inherently quieter amp than the DSL - intentionally, at least as far as keeping the clean channel really clean goes - and thinner-sounding. You can't really compare volumes unless you know both amps are reaching the same point, ie usually when the power stage starts to distort - the volume control settings are fairly meaningless.

If you compared the DSL50 to a DSL100 and cranked them both up full you'd hear much more difference.

ChrisMusic

Thanks for the insight ICBM, that post above makes a lot of sense.  (not quoted here for the sake of brevity)

Looks like I was mistaking speaker efficiency for "sensitivity", so it is good to know that cone area is taken into account in that.

The efficient part of the spearers range will be governed by the resistance of the suspension materials and techniques used as well as cone flexure and the thermal compression you mentioned, so as ever, it is not as simple as it looks on the surface.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 

I wonder, do you have a perspective on my earlier post? (quoted below)  I am very curious about this.

ChrisMusic said:   TheGuitarWeasel was pointing out what I would call the "Grunt Factor" or as he eloquently put it "Authority".

How does that factor in to the variables discussed so far, and how do you achieve that "authority" within the SPL limited environments so common nowadays?

Both from a theoretical point of view, and without breaking your bank balance or back in the process.

Is there a psycho-acoustic way of approaching this too?

Danny1969

I was wondering if anyone else has tried sending a clean di to the desk  as well as a mic'ed signal and  re amping the di with Amp farm or Eleven. On a lot of the common desks now, Presonus Studiolive, A&H QU16 etc it's just a case of setting up Reaper or Protools etc to take it's input from the DI channels ASIO stream  and then send the reamped signal back to the desk on another channel. In this way one amp is on stage and one is virtual, existing only in software. Can't get lighter than that. The guy running the desk can choose what virtual amp comes out the PA and can set a mix between your real and virtual amp. That's the way things are going

I'm doing a demo video soon where all the amps are virtual in the desk, so are the drums ... the onstage drums are only triggers

ICBM

ChrisMusic said:

I wonder, do you have a perspective on my earlier post? (quoted below)  I am very curious about this.

ChrisMusic said:   TheGuitarWeasel was pointing out what I would call the "Grunt Factor" or as he eloquently put it "Authority".

How does that factor in to the variables discussed so far, and how do you achieve that "authority" within the SPL limited environments so common nowadays?

Both from a theoretical point of view, and without breaking your bank balance or back in the process.

Is there a psycho-acoustic way of approaching this too?

I find that "authority" comes from bigger amps and heavier cabinets and speakers. That's why I still use a 100W 2x12" combo that weighs almost as much as I do - contrary to what many people say about you "never needing more than 20W" or whatever… it's not about volume, it's about tone - I don't play all that loud. For me, bigger amps simply sound better, even if they're running at low volume. I know full well that this is counter to the normal perceived wisdom that "smaller amps cranked up sound better than bigger ones turned down" - but to me and for the sounds I like, the perceived wisdom is simply wrong.

I do like the sound of many small amps too - I've used and gigged with every size of amp from a Fender Tweed Champ (3W 1x8") upwards, and many of the small amps sound like… very nice small amps. I know other people also claim to get all the 'thump' they want from smaller amps too… maybe I just want more thump . My ideal is at least a 50W and preferably 100W power stage driving at least two 12" speakers with H-type magnets in a big solid cabinet. To me, that sort of amp sounds *better* at *lower* volume than a small amp can - to the point where, also contrary to popular belief, you don't actually need to play as loud, and it will fill a space far better (if you're not relying on the PA entirely to do that).

I really can't decide whether to laugh or get annoyed sometimes when people say things like "are you playing stadiums or something?" or "you must be overpowering the mix" whenever any amp larger than about 30W is mentioned. Amplifiers have volume controls, they can be turned down as well as up.