Re: [Harp-L] Chromatic cover lids modification
Vern to me you are the James Randi of the Harmonica world....and that is a
Aside from the physics involved........I would also wonder why anyone would
want to open the backs of a harmonica,especially if they were playing
amplified Blues Harp.
There has been A lot of discussion over the years about amplified
tone and one of the crucial things mentioned is the complete enclosure of
the harp to get that 'overdriven ' sound.David Barrett has a whole U Tube
series on how to 'cup' the harp and mike to make it airtight.
Opening up the covers I think would make that airtight seal even
harder to achieve.
----- Original Message -----
From: "Vern" <jevern@xxxxxxx>
To: "Denny Noreikas" <harpmessin@xxxxxxxxxx>
Cc: "Harp- L" <harp-l@xxxxxxxxxx>
Sent: Friday, January 14, 2011 18:32
Subject: Re: [Harp-L] Chromatic cover lids modification
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
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
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.
On Jan 13, 2011, at 6:19 PM, Denny Noreikas wrote:
That is interesting. I wonder why the new trend in diatonic harmonicas is
open back? They do seem louder to me but are also more susceptible to
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
Opening up the Velvet Voice covers would be a waste of your time.
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
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.
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