another transmission line question

[CharlieM]

The math and puter programs are over my head...
I'm wanting to marry a TL line with 10" woofer to my ESL panel crossing over at 500Hz with 24db slope. I'm looking at an Aurum Cantus AC-250F1 for this purpose.
Most ESL folks use an 8" for this but I need more puch-- thus, the 10" preference.

Since the ESL will sit atop the box, I will need the smallest box volume possible.

Please anyone jump in here and advise me on the woofer choice (or alternates) and on how small the box can be (willing to compromise some on bass extension to achieve minimum box size)

thanks all

[GM]

Define 'small'.

Anyway, assuming a SS amp and sufficiently large gage wiring, using a 0.29 Qts driver in a TL pretty much defines a compromised bass output and the only way to get any 'punch' out of it in a small TL would be to use a ~max flat impedance alignment which further reduces its bass extension, though this driver's high Vas will still keep it from being small by most folk's standards:

L = 45.125"
CSA = 146.4"^2

All dims i.d. and 1.5 lb/ft^3 polyfil stuffing density simmed.

GM

[CharlieM]

GM,
Thanks for the info. Let me better define "small" and invite you to advise me further. ESL's are big anyway and I'm trying to keep the TL box small to meet my design goal of 6ft total height. For the TL, I'm thinking a 7 1/2 ft tapered/folded line using a smaller than usual cross section to reduce the box size... that is; a line section about equal to the woofer's driven area at the front of the line, tapering to about 70% of that at the terminus. I will be driving the woofers and ESL panels separately with dual Carver 225W/channel amps so power shouldn't be a problem. I've attached a first draft drawing of the hybrid ESL/TL I have in mind. Please have a look and tell me what you think.

thanks!

Charlie

[GM]

Greets!

You're welcome!

Unfortunately, the thumbnail doesn't blow up enough to be legible. Anyway, here's the AC-250F1 in your TL:

GM

[GM]

Looks like you're better off just putting it in the same size sealed cab:

[CharlieM]

Yes, it certainly looks like sealed box of same volume would work better but please help me understand why... is the driver not suitable for a TL or is it my box configuration?
What could be changed to make it better?

I've attached a somewhat better scan (the file size restriction here is a killer)

thanks!

Charlie

[sreten]

Hi,

The simple fact is TL's are not volume efficient, so small / undersized
ones simply do not work well. Vented boxes AFAIK are smaller than
optimum TL's and sealed box is ~ half the vented volume again.

It seems you have 2cuft to 2.5cuft to play with, sealed is probably
best.
FWIW unless you have some independent test results you generally
cannot always trust chinese driver specifications, you should have
some way of verifying good distortion performance for example,
especially crossing over highish to an electrostatic.

/sreten.

[CharlieM]

What would be a good TL box configuration for the Aurum Cantus 10" driver? That is; with respect to the line cross-sections and the front and at the terminus and the line length? If this driver isn't good for the application, can you suggest one?
thanks,
Charlie

[GM]

Originally posted by CharlieM
Yes, it certainly looks like sealed box of same volume would work better but please help me understand why... is the driver not suitable for a TL or is it my box configuration?
What could be changed to make it better?

I've attached a somewhat better scan (the file size restriction here is a killer)

thanks!

Charlie

You're welcome!

It's just barely readable. FWIW I've had good luck with SnagIt 5.0 auto reducing big files to gifs I can post here.

It's the driver's specs, a ~2.4198 ft^3 net TL constitutes an acoustically large sealed cab, so it doesn't need a well damped pipe loading to get a ~I.B. response in a compact design, so the only advantage to loading it with a TL would be to damp the driver's impedance peak for an easy load to a high output impedance amp.

For low Q drivers, a high aspect ratio TQWT is preferred, ergo will be shorter for a given Fp:

L = 50"
SO = 149"^2
SL = 28"^2

All dims i.d. and 0.75 lbs/ft^3 polyfil stuffing density simmed.

GM