Re: [Harp-L] widening out/opening up the backs of harps



Special 20's are super easy to open. I opened all of mine. They look nice, as for the argument about sound projection, 'bout the same as telling me I'm holding and cupping with the wrong hand. It's an opinion.
Regards, Wil

Sent from my iPad

> On Mar 9, 2016, at 6:25 AM, Randy Redington <rwredington@xxxxxxxxx> wrote:
> 
> Maybe so so...
> But I still enjoy doing it. For some folks it may seem like a waste of
> time, but for me... its fun.
> BTW, I play sp20s.
> I don't cut my cover plates, I just bend them in.
> And I don't bother with side vents like you find on the manji and
> crossover.
> I don't think the volume is affected but I do believe it affects the timbre
> of the sound.
> ---
> Randy Redington
> Surrendered...
> 
> *Sent from my Verizon Wireless 4G LTE smartphone
> 
> 
>> On Mar 9, 2016 5:57 AM, "Rick Dempster" <rickdempster33@xxxxxxxxx> wrote:
>> 
>> I agree, no difference worth noticing; but what, for example, Joe Spiers
>> does makes the plates stronger,
>> so my 'pocket' harp does much better with this particular mod.
>> RD
>> 
>>> On 9 March 2016 at 08:33, Vern <jevern@xxxxxxx> wrote:
>>> 
>>> Widening of the backs of harmonicas will have little effect on the sound
>>> for several reasons.
>>> 
>>> Diffraction is the tendency of sound waves to widen out when passing
>>> through an opening smaller than the wavelength.  This means that the
>> shape
>>> and size of the back opening will not affect the direction of the sound.
>>> See
>> http://www.ck12.org/user:a2VsbGV5dEB1c2QyMDQubmV0/book/Waves-and-their-Interactions-with-Matter/section/1.1/
>>> 
>>> The area of the back opening is huge with respect to the area of the reed
>>> slot.  As a consequence almost all of the pressure drop occurs across the
>>> slot. This means that constriction of air flow by the back opening is
>>> minuscule.
>>> 
>>> The logarithmic response of the human ear makes small differences in
>>> loudness imperceptible.
>>> 
>>> I have covered more than half of the back opening of a harmonica and have
>>> not been able to measure any difference in loudness on a meter.
>>> 
>>> Bottom lineâRobert is correct, flaring the back opening is a waste of
>>> effort.
>>> 
>>> Vern
>>> 
>>> 
>>>> On Mar 7, 2016, at 10:09 AM, Robert Hale <robert@xxxxxxxxxxxxxx>
>> wrote:
>>>> 
>>>>> On Mon, Mar 7, 2016 at 9:45 AM, Peter Beck <kpfbeck@xxxxxxxxx> wrote:
>>>>> 
>>>>> widened out the backs of a bunch of Special 20s
>>>> 
>>>> 
>>>> âI haven't found the result to be worth the work to open the backs of
>>> harp
>>>> covers.
>>>> I consider gapping, embossing, and arcing more worthwhile than flared
>>>> covers.
>>>> 
>>>> NEAR
>>>> There are some variations of sound heard by the player in close
>> proximity
>>>> to the reeds. Since it is a personal experience, one may choose to
>> pursue
>>>> the modification.
>>>> 
>>>> FAR
>>>> I don't think the audience, and most players, can distinguish open to
>>>> closed back harp on stage.
>>>> 
>>>> To evaluate what a microphone picks up, and delivers to an audience,
>>> either
>>>> live thru the PA or recorded medium, we would need to test only ONE
>>>> variable: the open to closed back of ONE model harp.Other variables
>> among
>>>> harps are reed composition / design, comb, choice of mic, and EQ in the
>>>> chain. Again, if the A/B difference is significant to the player it can
>>> be
>>>> done.
>>>> 
>>>> So I place the topic down the list of important activities. Best use of
>>> my
>>>> time is practice and performance.
>>>> 
>>>> Robert Hale
>>>> Serious Honkage in Arizona
>>>> youtube.com/DUKEofWAIL
>>>> DUKEofWAIL.com
>> 




This archive was generated by a fusion of Pipermail 0.09 (Mailman edition) and MHonArc 2.6.8.