Speaker db

[sonny bunz]

Hi all,

I'm new to the vintage scene and just setting up my first system. I have a 20 watt amplifier and a turntable but require speakers. With such a low wattage amp do I need to limit my db frequency for speakers or does not matter?

Cheers.

Sonny Bunz.

[Alec124c41]

The specs for speakers say something like, "89 db with 1 watt at 1 meter."
This means that 1 watt of signal will produce that sound level. Higher numbers signify a more efficient speaker, lower ones mean it will need more power to produce the same sound level.
With 20 watts, you want efficient speakers, around 90 db or more.

Cheers,
Alec

[sonny bunz]

Thanks Alec,

So db have no impact on sound quality on small wattage amps? I have no intention on blasting my myself or my neighbors to the moon. In other words it doesn't matter what db speaker I get if I don't want to play the music loud?

Thanks.

Sonny Bunz.

[MonkeyBoy]

No, it has no actual impact on the sound quality coming out of the speakers. It's merely a measurement of how efficient the speakers are. If you look at one of those visual aids that tells you how loud different Db levels are you will see that 90 decibels is quite loud, so any speakers that produce 90 Db at 1 watt at 1 meter can be very loud with minimal power. Very little of my listening is at levels this loud. Mozart and Sinatra tend to sound not so great at such volumes. The Who sounds great at volumes much higher. Very nice sounding speakers can be found at every level of efficiency.

[jackfish]

Please use the correct term when discussing this speaker specification. Efficiency is not the same as sensitivity.
http://en.wikipedia.org/wiki/Loudspeake ... ensitivity

[sonny bunz]

So in laymens terms, the lower the wattage amp the higher the db speaker?

[Eoin]

Yes.

As Alec suggests (not my area, but Alec knows his stuff), try a speaker of more than 90db/W on a 20W amp.

A higher dB/W number on the speaker means it'll be playing more loudly at the same amp output than a lower number.

[Hanuman]

No, it has no actual impact on the sound quality coming out of the speakers. It's merely a measurement of how efficient the speakers are. If you look at one of those visual aids that tells you how loud different Db levels are you will see that 90 decibels is quite loud, so any speakers that produce 90 Db at 1 watt at 1 meter can be very loud with minimal power. Very little of my listening is at levels this loud. Mozart and Sinatra tend to sound not so great at such volumes.

Quite so, but most listening positions are greater than 1 metre from the speakers. There's about a 6dB drop every doubling of distance and you'll need 4-times the amplifier power to get that 6dB back. Power requirements can escalate quite dramatically. A 3dB increase in sound pressure level (just a slight increase) requires a doubling of amplifier power; 10dB extra (double the apparent volume) needs a ten-fold increase! So, if 90dB is the limit of your requirement, and chamber works probably don't go much above that normally (but nothing would surprise me), and you're listening at 2 metres then your 20-watt amp will stay unstressed. But, if you need Led Zepplin to sound at a level more befitting, say 95dB (still not loud enough, though), the 20-watt amp will be only 1 or 2 dB away from clipping. At 2-and-a-half metres the 20-watter won't be able to do it. If you want to get to 98dB, still below what's needed for a rock band, you'll need 25 watts at 2 metres with no headroom at all. At 3 metres you'll need nearly 60 watts for 98dB and you'll have no headroom still.

90dB sensitivity rating is probably higher than average for high-quality hi-fi speakers - there are plenty of famous speakers with a spec. of lower than that. For a stereo pair rated at 87dB@1W@1m you'll get no more than 94dB from your 20 watts at 2 metres, with no headroom.

This all explains the existence of high-powered amplifiers in homes.

I accept that my figures might be rubbery and I apologize in advance for that but I think I won't be too far out.

[PeterW.]

Hi all,

I'm new to the vintage scene and just setting up my first system. I have a 20 watt amplifier and a turntable but require speakers. With such a low wattage amp do I need to limit my db frequency for speakers or does not matter?

Cheers.

Sonny Bunz.

*Gleep*

OK - For every perceived doubling in sound volume (10dB), you need to increase amplifier power by a factor of ten. So, if your speakers make 90dB @ 1 meter @ 1 watt, to make 100dB, you will need 10 watts. To go up to 103dB, you will need 20 watts. To 110dB, you will need 100 watts.

This is called "headroom" and how much it means to you depends on three basic factors:

a) The overall efficiency of your speakers.
b) The general volume at which you prefer to listen.
c) The general peak-to-average of the signal you are feeding into the speakers.

So, if you listen to head-banger music (very limited P:A) at a moderate volume on efficient speakers, your 20W amp will be just fine.

If you listen to some very few Direct-to-Disc recordings with a 30dB P:A and into inefficient speakers you will run out of headroom and go to clipping much of the time. Which, depending on amplifier design is either bad enough or directly threatening to your speakers - but never good.

If you like to listen to _anything_ at near-ear-bleeding levels, 20W will simply not cut it. Sound is all about moving air - and 20W will not move enough air for that need.

I run a 17W/Channel RMS tube amp into AR 4x speakers in a small room and listen mostly to classical music with some folk and bluegrass mixed in. It does very well - tubes have "soft" clipping and I do not attempt to influence my neighbors by volume.

I also run a 225W/Channel RMS SS amp into Maggie speakers. For my DD Saint-Saens Organ Symphony, I use every bit of that - and although conversation would be nearly impossible in the listening room at that volume, the sound is not the least bit oppressively loud - even for my wife, the cats or the dogs.

It is all about those three factors.

Peter Wieck
Melrose Park, PA

So, it is all about those three factors.

[Ldg]

My 2p worth. From opera to classical to Led Zep, it's necessary to be able to create the correct SPL. Whatever the listening position, IMO this means ability to create accurate sound levels of at least 105dBC, preferably quite a bit more.

IMO it's worth investing in a cheapo sound level meter, if nothing else because playback level makes a big difference to overall perception, no matter what programme material.

In the end, one realises there's only near field or serious power levels for critical listening, IMO. Near field with good headroom is tough to beat, though I have setups for NF and full room. Listening closer to full room speakers can work too. As always, one should be aware of long term high SPL exposure.

[charlieblue]

When my el-cheapo-made-in-PRC-German-brand SPL meter shows peaks above 96 dB, the sound usually gets too loud for me... might blame the untreated bare-wall listening room for that Still, on occasion I have found myself to enjoy +100 dB for metal or orchestral music: it adds this feeling of liveliness to the experience...

The other day, visiting a friend, we auditioned his brand new speakers and homemade valve amp. His smallish push-pull puts out no more than 20 watts, but with 93dB@1m - I would guess the the 96dB published spec is for both channels driven - of energy ( pun intended ) coming out of these babies http://www.energy-speakers.com/search/?sku=CF-50, we rocked the place even at +3 meters in his >40m2 living room.

In any case, yes, go for +90dB per loudspeaker. Better to turn the volume knob down if the sound gets too loud, than yearn for that extra punch you know you like, but just isn't there...

[sonny bunz]

Thanks for the info guys, most helpfull. Im limited by my budget which is around $250 US, looking at 70's, early to mid 80s, 90db+, maybe Kef? (Tannoy seems to be a bit out of my league). Again this is my first set up so my learning curve is pretty steep. Any suggestions?