Varying the dimensions on a Thiele 806 cabinet

[RJ Guitars]

Hello AGF,

Does anybody know what the final outcome would be if a person changed the dimensions on a Thiele 806 cabinet while keeping the internal volume the same?

The intention is to create a speaker cabinet that will match up to a Dumble head approx 20" wide. Could it possibly be as simple as just reducing the height or depth and maintaining the ideal 1.3cf volume?

rj

P.S. - Here is an interesting FWIW on the topic... http://cgi.ebay.com/THIELE%2FTHEILE--EV ... 5006r27817

[odourboy]

Hello AGF,

Does anybody know what the final outcome would be if a person changed the dimensions on a Thiele 806 cabinet while keeping the internal volume the same?

The intention is to create a speaker cabinet that will match up to a Dumble head approx 20" wide. Could it possibly be as simple as just reducing the height or depth and maintaining the ideal 1.3cf volume?

rj

P.S. - Here is an interesting FWIW on the topic... http://cgi.ebay.com/THIELE%2FTHEILE--EV ... 5006r27817

Well that worked for me. I did precisely that on a recent cab so a head cab would 'fit' on a TL808 cab set on it's side.

To the best of my knowledge, vented cab models using TS-parms do not consider cab dimensions, just internal volume. OTOH, port dimensions do matter, so you'll need to adjust the port if you change it's configuration when you resize the cab.

[dano-rator]

RJ,
Here's a quote re. resizing the thiele cab from the "My diy widebody thiele cab" thread here https://tubeamparchive.com/viewtopic.ph ... 6&start=30on AGF-

I don't think that you need to add a dummy wall, inside your fine cabinet. All you gotta do is adjust the (dept of the) reflex port to accomodate a larger cabinet.. I made a simulation in WinISD, comparing the 806 (36 liters netto) with the Mesa Boogie Thiele cab varity (40L netto), assuming that this cabinet volume is close to your design.

The port in the 806 is about 11 cm deep - and all you need to do (again assuming, that your cab is close to 40 L net) is trim the port dept down to appx 8 cm. This will trim the port to 60Hz like the 806, but with the advantage of a slight 3db boost around 60 Hz, which in effect will give you a bit more punch.

If you download the WinLSD beta, which can be downloaded for free, you can type in the data and see for yourself. Why carry emty space around, if you can use it to your benefit, instead. Hope you can use this input.

There are also alot of neat ideas there regarding this cabinet and variations thereof, worth a look if you've not seen it.

Dan

[Baxtercat]

I'd think the 1.3 ideal wouldn't be that important anyway, right? A little less might raise the pitch of the bass frequency a bit is all....sort of like changing a cap value. Nothing that would spoil the build.

I freehand adjusted down a homemade Thiele years ago [don't know the cubic feet I ended up with] and still had tons more bottom end than my other EV combos.
[I'd been competing onstage w/ the bass player's territory anyway.]

[RJ Guitars]

Thanks Guys, I'll do a bit more digging on the forum here, sounds like there have been efforts to do the same thing I'm asking about. I'll read up on them and see what has been learned previously.

rj

[marketleader]

As long as the volume remains the same you are basically good to go. There are some other considerations regarding ratios to avoid reinforcing resonances but it's probably not a major factor in a guitar cab. There are several online sources for designing ported cabinets if you know the specs of your speaker. A quick search found this one:

http://www.bcae1.com/spboxnew2.htm

Enjoy
Don

[bluesfendermanblues]

Hello AGF,

Does anybody know what the final outcome would be if a person changed the dimensions on a Thiele 806 cabinet while keeping the internal volume the same?

The intention is to create a speaker cabinet that will match up to a Dumble head approx 20" wide. Could it possibly be as simple as just reducing the height or depth and maintaining the ideal 1.3cf volume?

Yes, if the cabinet volume is the same, you can vary the cabinet dimensions to some degree. All you have to do is keep the volume of the port area (which is tuned to 60 Hz).

[RJ Guitars]

I know this cabinet was designed to be used with the big magnet EV speakers... I of course don't have one of those. I'd like to use something more common and affordable. The Boga Funk people make the claim that their Thiele 806 based cabinet works well with a variety of speakers...

As far as affordable and easy to get the Warehouse Guitar Speakers ET-65 is on my list. How well would that work?

rj

Product Specifications

* Power Rating 65 watts RMS
* 12” Paper cone
* Treated paper edge
* 1.75 inch voice coil
* Ceramic magnet
* Terminal Board
* Frequency Range 70-5000 Hz
* Sensitivity 1W/1M (SPL): 96 dB
* Nominal Impedance: 8 or 16 ohm
* Mesh dust cap
* Resonance frequency, Fs: 76 Hz

[marketleader]

You will need VAS and Q mesurements if you want to re-tune the box for a different driver. The manufacturer might already have them.

Here's a better site than the one I previously posted:

http://www.madisound.com/services/hifispeakerdesign.php

The other consideration is whether your new speaker is suitable for this type of enclosure.

If you can get the additional specs, and I'll run the numbers for you.

Don

[BobW]

RJ just go with the EV. It is twice the cost, but if you buy the warehouse speaker, then don't like it...you'll need to buy another anyway. Also a single 65W RMS is a little under rated for a 100W. the EV 12S or 12L can handle a 50/100W ODS , HRM, etc.

Boogafunk is actually one person here in Huntsville, AL who makes identical TL806 cabs. They are built very solid with a truckbed liner coating on the outside (or other options) for durability. Scottie is a great guy, but after looking at his cabs, I decided to build my own based on the EV plans. It's not that difficult to DIY, and the $ you save on the cab would pay for the EV. just sayin.

[Bob-I]

As far as affordable and easy to get the Warehouse Guitar Speakers ET-65 is on my list. How well would that work?

I for one love Warehouse speakers, I have 6 of them in various cabs and amps. For the record, I listened to the ET-65 at the ampshow recently, then bought a reconed EVM12L.

The Warehouse speakers i like best are the Veteran30 and the Brittish lead. I compared them directly to the ET-65 and overall I like these 2 best.

[marketleader]

RJ, I don't think I've ever heard G12-65 speakers in a ported cabinet and I was unable to find any thiele specs so my guess is that they might not be appropriate for that usage. If the manufacturer comes up with VAS and Q measurements though, let me know and I'll run it through box response software.

Enjoy,
Don

[Zippy]

Don,

Have you done (or are you aware of) a sensitivity study of this cabinet design? What I am hoping to learn is what parameters (speaker specifications) really matter. If we could learn the "error bar" on the parameters of interest, then we might better be able to select alternative speaker options that would require no changes to the configuration of the cabinet. Might that work here?