Parlour Build frequencies.

[colin north]

Got the box closed up on a parlour build and first indications are frequencies of 124, 249. and 265.
No edge thinning has been done.
Dimensions are 460 x 310 mm.
Top is 2,4mm eurospruce with 6.5mm x 13mm scalloped X braces and back frequency could be taken up without too much trouble if necessary to achieve targets, as can binding th soundhole to take body frequency down.
What would be good target frequencies?
100/190/240 tempt me are the highest "set" in the Book for a not quite so small body, but might involve thinning top/reducing brace height to the point of imminent collapse.

[Trevor Gore]

I've not been very interested in small SS instruments, so I don't have a lot of data for parlour sized guitars. However, I have a tap response for a Martin 0-18 (which I cannot for the life of me recall; files dated 2008), 13.5" lower bout (343mm) which tapped out at 103, 182, 228.

I make a small body classical around the same size and typically go for 100, 190, 240, but from where you are it will be hard to get down to those numbers on such a small guitar. You might try for 113, 214 and leave the back where it falls without further work.

Jim (Darwin Strings) has built a few parlours so might care to add some more info. Here's some data from one of his.

[luke_lee]

Hi Colin,

I finished a parlour last year, 480 long and 332 wide lower bout. X braced sitka, non scalloped.

Boxed up I got 117, 232, 279 after thinning the edges i got 114, 226, 278

Finished guitar with bridge 116,203, back not sure.

The frequencies were not where I wanted them and the G note on the bass E string had no sustain.
I added a tornavoz which is removable, it is 58mm deep and got to 90, 193, (260 & 276 split peak) I think it sounds much better for it.

The sound hole diameter was 95mm I think it was too large, I will use a smaller diameter next time.

Hope this helps Luke.

[Trevor Gore]

Nice work, Luke.

How did you make your tornavoz?

[soundshooter]

I posted some photos of a falcate parlor in the gallerie.
Here is the spectro of the finished guitar

113 190 238

Here it is with the box freshly closed.

122 219

Sorry there not the same size/sacale but it still gives you an idea how things developed. Good luck
Frank

[colin north]

Thanks for your input guys. Nice parlors!!
Mine looks very plain in such company.
Since my post, I've thinned the top to 2.0 mm at the bridge area and 1.8 mm round the lower bout (it's really stiff and quite heavy Eurospruce) and have fitted the neck to take a few taps
I'm at 117, 227 and 262 Hz, and with the size I don't think I can expect to get down much more.

Parlour Specrogram.jpg (78.78 KiB) Viewed 22738 times

Looks reasonably lively.
X braced, so bridge (ABW, maybe around 25g) should bring the top down to around 217, see how it goes with the rest.
May have to bind the soundhole to bring the body frequency down a bit, as weighting the top and back (experimentally) gives me 115, 214 and 252(?).

[luke_lee]

I made my tornavoz out of ply, laminate and PVC pipe it has two parts and I sprayed it black.
I took some photos of the prototype to show how it is made/installed.

Photo 1 is the two parts and a sketch/section to see the profile of the outer ring.

Photo 2 is the outer ring install

Photo 3 is the inner tube sliding through the soundhole, I used the length of this to adjust/tune the frequency drop of T1 which also changed T2.

Photo 4 is the inner tube in its final position, a rebate in the outer ring helps locate the inner tube. On the final tornavoz I used some small dowels to hold the inner tube in position.

[Trevor Gore]

Thanks for posting that, Luke. Neat!

[DarwinStrings]

Sorry I have not been around much and just found this.

My first one I ended up with 118Hz air and 202 (none live back) I can still adjust it with side mass but am not bothered. On the second I dropped the brace size with a slightly deeper body plus live back and managed 107 air 180 top and 224 back. Pretty happy with both but hoping to get that air down on number three to 100 and like Trevors classical I might leave the top at 190 with 240 back. I reckon after a few more variation I will then decided what I like best for this sized guitar, 320mm lower bout 460 length and 14 fret to body steel string.

Jim

Edit, there is a sound clip of the first one in the Gallery.

[printer2]

Just got Visual Analyser up and running with a usb mic and low and behold, it works. Looking for guidance on small guitars and a thread about parlors seems to fit like hand in glove. This is the first guitar I built out of a cedar fence board for a top and pine for the sides and backs. Not perfect but it does not sound too bad.



I am just starting on the tuning section of design and build but have other priorities at the moment so I do not know too much the responses. Hopefully in a week or two I can get back at it. Just wanted to give the frequencies I have at the moment. The box is 16" long, 13" lower bout, I got 122, 218, 260.

[kiwigeo]

Watching this thread with interest...am just starting a Parlour build. Not sure whether to go falcate or cross braced at this stage.

[printer2]

I really should not have been doing this as I have way more important things to do. Well, guess that tells you a little of the kind of guy I am. I built that pine guitar last year and while surfacing the tops, sides and backs along with bending them I made up some extras. Once I built the first one I was confident enough to build a guitar with better wood. But what do I do with the cedar and pine I made into sets? Hate to just throw them away but not worth spending a lot of effort on. What the heck, let's use them to experiment with. Forgive some of the less than perfect construction. These were meant to be disposable.

Other than two of the tops being cedar and two pine I made them more or less identical with the same bracing.



Did different backs though. Starting from the left #1, the lower bout has thicker braces laid down as compared to #3 which has the lower bout braces vertical. Pine tops, #2 has a three piece back and #4 has a double thickness back also with laid down braces. Why? Other than the three piece back, heck why not?



To even throw more into the mix, had some sides that did not turn out that well, used them and doubled up the sides on #1 and #2.



Had some fun painting one with spray cans and got a nice sunburst. Shame the paint came out spiting a little and had little blobs of paint all over. Decided to scrape them down and going to have the guitar looking a little distressed. Should have dusted it first for the picture though.



Now back to this thread. I used my binding cutting body holder to support the bodies and took some measurements of these guitars. No bridge on them yet so the numbers will change yet. Getting farther in the book, getting the concepts but what numbers and where still has to sink in. Top is the top resonance without the sound hole.

Pine double thickness back (#4)
132, 256, , top 241, back 287

Pine three piece back (#2)
124, 241, 300, top 234, back 281

Cedar flat back brace (#1)
123, 233, , top 243, back 247

Cedar tall back brace (#3)
127, 245, 428, top 234, back 221

Do not know if any of this will be useful but as I get further along in the book and get the guitars completed I will take some more measurements. Not sure how relevant these will be as they have softwood sides and backs as compared to guitars with hardwood. I plan on making one or two of the same size guitars with hardwood b&s's so maybe we can compare them with these also. I plan on making a few more parlors of a different shape so maybe even more numbers to compare. Would be great if someone could get some measurements off some really good parlors so we know what makes a good one or not.

I just thought, should I have put this in a separate thread or in this one? I wasn't really planing to go through the construction of these so I thought the measurement side of it fits more in here.

[printer2]

Numbers looked wrong on #1 so I redid it.

Cedar flat back brace (#1)
123, 275, , top 241, back 247

[kiwigeo]

Raw boxed up frequencies for my falcate parlour build (Scott Antare plan).

T(1,1)1 - 121Hz
T(1,1)2 - 213Hz
T(1,1)3 - 264Hz

[kiwigeo]

Raw boxed up frequencies for my falcate parlour build (Scott Antare plan).

T(1,1)1 - 121Hz
T(1,1)2 - 213Hz
T(1,1)3 - 264Hz

Re-did tap testing on the parlour today after thinning of top. Pics of the build will be posted once I get a chance.

T(1,1)1 - 112Hz
T(1,1)2 - 203Hz
T(1,1)3 - 269Hz

Once bridge is on Id expect T(1,1)2 to drop a Hz or two. Final frequencies look theyll be similar to Jims figures.