2. amps-preamps
  3. 1216064971

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

Showing 4 responses by shadorne

shadorne's avatar
shadorne
7,477 posts
 
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?

Yes this is normal. SS amps generally clip all of a sudden and they can sound very bad when clipping. The main advantage of tubes is that they "soft clip" - a much more pleasant and often cherished sound. As a general rule you should try to ensure that SS amps do not clip with tubes it is a matter of taste - a bit of clipping can add significantly to their rich sound.
shadorne's avatar
shadorne
7,477 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.
shadorne's avatar
shadorne
7,477 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!!!
shadorne's avatar
shadorne
7,477 posts
 
Thomp9015,

I am not saying it is a bad driver. At $65 retail (probably less wholesale or in bulk) this is a great and well respected driver and will sound awesome at lower volumes than 97 DB SPL.

All I am really saying is not to expect too much - after all to get good clean loud sound above 100 db SPL you are probably looking at something much bigger - a three way or something with perhaps $600 or more worth of drivers. You know - don't expect miracles - or don't believe the math that suggests that a small 94 db SPL full range driver should be able to easily play 110 db spl comfortably (with pure theory suggesting that all you need is a big power amp).

Of course amplifier manufacturers often neglect to mention this as they are often trying to sell you higher end amps with more watts...in a sense they are competing with speaker manufacturers for a piece of your overall "system budget."
More to discover