From: Mike Curtis Date: Sat, 22 Jun 1996 11:28:53 -0700 (PDT) Subject: Re: Sound levels and resonance (was BG V DT)
> > Some time ago someone was talking about alterations in sound levels on the > harp due to this and that. > > One of my things is that, by using the hands you can resonate most notes on > the harp. The fact is that, if you play a soft note and resonate it, it > becomes a loud note. Thus you are playing the harp softly the whole time > and it therefore lasts a lot longer and you have fooled the audience into > thinking you are playing loudly (like against an orchestra or grand piano) > > I have just been doing some recording on a Yamaha MTX4 fourtrack studio > thing. Looking at the recording level meter I noticed that when I have my > hands off the instrument It is off scale at the bottom. With all other > paramaters the same but with hands correctly positioned for resonance the > meter reads zero. As the meter goes from -20db to zero this means that the > resonance effect is at least 20 db, which is quite a lot. Anyway, it seems > to work. Don't know if the figures are of any interest to anyone or if > anyone else has any figures for the same type of thing.
a 20 dB increase in sound pressure level is a hundredfold increase in acoustic power. When we play amplified, it's the equivalent of replacing a 1 watt amplifier with a 100 watt amplifier - assuming of course that we have plenty of amplifier headroom of course :-) Because our ears respond logarithmically, we will hear +20dB as 4 times as loud.
With 100 times the sound level coming from the harp, we can set the amplifier gain to 1/100th the volume for the same overall volume (and distortion if that's what you want). This is why resonance is SOOOOO important for those playing amplified harp, and why complaints about excessive feedback usually indicate a need to work on resonance.
I've played with some _V_E_R_Y_ loud bands (one holds the record for earplug requests at a club noted for very loud bands - we had a 200 watt PA with efficient speakers that ran most of the time with the "clipping" LED on solidly whenever anyone was singing), and have never had a problem being heard. Sometimes I can't get all the distortion I'd like, but I've always been able to get a decent amount of crunch.
