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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
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!
thomp9015 OP
79 posts
 
thank you again joelv, i must say that of everything written so far, and most all of it very useful, yours seems like the best answer to my original question, which is essentially: is this clipping to be expected, and you seem to be saying that it does not appear to be. although i'm about the last to know, my impression is that you are probably correct.

i've emailed both the amp distributor and speaker manufacturer...it may take some time but i will at least get some sort of straight forward response from them both and relay them to you. thanks thanks
shadorne's avatar
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shadorne
7,333 posts
 
Most people are blissfully unaware of compression from speakers. It is possible that your amp was actually putting out around 15 watts during transients and therefore clipping - it is simply that these transients did not translate to the peaks you expected to observe but were limited to 96-97 db SPL.

Explanations for this are - limited Xmax or thermal compression from the driver. Generally about 97% of what you throw at a speaker ends up as heat. The Xmax on this driver is a mere 0.6 mm - a tiny 1 inch voice coil ( no bigger than a tweeter voice coil) I mean $%#^& - what can you possibly expect out of a driver like this????

I have written several times in A'gon forums about the issue of prevalent use of cheap drivers (often used in expensive speakers). They work great at lower volumes but you cannot expect miracles. Soundstage (who do lab tests ast Canada's National Research Council facilities) state that the do not even test speakers with signals above 100 db SPL as this would DAMAGE MOST OF THEM!!!
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