Speakers for Tube Amps.

[Sea Chief]

Hi chaps- Ive been playing gtr for 30yrs, and tinkered around with a few basic tube amp builds in last few yrs, but still find speaker (sensitivity/ wattage) specs utterly confounding, bar the basics of this rule of thumb for eg: a 100db spkr will simply be louder than a 96db.

What confused me most, from experience, was my bog-std 5E3 build. I aimed to get some "break-up" (as we all do) but found it totally impossible without blowing my ears off, and subsequently (only within minutes of just finishing the build) having neighbours (all of 300m away) storming over furiously demanding I 'turn that down' and swearing at me. It was loud I admit, but confoundingly I had only just managed to get some break-up at this huge volume, vol around 6. I have, therefore, only -once- in my life been able to hear natural break-up. I haven't dared turn vol past 3 since- its just too loud, and so Ive never used the amp since as low tones are unintersting. A complete waste of money and alot of time.

What flumoxes me is the speaker was a 'standard 5E3' Jensen C12N 50w, 98db. Now if I had used a 300w speaker, and rated at 110db I would understand the massive volume & why my neighbour was so furious. But this is a standard -and recommended- 5e3 spkr. Its rated at 50w, and not excessively high on the db scale either afaict. I see some folks even on YTube clips with 5e3 amps in front of the camera calmly strumming away with similar natural break-up as I got at say 6.. but without even the cam-mic overloading, the dog going mad, thudding on the door from X next door. Im -UTTERLY- bewildered. How did they do that?

So what is the deal here? did I get the spkr rating wrong? should it have been 85db? (if thats possible), and /or did I get the wattage rating wrong? its only a 15w amp, so was 50w way to high or something? And what charcteristics does a 50w speaker have that a similar (C12K for eg) sensitivity spkr have albeit double the wattege at 100w?

Thx for any ideas /replies. SeaChief.

[ReadyTeddy]

Fender amps have lots of gain, so at a setting of 6, and in order to hear breakup, the amp was probably saturating on the loudest notes, and putting out in excess of its 15-watt rating. If a speaker puts out 98 dB at 1 watt, it will put out about 120 dB at 15 watts--that's pretty darn loud. Of course, you have to read speaker ratings carefully--they are usually rated for one watt input power with the microphone on axis 1 meter away in an anechoic environment. It's virtually impossible to translate what volume level that will mean in a room given the myriad of variables. I also might ask, what are you trying to break in? If you want to "break in" an amp, just leave it on for a while--the amp won't dissipate appreciably more power by putting a signal through it. Personally, I think amp break in is mostly hogwash. If you're trying to break in a speaker, feed in a sinewave at a frequency near the speaker's resonance--this won't produce a sound that is exceptionally loud and obnoxious, and because you're driving the speaker near resonance, it won't take much power to exercise its cone. If you take the speaker out of its cabinet while you're doing this, it will put out very little volume. I also suspect that speaker break in is mostly hogwash.

[Sea Chief]

Hi Teddy,
thanks but unfortunately I just dont understand a word there, its far too technical. Im not after understanding the technical reasons per se here, its simply 'how come that bloke strums his 5e3 & can even record it in an appartment.. but when I get a similar nice sound, its so physically loud for me it nr hurts so totally impracticle, & so loud it caused immediate nr police complaints for neighbours (all of 300 metres away)".

An appartment?!?

Lets assume my speaker specs similar to his (likely- as said mine was recommended, and used extensively, in std 5e3 build its a C12N @ 50w/98db).

IE either blokes volume was say at 6 far, far -FAR- lower (I assume it just had to be if recorded lazily in bare feet one morning in his flat) than mine, or my volume was far far, FAR higher (for some reason). The discrepency I can only attest to being a speaker thing [[unless proved otherwise]] but if we have the same (lets assume very similar indeed as is likely) speakers = a total mystery.

[Enzo]

You are focused on just ONE parameter of a complex formula. Life is not that simple.

3 decibels is not a very large difference in loudness. In fact, the difference between the high and low input jacks on most fender amps is 6db. Decibels are logarithmic. If you double the power from the amp, the loudness increases 3db. If you keep power the same, but make the speaker 3db more efficient, you get the same 3db loudness increase. But 3db is a noticeable change, not a elephant versus mouse change. All else being equal, a 100db speaker will be slightly more than 3db louder, not much. If you double the power, then double again - 4 times the power - you get the same 6db difference as those Fender input jacks. Same difference as a 98db speaker and a 104db speaker. And even using that lower gain input jack, you still can get plenty loud on most any Fender.

Reasy was talking about breaking something in, while you are talking about breaking something up. Those are entirely different subjects.

Breakup is a term that can be applied to more than one thing. There is speaker breakup, where we exceed the comfortable excursion of the speaker, and thus the speaker itself adds some distortion. Then there is power tube breakup, wherein we push the power tubes past their limits and overdrive them into distortion. Have one or have the other or have both. You can also overdrive the preamp section of an amp to get some breakup. Preamp distortion can occur at low levels, just overdrive an early stage, then dial down the volume in a later stage. But speaker breakup and power tube breakup can only occur at the maximum levels, because they are based upon exceeding the limits of the tubes or speakers.

If someone is getting actual speaker or power tube breakup from a 5E3, then it was not happening at conversation levels. That is one reason many people use attenuators. also called power soaks. You insert the device between amp and speaker, and it uses resistors (more or less) to use up a low of the power before it gets to your speaker. SO you can hear the sound of the overdriven power tubes, but at lower loudness.

But someone could also be getting preamp distortion, which does not rely on overdriving either power tubes or speakers.

[pdf64]

If the amp is getting 'natural break up' then it's being pushed into overdrive, the volume control setting is immaterial.
Assuming 15 watts then it's putting out at least that (actually 5E3 compress a lot due to the saggy screen supply, so the overdriven power doesn't tend to be much more that the clean power).
So, with your C12N 1 watt will give 98dB, 2 watts 101dB, 4 watts 104dB, 8watts 107dB, 16 watts 110dB.
As you've commented, that's horrendously loud in a domestic scenario.

If you want power amp overdrive at an acceptable volume, with a regular guitar speaker, 1/10 watt is plenty.
Hence micro amps, VVR to drop the B+/power output, attenuators, or my preference, a Fluxtone speaker FluxTone Speakers reduce speaker volume without tone destruction
There's no easy cheap answer unfortunately.
Pete

[Sea Chief]

I realise that -technically- the break-up both Bloke A and myself got is a relatively complex thing. But Im not concerning myself with trying to understand the technical minutiae of why an amp breaks up with this thread. That has to do as you say with a+b+c paramenters interacting together I understand the basics of this.

Im simply trying to understand why if two amps are the same and one breaks up at 6 and is quite loud [but playably so as it is able to be recorded in a room] but the other breaks up at 6 and is MASSIVELY loud [so much so its nr physically painful].. there is seemingly and by all accounts I have envisaged such an ENORMOUS difference in SHEER VOLUME.

My Q -- and discounting attenuators-- is why/ how come? I think it must be to do with speaker, if (as the above eg uses two similar amps in two similar cabinets) Ive surely therefore ruled out all other reasons.

[Sea Chief]

So how did Bloke A record his 5e3 amp in break-up?!? theres no evidence he or his recording equipment is remotely troubled by any excessive volume.. so I must assume there wasnt any. You can see a good few eg's on Youtube of 5e3s in break-up; I just dont understand how they got there, let alone how on earth they recorded it without the mic (or their ears, or even the walls) exploding......................... unless the volume I produced was somehow hugely OTT compared to any other 5e3.

No-one else on the 5e3 forums or discussions builds etc Ive read ever complained of massive volume issues with a 5e3 (afaict). Ive certainly never heard of examples of neighbours rushing over (I was at a detatched house in a good acre of land around) 300m furious & threatening such was obviously the volume I admit I was making. No, they just "record it on a cam in their appartment and put it on YouTube".

There is just such a huge disparity.

[pdf64]

My guess is that the disparity is in the reaction of you and your neighbours to the noise, rather than sound level itself - overdrive a guitar amp and a lot of noise is created, that's the nature of the thing.
A P12R would reduce the sound level by 3dB but the resulting 107dB would probably be as unacceptable as 110dB.
Some camcorders cope with high sound levels better than others, some I've used distort dreadfully when recording the band, some hardly at all - again just one of those things.
Pete

[Leo_Gnardo]

To quote from the sage Keef: "Neighbours neighbours neighbours neighbours.... " Some people will bug out if they hear ANYTHING. I could tell you some stories ... but today I'll spare everybody that. Lucky for me, my neighbors are busy with all their nefarious activities & probably don't want to call attention to themselves when I light up an amp. I also keep my noise making to "social hours" 9 AM to 9 PM. 300m, that's @ 1000 ft, my they are sensitive aren't they?

One thing you might want to be on the lookout for - an old speaker with a magnet that's lost most of its field.* For most folks, that's something fit for the junkpile, but in your case, could be an asset. Had an early 60's Sano with one of these. Amp only turned out @ 9W @ clip, and I could dial it up to 10 & wail, not much louder than a clock radio. Terrific tone from those EL84's getting crushed. Sold it & soon the buyer was back, needs louder. I sold him a new Jensen C12Q & he got happy.

In a well insulated house, in a neighborhood where there's plenty of ambient noise, you can get away with it. Yes there's a very wide variation in volume acceptance.

*This could be simulated with a field coil speaker, and not much current being run through the field coil. Eminence sells a variable-field speaker but the price? Don't even think about it. If you can locate a working FC speaker, build a little variable power supply out of scrap parts, that would be the ticket.

edit: to expand a little on pdf64's to-the-point observation, some camcorders do have a very nice compressor/limiter built in, and don't even mention it. ALSO our ears do much the same when confronted with loud continuous volume. You could do a Basil Fawlty and recommend they remove the batteries from their hearing aids.

[Sea Chief]

Ok I undertand it -could- be my appraisal of the volume being excessively high + a camcorder's possible ability to actually record such tremendous noise. But Im far from convinced either of those, or the probabilty both our amps were at anywhere near the same actual volume (either bloke A's amp somehow -how Ive no idea- broke up way before 6.5 OR my headroom somehow vast & was more akin to a fender Twin than a 5e3).

But look, if I was in a terraced property and neighbour came sternly asap furiously knocking then fine: its loud, they are really close: I understand. This guy though was a 40 s'thing stocky b'stard who trooped perhaps 400 metres incensed at the volume whacking the door it was so ferociously loud. It just was. Absolutely totally never unuseably so as well, I woudnt have had any drummer suffer that volume it was that loud. I had no choice if I wanted (for all of the 2minutes I was ever able to hear the f**king thing) to finally hear my amp, cranked.

Either it was the build somehow I made w'out meaning to with such late break-up/ large headroom, or it is simply the speaker. I must therefore assume it was the speaker as break-up at 6.5 is what one would expect with a 5e3. And therefore 50w is simply hugely overkill, and/ or 98db is hugely OTT.. but I dont understand either of these factors on volume (or think a 50w/98db spkr is indeed wrong at all) = STILL an utter mystery.


**Can someone just tell me: what would I have heard if instead of my 50w/98db (Jensen C12N) speaker I had instead installed a 25w/94db (C12R)? lower volume? earlier break-up? barely anything at all? or plain no difference whatsoever?

[Steve Conner]

That is just how loud a cranked 5E3 is. If you think that was too loud, try a Marshall stack.

Neighbour sensitivity varies widely, and so does the ability of recording equipment to cope with extreme sound levels. The consumer camcorders and phones I've tried can't handle my amps cranked, and my neighbours couldn't either. Living in an apartment I got complaints running 0.3 watts into an 8" speaker. Running 60W into a 98dB efficient speaker (EVM12L) I get complaints from sound guys at smaller gigs. I don't think I've ever heard a rock drummer complain about excessive stage volume. Usually they are the cause of it.

A 100 watt Marshall stack with 8 12" speakers is massive overkill, a relic from the days when the PA system was for vocals only and the guitar amp had to fill the whole venue with sound.

[g1]

I think the main problem is that you are trying to compare it to something you are seeing and hearing on youtube. Perhaps if you went to a music store and tried out an amp of similar power driven to breakup, you would see just how loud 15 watts can be.
It's impossible to say what's going on in the video. He could have the mic setting turned way down, and may be half deaf for all we know .

[potatofarmer]

**Can someone just tell me: what would I have heard if instead of my 50w/98db (Jensen C12N) speaker I had instead installed a 25w/94db (C12R)?

It would be slightly quieter. I just wanted to point out something others have missed - the "wattage" of a speaker only means how much it can handle without blowing up, it has nothing to do with how loud it is. If you used a 100W or a 300W speaker with the same sensitivity, it wouldn't be any louder than a 25W or a 50W speaker (assuming the sensitivity is the same).

Was this a small, really reflective room?

I understand that the issue is that even you think it's too loud, but I'd check the local residential noise statues and then tell the neighbor to go pound sand and stop trespassing.

[Leo_Gnardo]

but I'd check the local residential noise statues and then tell the neighbor to go pound sand and stop trespassing.

Lot of variation in those regs AND how they're applied. New Politically Correct laws in some areas allow noisemaking for some purposes between certain hours. For instance here it's OK to run lawnmowers etc. from 7 AM to 8 PM. (Sunday included, and some neighbors start with the lawnmower at 7 AM Sunday. Grrr....) BUT - and a big BUT it is - if a neighbor doesn't like your music, from hi fi, party, guitar jammin', practicing saxophone, bagpipes, banjo, viola, drums, whatever, they can lodge a complaint at any hour and it's - theoretically - enforceable. So it's off to the hoosegow, you and your guitar. All depends on who the complainer & complainee are. Especially if you are a relative or friend of the police, judge, politician etc. Some people get away with anything & everything, noise, junk vehicles, rubbish in yard, burning garbage, dope sales, on up the ladder, you name it.

Might just have to get a power attenuator between your amp & speakers. And hope your neighbor isn't pressing his ear up to your door.

[Steve Conner]

I remember when I loaned one of my DIY amps to my brother and he nearly got it confiscated by the police.

So much depends on the situation. If you live in an exceptionally quiet area of the countryside, the sound of an electric guitar might be objectionable even a quarter mile away. There may even be places in the world where the neighbours haven't heard one yet.