Re: [Harp-L] Chromatic cover lids modification

[Denny Noreikas <harpmessin@xxxxxxxxxx>]

Vern,

Thanks. You have convinced me to stay the course. What you say makes  
sense to me.

Denny


On Jan 14, 2011, at 12:32 AM, Vern wrote:

> If many buyers think, as you do, that openings in back of a  
> harmonica have a perceptible effect on loudness, the manufacturers  
> will cater to those beliefs, whether or not they are true.  Hohner  
> has actually claimed that different  types of wood used for combs  
> produce perceptible differences in tone!  Manufacturer's, in an  
> effort to differentiate their harmonicas from those of the  
> competitors, will often make claims that are not fully justified by  
> acoustics.  A common ploy is to exaggerate some minuscule effect.
>
> Hearing is a very subjective sense.  Listeners will report hearing  
> what they expect to hear.  It requires testing under very carefully  
> controlled conditions to avoid these subjective effects. Knowing  
> whether the opening in back is larger or smaller will affect what  
> you think you hear.
>
> Human hearing is logarithmic.  Sound level is measured in decibels.   
> An agreement is made on a reference level of sound pressure that is  
> barely perceptible to the "average" person.  Then the db level of a  
> sound is ten times the logarithm of the ratio of the sound pressure  
> to that reference.  A human can barely detect a sound level change  
> of 3 db where the level is suddenly changed....as in an A/B test of  
> hi-fi speakers.   Yet a 3 db increase is a doubling of the sound  
> pressure!   If you listen to a sound in a room, then go to lunch and  
> come back to the room to hear the same sound at a different level,  
> it takes a very much larger difference to be perceptible.
>
> Any slight change in the opening will have only a small % change in  
> the level and will be imperceptible to your ear.
>
> However, it is your harmonica and your ears.  If you do not find my  
> arguments persuasive and you want to cut or bend open those covers  
> and rejoice at the increase loudness, have at it.
>
> Vern
>
> On Jan 13, 2011, at 6:19 PM, Denny Noreikas wrote:
>
> > Vern,
> >
> > That is interesting. I wonder why the new trend in diatonic  
> > harmonicas is a more
> > open back? They do seem louder to me but are also more susceptible  
> > to denting.
> > I'm confused.
> >
> > Denny
> >
> >
> > On Jan 13, 2011, at 7:03 PM, Vern wrote:
> >
> > > The curling in of the cover plates does not perceptibly suppress  
> > > the sound.  I once blocked off more than half of the opening in  
> > > the back of a harp with an aluminum plate.  There was no  
> > > perceptible difference in the sound as measured on my sound-level  
> > > meter.   When you cup a harp in your hands, there is hardly any  
> > > effect until your hands are almost closed.
> > >
> > > Opening up the Velvet Voice covers would be a waste of your time.
> > >
> > > Vern
> > >
> > > On Jan 12, 2011, at 5:27 PM, Denny Noreikas wrote:
> > >
> > > > All this recent talk about which Chromatics to buy got me  
> > > > thinking about trying the
> > > > Chromatic again for playing Blues. I have 2 key of C's, a Hohner  
> > > > CX-12 and a Hering
> > > > Velvet Voice 48. The CX-12 is too shrill for me compared to the  
> > > > Velvet Voice. I like the
> > > > rich smooth sound of the Velvet Voice. However, the top and  
> > > > bottom cover plates on the
> > > > Velvet Voice curled around toward the comb in the back of the  
> > > > harp which narrows the
> > > > back opening suppressing the sound. I am sure this is by design.
> > > >
> > > > The CX-12 has a very large opening in the back. Can the cover  
> > > > plates on the Velvet
> > > > Voice be filed down with a Dremel tool or similar device to open  
> > > > up the back? I am not
> > > > a customizer nor do I want to screw-up a perfectly good harp.
> > > >
> > > > Any help would be appreciated.
> > > >
> > > > Denny