Heard this one before also
that's the one about the volume knob and that turning it down (reducing the power) blows up the speaker? Hate to be a spoiler but I go with the horse on this one......
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Don't expect the impossible from a 15 inch driver!!
- Thread starter Mark Andrew
- Start date
that's the one about the volume knob and that turning it down (reducing the power) blows up the speaker? Hate to be a spoiler but I go with the horse on this one......
Don't let people try it til they hand you the cash, if then. Don't meet up with anyone who wants to come to your home, and won't meet you in a public place, they're just wasting your time and want to try it out. I don't know why, but people just like to go to other peoples homes and play with their stuff.
those pesky gear-perverts
those pesky gear-perverts
A couple of things, and please (agedhorse, other knowledgeable people) correct me if I am wrong:
Why the difference between mechanical and thermal:
- Historically speaker did not have kapton voice coil formers - they were made out of cardboard, resulting in a relatively low (by today's standards) "Watt" rating. There was not a lot of watt to go around either, so speakers were made with relatively low xmax and power rating (Like EV 15L had 200 W thermal and ~ 140 W mechanical in a TL606 if you have a 4 string bass). So the difference between thermal and mechanical was not that large. However, efficiency is HUGE, so even though you can only put in 140 W I never had a situation where a singel 15L was not enough.
- Then came Kapton voice coil formers and the thermal limit increased ~ 3-4 x without any increase in mech limit - so for most people that meant they can put a lot more power in, but for mechanically limited application like bass that was not a big benefit.
How much to expect from a 15"
- How much a 15" speaker can hold depends HIGHLY on the design of the speaker, the enclosure and the application. EV15L in TL606 is 140 W with 4 - string, and loud enough for all intents and purposes (including heavy metal band). I would be VERY careful using it with 5 string bass and keep an eye on the membrane.
- In the end - it does not matter how much power it holds, it matters how much it puts out. I am confident all properly designed mid and upper price 15" speakers (GK Neo 15, Mesa subway) are adequate for all non-ridiculous situations, and details don't matter much since we don't have control over what we put in anyway (its not like a 350 W speaker will last much longer than a 300 W speaker if you are that close to the limit). So
- 1 x 15" , high quality: Good enough for most gigs, but be careful on large outdoor and listen for distortion. Back off bass will give you enough headroom to make it through the gig, maybe not with your preferred sound.
- 1x15", low quality: Works for small to mid gigs, loud gigs use 2 and you're OK
Closed vs ported cab:
Ported cab can get louder when properly designed but lose control over the speaker at frequencies below resonance, so they are really easy to blow with notes in that region. On top of that, efficiency drops really fast below resonance as you go lower . Higher resonance frequencies give you a higher efficiency but make driver damage more likely (especially if the user compensates for the quick low-bass rolloff with a bass boost) . So, if you have a cheap driver, make up for the low efficiency with a high tuning frequency you get really loud on the A sting but you can blow it out with the low B really quickly. Good driver, lower tuning frequency and proper high pass filter in the amp gives you high volume at low power, high maximum volume, and safe operation.
Closed cabs don't suffer from that - they just need lots of power, but can't handle a lot of it because the resonance is not well damped. They work really well below resonance frequency compared to ported cabs, thats why amps that put out a moderate amount of really low frequency signal are less likely to blow up a sealed cab (but they won't blow up a low tuned ported cab either).
Euphonic Audio's designs combine the higher efficiency of ported cabs with maintaining driver control below resonance frequency through their transmission line tuning. Expensive, but great sound, compact design, and loud for the size.
Tube vs SS watt (vs class D watt)
Yup, the 30 W Ashdown Little Bastard has its name well deserved. Why is that?
a) Tube amps are really good at handling signals above their capability. Tubes jut a little cream sauce distortion on top, if you do the same with a (not compressor protected) SS amp it sounds like someone took a chainsaw to it. Class D simply go into protection mode if you try to squeeze stuff out beyond what they are designed to do.
b) ...the cream sauce on top is really easy to hear and it give your the impression it is louder, and you can hear yourself better because of it.
But yes, Ashdown Little Bastard is loud, and even low powered tube heads are really useful, and you need a lot more power in a SS head and even more in a calss D to get the same usefulness.
Why the difference between mechanical and thermal:
- Historically speaker did not have kapton voice coil formers - they were made out of cardboard, resulting in a relatively low (by today's standards) "Watt" rating. There was not a lot of watt to go around either, so speakers were made with relatively low xmax and power rating (Like EV 15L had 200 W thermal and ~ 140 W mechanical in a TL606 if you have a 4 string bass). So the difference between thermal and mechanical was not that large. However, efficiency is HUGE, so even though you can only put in 140 W I never had a situation where a singel 15L was not enough.
- Then came Kapton voice coil formers and the thermal limit increased ~ 3-4 x without any increase in mech limit - so for most people that meant they can put a lot more power in, but for mechanically limited application like bass that was not a big benefit.
How much to expect from a 15"
- How much a 15" speaker can hold depends HIGHLY on the design of the speaker, the enclosure and the application. EV15L in TL606 is 140 W with 4 - string, and loud enough for all intents and purposes (including heavy metal band). I would be VERY careful using it with 5 string bass and keep an eye on the membrane.
- In the end - it does not matter how much power it holds, it matters how much it puts out. I am confident all properly designed mid and upper price 15" speakers (GK Neo 15, Mesa subway) are adequate for all non-ridiculous situations, and details don't matter much since we don't have control over what we put in anyway (its not like a 350 W speaker will last much longer than a 300 W speaker if you are that close to the limit). So
- 1 x 15" , high quality: Good enough for most gigs, but be careful on large outdoor and listen for distortion. Back off bass will give you enough headroom to make it through the gig, maybe not with your preferred sound.
- 1x15", low quality: Works for small to mid gigs, loud gigs use 2 and you're OK
Closed vs ported cab:
Ported cab can get louder when properly designed but lose control over the speaker at frequencies below resonance, so they are really easy to blow with notes in that region. On top of that, efficiency drops really fast below resonance as you go lower . Higher resonance frequencies give you a higher efficiency but make driver damage more likely (especially if the user compensates for the quick low-bass rolloff with a bass boost) . So, if you have a cheap driver, make up for the low efficiency with a high tuning frequency you get really loud on the A sting but you can blow it out with the low B really quickly. Good driver, lower tuning frequency and proper high pass filter in the amp gives you high volume at low power, high maximum volume, and safe operation.
Closed cabs don't suffer from that - they just need lots of power, but can't handle a lot of it because the resonance is not well damped. They work really well below resonance frequency compared to ported cabs, thats why amps that put out a moderate amount of really low frequency signal are less likely to blow up a sealed cab (but they won't blow up a low tuned ported cab either).
Euphonic Audio's designs combine the higher efficiency of ported cabs with maintaining driver control below resonance frequency through their transmission line tuning. Expensive, but great sound, compact design, and loud for the size.
Tube vs SS watt (vs class D watt)
Yup, the 30 W Ashdown Little Bastard has its name well deserved. Why is that?
a) Tube amps are really good at handling signals above their capability. Tubes jut a little cream sauce distortion on top, if you do the same with a (not compressor protected) SS amp it sounds like someone took a chainsaw to it. Class D simply go into protection mode if you try to squeeze stuff out beyond what they are designed to do.
b) ...the cream sauce on top is really easy to hear and it give your the impression it is louder, and you can hear yourself better because of it.
But yes, Ashdown Little Bastard is loud, and even low powered tube heads are really useful, and you need a lot more power in a SS head and even more in a calss D to get the same usefulness.
Sound advice. This guy had a caravan in a forest fairly close to work so I took it there he cranked his bassman to 11 in the forrest and was surprised when no trees fell over.....
and my cab farted out big time. Think that qualifies as an outdoor venue...
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I think this is more the issue than how many watts a certain speaker can actually take. You have to figure out how to let people demo your cab without abusing it. Maybe you play through it at limits you set and then they can make up their mind etc. As per the above, you can control it when you own it etc.
That really is irritating, when people just want to crank your cab to see how loud it will go. I bring down a pretty decent PA to our local church to play at a party or whatever once in a while. You have to watch all the time for some yahoo who wants to abuse it. I get the rant.
Oh, agedhorse, just for clarification - the mechanical rating of 400 W for the subway, it that 400 W of white noise and the 67 Hz band of the white noise causes the voice coil to hit the magnet (I assume the 400 W number is the destructive number, not where it begins to distort) or is that a 67 Hz sine wave signal?
BTW, for all intents and purposes the 12" subway cab with a high pass filter in the amp is enough to play almost any gig with PA support (I played Toby Keith in Foxboro with it, or the Tin Rooster in NY). Never ran into any issues with NL-210 either, nor with the 12" wizzy, nor with the BA123.
BTW, for all intents and purposes the 12" subway cab with a high pass filter in the amp is enough to play almost any gig with PA support (I played Toby Keith in Foxboro with it, or the Tin Rooster in NY). Never ran into any issues with NL-210 either, nor with the 12" wizzy, nor with the BA123.
All the way down to zero Hz? Most folks forget/don't realize that the bass guitar puts out frequencies below the lowest string's tuning. An acquaintance of mine keeps lunching the cones in his 410 Hartke cab - you can see the cones trying to depart the cab every time one is struck
. The older SWR head he has has no HPF 
.
Just a brand new stock replacement as I hammered the thing for years sorry decades and though it was a good idea. New driver has tighter sound but the old one takes more of a hammering it may go back in for those wrong side of town gigs
.They were supposed to be identical.....
You musta played in quiet bands - I needed two or three 15's in the bad old days to keep up with a couple Marshall 50w half stacks. Maybe one of the latest super xlim ones but I still generally go with two drivers these days, because why drive the snot out of a single when you don't have to?
No speaker will handle DC for long.
Most folks forget/don't realize that the bass guitar puts out frequencies below the lowest string's tuning. An acquaintance of mine keeps lunching the cones in his 410 Hartke cab - you can see the cones trying to depart the cab every time one is struck
Nah - they pretty much ALL have an inherent HPF (although it may be too low for a particular cabinet) - you don't see too many DC coupled audio amplifiers.
A couple of weeks ago I played a car show and tried out my new 1x12 cabinet along with my 1x15. I heard the 15 going through it's objection to my volume, and knowing that it is a 300w Beta, I knew what was going on right away. The new 1x12 with 3012lf sure sounded good with the 1x15, but I'll need some more beef there I guess.
The pickups probably have an inherent HPF higher than these older design amps
. And who didn't love the crown DC coupled amps AKA smoke show generators? LOL
All satirical humor my friends. Why so serious?Heard this one before also
D
Deleted member 165050
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This is a new one on me also I will second that .... zero hz? How does that work? I will go and put on the sound of silence for a bit of inspiration .........
- Feb 12, 2006
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- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
No, we look at linear displacement versus power & frequency, where it becomes non-linear. This is typically about 1.1x the published Xmax due to the additional interaction with the fringing mag field. Not all drivers have as much fringe control, one aspect that contributes to graceful overdrive. Hitting the back plate is way beyond this (and not healthy for the speaker)
Note that mechanical power handling varies with frequency, at very low frequencies power handling can fall at between 6 and 12dB/octave. By incorporating a HPF, this effect can be cancelled to a large extent.
Any string vibration is transmitted via the pickup, as far as I know. The pickup isn't restricted to frequencies that we can hear or that cabs can produce. I'd bet percussive muted strum sounds still get transmitted, and they can have a frequency down to 0 Hz. If you don't have a filter somewhere in your chain, the amp will send a signal to the cab and the cab's mechanical limits will become the ultimate filter.
The post you referenced said down to zero Hz, which would obviously be silence. Anything between 0 and 20 Hz is still an oscillation even if inaudible because of human perception limitations.
