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15 watts & 94 db eff. speakers: how loud?

With a Trends 15 watt t-amp and small tekton design speakers, with 6 inch fostex 167es, rated @ about 94db, i can get about 93-4 db sustained average (@ 1 meter per speaker) with peaks around 96-7. It sounds perfectly good, nice and clean, no treble break up, nothing different than @lower volumes, only louder.

BUT, at ANY higher volume the amp starts to clip. One hears of many such rigs with even lower wattage 300Bs and such, which is why i wanted the efficiency of the speaker (as well as its single driver design). I've never really used a solid state, much less digital amp before. I'm wondering, is this the nature of hard clipping in digital amps, to begin before there is any real noticeable distortion or is something wrong with the amp? Is this generally how solid state clips? How loud should speakers of this efficiency go with this many t-watts? Finally, how many watts do I need to have some more head room (let's face it, I'm only comfortable with my rig when I know I can accidentally destroy the speakers late one night) : )

Thanks in advance!
thomp9015
joelv's avatar
joelv
102 posts
 
Apologies for my lecture on incorrect math- no more drinking and posting, I promise!

My numbers were supposed to be based on the general rule of 6db increments, not 3db, and for that, it obviously doesn't make sense that the amp is clipping. I even sounded so smug, how embarrassing. I'm terribly sorry to have added to the confusion.

I read (in TAS I think) that 3db is not detectable to the human ear and that 10db sounds like double the volume even though 3db is actually double when instruments are used.

I believe we can all agree that 3db is extremely "detectable" though. I believe 1db is the smallest increment the average human ear is supposed to be able to detect.

Just for reference, I'm a recording engineer by education. I promise you can hear a 3db increase. even from just one instrument.

You just won't need 10x as much power :)
shadorne's avatar
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shadorne
7,333 posts
 
rockadanny - I read (in TAS I think) that 3db is not detectable to the human ear and that 10db sounds like double the volume even though 3db is actually double when instruments are used.

Good critical ears can detect about 0.2 db SPL differences provided it is over a broad range of frequencies in the midrange (as would be the case with volume). Adjustment of treble, for example, by 0.2 db SPL is probably not audible for most people - around 1 db SPL change in treble would become audible to many.
thomp9015 OP
79 posts
 
"My numbers were supposed to be based on the general rule of 6db increments, not 3db, and for that, it obviously doesn't make sense that the amp is clipping." joelv

not sure why it doesn't make sense, could you elaborate for the technically challenged. thanks again for your help and no worries about your mistake, whatever it was : )
joelv's avatar
joelv
102 posts
 
Thomp9015 and anyone interested -

I had posted, incorrectly, that:
The math goes like this: If 1 Watt produces 94db at 1M, then...

97db requires 10 Watts
100db requires 100 Watts

so your amp is behaving quite normally if it clips when the speakers are at SPLs higher than 97db.

Which should have read:

97db requires 2 Watts
100db requires 4 Watts

so it, in fact, does not make sense that a 15-Watt amp would clip when driving the speakers to 98 watts.

Thanks for the chance to redeem myself. :)
joelv's avatar
joelv
102 posts
 
98 db, not Watts. Sheesh!
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