Author Topic: Why 30.75"? (Read 344 times)

dnburgess · « **on:** September 24, 2004, 10:11:51 PM »

Is there a special reason why 30.75 was chosen as the scale length for short scale instruments, instead of a round number - 30 or 31?

kungfusheriff · « **Reply #1 on:** September 25, 2004, 02:32:52 AM »

Guild Starfire basses, which Alembic started out customizing in San Fran, were 30.75.

poor_nigel · « **Reply #2 on:** September 25, 2004, 02:59:26 AM »

My old Les Paul is 30.75 and so is my 65 EBO (single humbucker, SG looking bass). I wonder if Leo Fender's string length tests were referenced when these companies decided on their short-scale length and is 30.75 the industry 'standard' for short-scale basses? I am actually quite curious about this subject now, though I doubt I will ever buy a length under 34 inches these days.

811952 · « **Reply #3 on:** September 25, 2004, 09:35:40 AM »

I am inclined to suspect that a 30.75 scale can use the same fretting template as either a 34 bass or perhaps one of the guitar scales. Just a guess - I haven't actually taken the 3 minute to do the measurements..
John

somatic · « **Reply #4 on:** September 27, 2004, 02:57:07 AM »

Because it's 3/4 of the 41 scale a lot of uprights use?

dfung60 · « **Reply #5 on:** September 30, 2004, 12:06:34 AM »

811952's guess is correct, I believe. A medium scale bass is setup like a 34 scale with the nut moved to where the first fret would be; a short scale bass is set up where the nut is moved to where the second fret in 34 would be. By doing it this way, you can use the same fretline template (well, you do have to add one or two more frets at the high end).

These shorter scale length conventions predate Alembic - as cited above, Gibson was using 30.75 back in the 60's if not the 50's. Alembic in fact has always allowed you to select any scale length that you like - they're not afraid of calculating and cutting fret positions to your liking.

somatic · « **Reply #6 on:** October 01, 2004, 12:30:11 AM »

A medium scale bass is setup like a 34 scale with the nut moved to where the first fret would be; a short scale bass is set up where the nut is moved to where the second fret in 34 would be. By doing it this way, you can use the same fretline template (well, you do have to add one or two more frets at the high end).

That doesn't calc out quite the same on the calculator I have, and enough of a difference to make me reluctant to use that method myself without someone experienced at fretting and intonating accurately this way saying it works fine. The errors get worse the higher the fret. It does seem logical though.
Visit Fret Slot Spacing Calculator and plug in the numbers (BTW, 30.75 = 781.05mm). I only compared 34 and 30.75

Maybe someone from Alembic could comment on this.

(Message edited by somatic on October 01, 2004)

poor_nigel · « **Reply #7 on:** October 01, 2004, 12:56:39 AM »

Actually, I held up a 30.75 scale to a 34 scale, as noted and the higher frets do not match. They are a bit off. It is close though. At least we know where the 34 scale came from. Thanks Leo!

811952 · « **Reply #8 on:** October 01, 2004, 06:20:03 AM »

...And I thought I was on a roll! C'est la vie...
John

son_of_magni · « **Reply #9 on:** October 01, 2004, 10:46:00 AM »

I actually tried to check John's theory but then I looked at my basses and doh, no frets!

mica · « **Reply #10 on:** October 01, 2004, 11:04:18 AM »

Our standard scale lengths are based on established standard scale lengths. Since basses and guitars were made for many years before we started, it makes sense to build them in sizes that players are familiar with. Of course, if you need something different, we do offer custom scale lengths as David mentioned.

The placement of the frets is calculated as the twelfth root of 2. Each scale length will have the frets in a different position. All the frets are closer together on shorter scale lengths and spread out on extended scales.

dnburgess · « **Reply #11 on:** October 01, 2004, 10:03:53 PM »

Using the same fretting template theory with 34 inches as the reference point, would imply a scale length of 32.09 inches by cutting off the first fret, which is pretty close to 32 medium scale. So far so good.

But taking off another fret gives 30.29 inches - a long way off standard short scale.

Going the other way and adding a fret to a 34 bass gives a scale length of 36.02 inches. Close enough to extra long scale.

David B.

bigredbass · « **Reply #12 on:** October 02, 2004, 10:40:58 PM »

On Yamaha's BB basses from the 70s-80s, they quoted a 33 7/8 (!?!) scale. I've often wondered if this was their invention or some conversion from centimeters.

Any ideas?

J o e y

joram · « **Reply #13 on:** October 03, 2004, 03:41:11 PM »

33 7/8 is approx. 86 cm (1 is 2.54 cm. 33 7/8*2.54=86,0425. I'm pretty sure it's a conversion. Vigier uses the same, and quotes it as 33.8.

Joram

kungfusheriff · « **Reply #14 on:** October 03, 2004, 05:09:02 PM »

Correctamundo, likely based on the Rickenbacker scale, but that's a question for another forum