Search found 1494 matches

by Trevor Gore
Mon Feb 03, 2020 9:52 am
Forum: Instrument Builders Forum
Topic: Qualities of Spruce
Replies: 17
Views: 1335

Re: Qualities of Spruce

Thanks, DaveO. ...But I have noticed slightly (non significantly) higher E long results comparing thin bracewood to wider soundboard stock, when comparing population with a simple t-test. My charts are from data made up primarily of sound board samples planed to ~ 4mm thick and measured for the elas...
by Trevor Gore
Sun Feb 02, 2020 11:35 pm
Forum: Instrument Builders Forum
Topic: Stain on soundboard
Replies: 11
Views: 857

Re: Stain on soundboard

Bruce, I suspect that kind of staining came from the gig bag. Some time back a manufacturer was offering a "protective wrap" for a guitar for inside the case and it left marks like that, but fortunately it wasn't on one of my guitars. Whatever it was came out of the wrap and into the finish, though ...
by Trevor Gore
Thu Jan 30, 2020 10:18 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: High frequencies
Replies: 2
Views: 426

Re: High frequencies

I was always lead to believe that anything above 1K really isn't worth worrying about. Happy to be proved wrong. Trevor?? It's certainly difficult to target specific modes of vibration up beyond 1k Hz, so it's down to doing things that support high frequencies generally, like keeping monopole mobil...
by Trevor Gore
Thu Jan 30, 2020 9:06 am
Forum: Instrument Builders Forum
Topic: Qualities of Spruce
Replies: 17
Views: 1335

Re: Qualities of Spruce

Thanks for posting that DaveO. I have a similar chart with a tighter spread, which just indicates that a lot of selection has gone into the wood before I measure it (so not a random sample). Also, the regression line is lower down the page in my results, indicating lower measured E long values. I pr...
by Trevor Gore
Fri Jan 03, 2020 8:44 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: VA plots for tap test on plates
Replies: 13
Views: 1557

Re: VA plots for tap test on plates

Were any of the panels not flat enough?
by Trevor Gore
Wed Jan 01, 2020 12:06 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: VA plots for tap test on plates
Replies: 13
Views: 1557

Re: VA plots for tap test on plates

Fdiag should be an easy one to get, assuming you have the VA set up right. Hold the panel in the middle of the long side edge, tap lightly on a lower corner with the mic right behind the corner you tap. Often the problem is due to tapping too hard or not putting the mic where it can "hear" the vibes.
by Trevor Gore
Tue Dec 31, 2019 9:01 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Latest build final tap results
Replies: 1
Views: 316

Re: Latest build final tap results

That looks close enough to ideal to leave it as is. Well done, Chris!
by Trevor Gore
Mon Dec 23, 2019 1:03 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Unusual Panal Size
Replies: 6
Views: 681

Re: Unusual Panal Size

Sorry about the typo. Should have been p 4.39.
by Trevor Gore
Mon Dec 23, 2019 8:38 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Unusual Panal Size
Replies: 6
Views: 681

Re: Unusual Panal Size

For non-rectangular pieces, e.g. a rectangle with a corner cut off, choose a part of the panel that is rectangular and do a three point bend test on that part. Page 4.30 Design.
by Trevor Gore
Thu Dec 05, 2019 7:38 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Spectrum change with age
Replies: 5
Views: 941

Re: Spectrum change with age

I've found that if I use "old" wood (that I've had for at least 5 years), the guitar seems to get louder with age but the spectrum remains much the same. If I use "new" wood, cut and dried for less than 2 years, the guitar gets stiffer as it ages and whilst the shape of the spectrum remains recognis...
by Trevor Gore
Fri Nov 22, 2019 7:57 am
Forum: Instrument Builders Forum
Topic: Searching for Carbon Fiber for a Falcate Guitar Build
Replies: 4
Views: 1018

Re: Searching for Carbon Fiber for a Falcate Guitar Build

These guys keep changing their name but are still in the same business and is where I've bought the CF products called for in the books. The cloth (1m wide) is much more economical to buy than tape (or was!). Give them a call and see if they still stock CF. https://allnex-brookvale.business.site/
by Trevor Gore
Wed Nov 20, 2019 9:45 am
Forum: Instrument Builders Forum
Topic: packaging tape for binding
Replies: 12
Views: 1692

Re: packaging tape for binding

I am looking for a source of the reinforced packaging tape to use for binding work...any recommendations? What are you using and do you find that the tape is strong enough by itself or do you still bind with stretchy cord or rubber as well? Cheers! Ross I use the two-way filament tape from these gu...
by Trevor Gore
Mon Nov 18, 2019 11:25 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Design Book
Replies: 1
Views: 551

Re: Design Book

Thanks for the kind words, Tom.
by Trevor Gore
Wed Nov 06, 2019 9:48 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Bridge Rotation at 2.3deg
Replies: 15
Views: 2483

Re: Bridge Rotation at 2.3deg

John, do the before and after tap responses tell you any more about what changes happened?
by Trevor Gore
Mon Nov 04, 2019 9:24 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Spectrum results
Replies: 3
Views: 1175

Re: Spectrum results

Good to hear it all worked out. Well done!
by Trevor Gore
Sun Nov 03, 2019 10:03 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: My Second Build
Replies: 15
Views: 2626

Re: My Second Build

Your bridge looks the same size as mine (presumably made off the book drawings). Mine stay on! Them peeling off is as much about the bridge plate design as it is about the glue area, and you have the standard falcate bridge plate.
by Trevor Gore
Sat Nov 02, 2019 10:32 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Spectrum results
Replies: 3
Views: 1175

Re: Spectrum results

95,170, 214 is a great result. Carving the back brace to reduce the T(1,1)1 and T(1,1)2 sufficiently will bring the T(1,1)3 down way too far and cause acoustics problems that you don't need because you no longer have the 4 semitone separation. Stringing up will possibly drop the T(1,1)2 a little bec...
by Trevor Gore
Mon Oct 28, 2019 8:25 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Bridge Rotation at 2.3deg
Replies: 15
Views: 2483

Re: Bridge Rotation at 2.3deg

I haven't spoken to Charles about a future class. Maybe an idea for another occasion!
by Trevor Gore
Sun Oct 27, 2019 10:14 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Bridge Rotation at 2.3deg
Replies: 15
Views: 2483

Re: Bridge Rotation at 2.3deg

Eric, there's the possibility of another class at Robbie's 10/11/12 Jul 2020. Please contact Robbie if you're interested.
by Trevor Gore
Sat Oct 26, 2019 10:30 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Bridge Rotation at 2.3deg
Replies: 15
Views: 2483

Re: Bridge Rotation at 2.3deg

My rotation ended up at 1.3 degrees... Let me refer you to this post from a while back: http://www.anzlf.com/viewtopic.php?f=33&t=6321&p=71613#p71613 Don't get too hung up on the bridge rotation if the modal frequencies and the monopole mobility are right. However, if the modal frequecnies are too ...
by Trevor Gore
Sat Oct 26, 2019 10:09 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: saddle location
Replies: 4
Views: 878

Re: saddle location

The problem I find is that leaving only1.2mm on the back of the saddle, 6th string, tends to lead to too much crushing and wear on the saddle, especially if Tusq is used. Obviously this is also a problem when using the traditional narrow saddle. As the contact point only ever moves forward as the br...
by Trevor Gore
Fri Oct 25, 2019 4:01 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: saddle location
Replies: 4
Views: 878

Re: saddle location

What am I missing? ...that I say in the last two lines of para 2 Section 20.3.2 (both editions) that you work it out for the string that has the shortest distance (typically the first string). The longest distance is typically ~ 3mm more, so that gives you ~2mm "land" of saddle on a 5mm saddle for ...
by Trevor Gore
Fri Oct 25, 2019 3:33 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Bridge Rotation at 2.3deg
Replies: 15
Views: 2483

Re: Bridge Rotation at 2.3deg

John, I've seen some seriously "roller-coaster" tops that have sounded fine, so that in and of itself doesn't appear to be sufficient criteria for less-than-best sound quality. Similarly, "print through" of the bracing pattern is pretty normal on highly responsive guitars. One of the things that I'v...
by Trevor Gore
Wed Oct 23, 2019 8:22 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: My Second Build
Replies: 15
Views: 2626

Re: My Second Build

DavidS wrote:
Tue Oct 22, 2019 8:09 pm
I am trying to figure out whether I am going to be able to achieve a finished T(1,1)2 close enough to 170Hz given I am starting at 180hz closed box.
Provided you remove very little wood on binding and clean-up and use a very low mass bridge (< 15 gms), you should be close.
by Trevor Gore
Sun Oct 20, 2019 10:12 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Paulownia fas bridge material?
Replies: 5
Views: 998

Re: Paulownia fas bridge material?

The Paulownia I've had is only one step removed from balsa and quite soft. I doubt it would hold up using the designs in the books. With some very cunning design work it might work, but I suspect some pretty complicated manufacturing would be required.