Hello folks,
I currently acquired a vintage Celestion G12-65 (15 ohm) guitar speaker (manufactured in January 25, 1982) in perfect condition.
Here are the reissue version's specs from Celestion
-----------------------------------------------------------------
Fs - 79 Hz (Their main page says 85 Hz? Does it make a big difference)
Re - 11.8 Ohm
Qms - 10.67
Qts - 0.61
Qes - 0.65
Cms - 0.13 mm/N
Vas - 51.4 lt
Le@1kHz - 0.78 mH
Pe: 65 Watts
Now, from what I read, before designing a cab I need to decide the Qtc of the cabinet. It's said that the best value for a guitar cabinet should be between 0.707 and 1.0. Let's say Qtc = 0.71
Also, again from what I read the F3 value should be below the lowest fundamental which is 73 Hz since I play in drop D tuning from time to time (But mostly I use standard E tuning, so should I chose 81 Hz?)
Another thing that I want is a good low frequency response so I choose to go with sealed back design without any ports or damping materials.
The problem occurs when I give all these information to HT Audio software to calculate the box dimensions...
Here are the steps that I took and the given error:
I appreciate all the help
Thanks
I currently acquired a vintage Celestion G12-65 (15 ohm) guitar speaker (manufactured in January 25, 1982) in perfect condition.
Here are the reissue version's specs from Celestion
-----------------------------------------------------------------
Fs - 79 Hz (Their main page says 85 Hz? Does it make a big difference)
Re - 11.8 Ohm
Qms - 10.67
Qts - 0.61
Qes - 0.65
Cms - 0.13 mm/N
Vas - 51.4 lt
Le@1kHz - 0.78 mH
Pe: 65 Watts
Now, from what I read, before designing a cab I need to decide the Qtc of the cabinet. It's said that the best value for a guitar cabinet should be between 0.707 and 1.0. Let's say Qtc = 0.71
Also, again from what I read the F3 value should be below the lowest fundamental which is 73 Hz since I play in drop D tuning from time to time (But mostly I use standard E tuning, so should I chose 81 Hz?)
Another thing that I want is a good low frequency response so I choose to go with sealed back design without any ports or damping materials.
The problem occurs when I give all these information to HT Audio software to calculate the box dimensions...
Here are the steps that I took and the given error:
I appreciate all the help
Thanks
Hi,
Your F3 is too low as the program states.
With Vas = nearly 2cuft and Fs ~ 80Hz and Qts = ~ 0.6 you do not
have a driver particularly suited to a sealed box. I'd would say it
will work quite well open backed with a valve guitar amplifier.
THe assumption here is the valve amplifer has significant output
impedance and this will fatten the open backed response.
A closed box is doable with a transistor amplifier, practicality suggests
a stuffed box around 1cuft, though an unstuffed box will be livelier.
Note that reproducing fundamentals accurately is not necessary.
/sreten.
Your F3 is too low as the program states.
With Vas = nearly 2cuft and Fs ~ 80Hz and Qts = ~ 0.6 you do not
have a driver particularly suited to a sealed box. I'd would say it
will work quite well open backed with a valve guitar amplifier.
THe assumption here is the valve amplifer has significant output
impedance and this will fatten the open backed response.
A closed box is doable with a transistor amplifier, practicality suggests
a stuffed box around 1cuft, though an unstuffed box will be livelier.
Note that reproducing fundamentals accurately is not necessary.
/sreten.
I heard that these speakers sound quite bright with an open backed cabinet so I though I might lower it with a sealed box. I purchased the wrong speaker after all 
http://reviews.harmony-central.com/reviews/Guitar+Amp/product/Celestion/G12-65/10/1
Hi,
Open backed or closed I think they will be fine. Most guitar speakers
do not follow "hi-fi" bass alignments, I would not worry about it.
They were originally designed for sealed 4x12's, so go sealed.
/sreten.
Hi,
Open backed or closed I think they will be fine. Most guitar speakers
do not follow "hi-fi" bass alignments, I would not worry about it.
They were originally designed for sealed 4x12's, so go sealed.
/sreten.cb951303 said:
Hi,
Wrong. Open backed cabinets cancel low bass and do not sound fat.
They work best with the higher Qts guitar drivers that are not suitable
for sealed boxes. I'm no expert on guitar speakers so if they where
originally designed for sealed 4x12's then go with that.
In my first post I should have said not particularly suited to sealed
in terms of PA / hifi speakers. In a sealed box ~ 1cuft they will
sound fat - as in around 200Hz boosted fat.
/sreten.I started making musical instrument speakers before hi-fi. You have a lot of leeway with a guitar speaker. Don't worry about it. Make it sealed between 1 and 2 cubic feet and it will be fine. Open will have more midrange and be looser. Sealed will be tight sounding for good dropped D chunk. I would just model the dimensions on practicality. Wide enough to hold your amp. 10 to 12 inches deep. 18" high or so. Done.
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