Search found 1439 matches

by Trevor Gore
Sun Jul 14, 2019 3:20 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: opinion about my frequency spectra
Replies: 10
Views: 356

Re: opinion about my frequency spectra

You write that when you talk about characteristic frequencies T(1,1)1, T(1,1)2 and T(1,1)3 you mean the fully coupled frequencies. So I have to look at the unplugged spectrum. Yes. The "air" and back peaks easy to identify because they disappear in the plugged spectrum. In the unplugged spectrum I ...
by Trevor Gore
Sun Jul 14, 2019 2:55 pm
Forum: Instrument Builders Forum
Topic: What wiring for Trevor Gore style side bender?
Replies: 7
Views: 266

Re: What wiring for Trevor Gore style side bender?

When I built my side bender it was really hard to find ceramic globe holders for a decent price. What I ended up doing was buying 3 sets of security lights (with photo/movements sensors etc.) which had ceramic globe holders for PAR 38 globes (rated at 250w, iirc). This (crazily) was a lot cheaper op...
by Trevor Gore
Fri Jul 12, 2019 2:35 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: opinion about my frequency spectra
Replies: 10
Views: 356

Re: opinion about my frequency spectra

As I interpret those charts I see a T(1,1)1 at ~100Hz, a T(1,1)2 at ~167Hz and a T(1,1)3 at ~215Hz. Stiffening the back will repel the top down less, hopefully bringing it up to ~170Hz. Alternatively, a lower mass bridge would bring the T(1,1)2 up to ~170Hz and by repulsion push up the T(1,1)3 a bit...
by Trevor Gore
Thu Jul 11, 2019 1:12 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: opinion about my frequency spectra
Replies: 10
Views: 356

Re: opinion about my frequency spectra

Btw. just to be sure: when you talk about the target frequencies you talk about the values I determined by comparing the spectra with and without soundhole plug and not the peak positions in the "unplugged" spectrum? When I reference the T(1,1)1 and T(1,1)2 etc. I am always referring to the fully c...
by Trevor Gore
Tue Jul 09, 2019 2:53 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: opinion about my frequency spectra
Replies: 10
Views: 356

Re: opinion about my frequency spectra

I think your interpretations are all correct, Jurgen. Regarding the "shakey" tap on Audacity, I don't know what that specifically means in Audacity. However, if you get a plot like that in VA it means you captured two taps in one buffer (rather than just the one). Regarding the spectrum plots, if it...
by Trevor Gore
Tue Jul 02, 2019 8:58 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Flexural rigidity & Co
Replies: 3
Views: 338

Re: Flexural rigidity & Co

With the MOR would guess one needs a good statistic to get a meaningful result. As I´m not a professional luthier with unlimited supply of material I think I will have to take cut a piece from the wood I want to use for braces and do the test every time again. Unless you're using unusual materials ...
by Trevor Gore
Mon Jul 01, 2019 9:32 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Flexural rigidity & Co
Replies: 3
Views: 338

Re: Flexural rigidity & Co

1. When entering the values for a falcate steel string taken from the plans I have an effective soundboard width of 345mm in 50mm distance to the bridge (btw. I assume I start measuring in front of the bridge and not at the position of the saddle), the cross section in this case shows 4 braces with...
by Trevor Gore
Wed Jun 12, 2019 7:52 pm
Forum: Instrument Builders Forum
Topic: travelling with several guitars?
Replies: 7
Views: 699

Re: travelling with several guitars?

Just de-tuning. Don't chock the guitar so tight it won't move in the case, otherwise it decelerates at the same rate the case decelerates at, if it's dropped. The Hiscox cases have huge crush strength, so that's never a problem, but deceleration damage possibly could be.
by Trevor Gore
Wed Jun 12, 2019 8:09 am
Forum: Instrument Builders Forum
Topic: travelling with several guitars?
Replies: 7
Views: 699

Re: travelling with several guitars?

Rod, I've traveled all over (US, Europe, Asia) with guitars in Hiscox cases, including numerous times with United, all with guitars as checked baggage. No problems so far. However, flying with multiple guitars on a single passenger ticket will likely cost a lot in baggage charges, so check that out....
by Trevor Gore
Sat May 11, 2019 6:24 pm
Forum: Instrument Builders Forum
Topic: Fine Tools Australia
Replies: 3
Views: 787

Re: Fine Tools Australia

Thank you gentlemen.
by Trevor Gore
Fri May 10, 2019 4:06 pm
Forum: Instrument Builders Forum
Topic: Fine Tools Australia
Replies: 3
Views: 787

Fine Tools Australia

Does anyone have a phone number for these guys (Melbourne based)?

https://www.finetools.com.au/

They don't seem to respond to email.

Thanks.
by Trevor Gore
Tue May 07, 2019 7:08 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Veritas scraper plane in lieu of high angle plane
Replies: 3
Views: 465

Re: Veritas scraper plane in lieu of high angle plane

To me (at least) high angle planes and scraper planes are very different beasts. I don't own a scraper plane (but I use card scrapers), I have 2 high angle planes and can configure 2 other planes as high angle planes. I find that if I can't do it (whatever "it" happens to be) with a high angle plane...
by Trevor Gore
Sun May 05, 2019 11:08 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Diamond stones for sharpening
Replies: 2
Views: 359

Re: Diamond stones for sharpening

DMT brand diamond "stones". The ones shown in the book have been superseded. I think shorter ones are available but not the ones in the book. The page I linked to has the alternative Duosharp stones. I have the blue and the green grades. They start very aggressive, but settle quickly. I've had mine...
by Trevor Gore
Fri May 03, 2019 12:21 am
Forum: Instrument Builders Forum
Topic: Slow neck carving
Replies: 21
Views: 2071

Re: Slow neck carving

No more than a couple of hours for me using the book procedure, and mainly spoke shaves, of which I have a few. I certainly wouldn't be game to use a draw knife on the figured wood I often use! "Normal" spoke shaves work well for removing the bulk of the wood. I use a high angle spoke shave on figur...
by Trevor Gore
Thu May 02, 2019 11:26 pm
Forum: Instrument Builders Forum
Topic: Luthier Sessions #2 - Hand Planing for Luthiers, by Trevor Gore
Replies: 3
Views: 733

Re: Luthier Sessions #2 - Hand Planing for Luthiers, by Trevor Gore

There's no heavy maths like the modal tuning course Martin, but there is some precision set-up for those who want precision results!
by Trevor Gore
Wed May 01, 2019 9:03 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: dB levels question?
Replies: 8
Views: 791

Re: dB levels question?

Well done, Chris! The numbers look good, but how does it sound?
by Trevor Gore
Tue Apr 30, 2019 8:40 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: dB levels question?
Replies: 8
Views: 791

Re: dB levels question?

Do the Books discuss varying dB levels in regard to the various T1, T2, T3s? All I say is that the dB level is uncalibrated. That is due to the uncontrolled tap strength and the recording environment (mic response, mic position, signal strength, room reflections, etc. etc.). To get calibrated dB le...
by Trevor Gore
Mon Apr 29, 2019 10:27 am
Forum: Instrument Builders Forum
Topic: Modal Tuning Course in Melbourne, June 2019
Replies: 0
Views: 394

Modal Tuning Course in Melbourne, June 2019

I will be running one of my 3 day Modal Tuning courses again in Melbourne in June. The course has proved to be very popular with Victorians! What we will cover: • How strings drive your guitar • Visualising and understanding modes of vibration • Relating modes of vibration to guitar frequency respon...
by Trevor Gore
Tue Apr 16, 2019 9:06 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Just closed the box - strategy?
Replies: 15
Views: 1624

Re: Just closed the box - strategy?

As long as you're having fun... :D
by Trevor Gore
Mon Apr 15, 2019 9:34 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Just closed the box - strategy?
Replies: 15
Views: 1624

Re: Just closed the box - strategy?

The audience will likely miss out on some bass response, but the player might not because the port will act as a "monitor" and so the player may hear a stronger bass. Maybe.
by Trevor Gore
Mon Apr 15, 2019 9:35 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Just closed the box - strategy?
Replies: 15
Views: 1624

Re: Just closed the box - strategy?

gerryt wrote:
Mon Apr 15, 2019 7:14 am
What I don't understand is why my T(1,1)1 is so high - currently at 109Hz
Well, don't forget the effect of the sound port. Depending on how big and whether you compensated by reducing the sound hole size, could be worth 5-10 Hz.
by Trevor Gore
Sun Apr 14, 2019 10:49 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Just closed the box - strategy?
Replies: 15
Views: 1624

Re: Just closed the box - strategy?

Taping bridges on doesn't tell you a whole lot. You add the mass but not the stiffness. The effect on the T(1,1)2 of adding bridges is shown in Fig. 4.6-3 (Design). For the T(1,1)1, adding the bridge typically raises its frequency a small amount on my guitars. Adding the stiffness reduces the amount...
by Trevor Gore
Sat Apr 13, 2019 5:20 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Just closed the box - strategy?
Replies: 15
Views: 1624

Re: Just closed the box - strategy?

You could "blind bind" the fretboard - bind in the same wood as the fretboard, no purfling lines. That covers the tangs. Leave the end unbound.

If you thicknessed the back according to the formula, working the back brace should get you there.
by Trevor Gore
Sat Apr 13, 2019 10:28 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Just closed the box - strategy?
Replies: 15
Views: 1624

Re: Just closed the box - strategy?

The plots don't look much like mine but I think we can work with them. It looks like the T(1,1)1 is close to 113 Hz and the T(1,1)2 is close to 200Hz. The B(1,1) is at 238Hz, which implies that the T(1,1)3 would be around around 240Hz or a couple of Hz higher, if it were there. I guess you're using ...
by Trevor Gore
Fri Apr 12, 2019 9:14 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Just closed the box - strategy?
Replies: 15
Views: 1624

Re: Just closed the box - strategy?

Gerry,

Check out the last line of the last paragraph, p AI-3, (Design) for guitar holding instructions whilst tapping, then post another tap plot.

Thanks, T.