Cherry and WRC Parlour sprectra question
- Francis
- Myrtle
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Cherry and WRC Parlour sprectra question
I'm working on a small parlour which is currently at the closed box stage - neck/bridge not fitted. Tried some tap tests at the bridge position using a phone app. Would like comments on the spectra please:
The guitar so far:
Soundboard is Falcate braced with CF top and bottom of all braces. Back is radially braced.
Other images of the build/bracing can be seen here: http://milsomguitars.weebly.com/heathers-parlour.html
The guitar so far:
Soundboard is Falcate braced with CF top and bottom of all braces. Back is radially braced.
Other images of the build/bracing can be seen here: http://milsomguitars.weebly.com/heathers-parlour.html
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- Blackwood
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Re: Cherry and WRC Parlour sprectra question
Do you think the 209 Hz is the top? With a parlor I suspect the 239 Hz is the top resonance T(1,1)2 before the bridge and strings. Also the 239 Hz peak is taller than the 209 Hz. I wonder if the back resonance is lower than the top. Nice looking guitar.
- Francis
- Myrtle
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Re: Cherry and WRC Parlour sprectra question
John - I'm not sure - the back before closing didn't sound lower than the back - though I dodn't take any spectra at that stage.
- lamanoditrento
- Blackwood
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- Francis
- Myrtle
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Re: Cherry and WRC Parlour sprectra question
Phone app is: Spectrum Analyze (found a link on this site - somewhere...)
Few more traces with a narrower range:
Red traces are front plate tapped at bridge position - yellow on back plate opposite the bridge position.
This is just finger tapping on the different points so db levels have changed each time...
Few more traces with a narrower range:
Red traces are front plate tapped at bridge position - yellow on back plate opposite the bridge position.
This is just finger tapping on the different points so db levels have changed each time...
Re: Cherry and WRC Parlour sprectra question
I just did a quick tap test on my parlour with results as follows:johnparchem wrote:Do you think the 209 Hz is the top? With a parlor I suspect the 239 Hz is the top resonance T(1,1)2 before the bridge and strings. Also the 239 Hz peak is taller than the 209 Hz. I wonder if the back resonance is lower than the top. Nice looking guitar.
T(1,1)1 - 110.5Hz
T(1,1)2 - 207Hz
T(1,1)3 - (back) 269.6Hz (top not coupling with back at this stage).
Martin
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- Blackwood
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Re: Cherry and WRC Parlour sprectra question
Is that stung up or just closed?kiwigeo wrote:I just did a quick tap test on my parlour with results as follows:johnparchem wrote:Do you think the 209 Hz is the top? With a parlor I suspect the 239 Hz is the top resonance T(1,1)2 before the bridge and strings. Also the 239 Hz peak is taller than the 209 Hz. I wonder if the back resonance is lower than the top. Nice looking guitar.
T(1,1)1 - 110.5Hz
T(1,1)2 - 207Hz
T(1,1)3 - (back) 269.6Hz (top not coupling with back at this stage).
Re: Cherry and WRC Parlour sprectra question
Bridge on strung up with strings damped.johnparchem wrote:Is that stung up or just closed?kiwigeo wrote:I just did a quick tap test on my parlour with results as follows:johnparchem wrote:Do you think the 209 Hz is the top? With a parlor I suspect the 239 Hz is the top resonance T(1,1)2 before the bridge and strings. Also the 239 Hz peak is taller than the 209 Hz. I wonder if the back resonance is lower than the top. Nice looking guitar.
T(1,1)1 - 110.5Hz
T(1,1)2 - 207Hz
T(1,1)3 - (back) 269.6Hz (top not coupling with back at this stage).
Martin
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- Blackwood
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Re: Cherry and WRC Parlour sprectra question
I have found as much as a 20 Hz drop after gluing on the bridge and putting strings on a steel string. His 209 Hz is certainly in the range for a small body guitar for the T(1,1)2
- Steve.Toscano
- Blackwood
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Re: Cherry and WRC Parlour sprectra question
Did you close over those string holes in the top when tapping? One of your peaks could be an air freq coming from those holes if the phone is pointed at them...
Also i find i dont get good results with finger tapping, for a quick and easy tapper try an eraser on a skewer, just round over one end of the eraser to very blunt point.
Also i find i dont get good results with finger tapping, for a quick and easy tapper try an eraser on a skewer, just round over one end of the eraser to very blunt point.
Re: Cherry and WRC Parlour sprectra question
Upper bout soundport is going to raise the air resonance and consequently the others.
- Francis
- Myrtle
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Re: Cherry and WRC Parlour sprectra question
Many thanks for the responses guys. The bridge pin holes were open and the sound-port too. So will have another go closing these and make a 'tapper' rather than the Mk 1 finger tip.
TBC...
TBC...
- Francis
- Myrtle
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Re: Cherry and WRC Parlour sprectra question
Following the above comments I've closed the bridge pin and sound port holes, made a tapper and re-recorded sets of data at shorter scale ranges to get more precise peaks -
The upper frequencies (209.95 and 236.87 Hz) have remained the same, the lower frequency has dropped from 123.82 to 118.43 Hz with the aperture closures.
Need to go away and read more from 'the book' to get a better understanding of these graphics.
Cheers Guys
The upper frequencies (209.95 and 236.87 Hz) have remained the same, the lower frequency has dropped from 123.82 to 118.43 Hz with the aperture closures.
Need to go away and read more from 'the book' to get a better understanding of these graphics.
Cheers Guys
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- Blackwood
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Re: Cherry and WRC Parlour sprectra question
That looks more normal, so it looks like your Main top is at 230 Hz, after it is bound with a bridge and strung up it may be around 210. That is where my small guitars end up. I do see that 209 ish peak in the white back tap test.
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