8" Transmission Line options

[Grumpy_Git]

Hi there everyone

Further to my attempts at diy-ing a HEIL I want to mate it to a TL. I've not got round to plotting the freq response/sensitivity of my heil but currently expect similar freqs to the big heil and low 90s efficiency.

I now want to investigate the driver options for a reasonably compact TL.

I intend to get the MJK spreadsheets (if I can't find an existing design, which I havent so far) once I've figured out using it, but wanted opinions here first.

I'd like an 8" driver for the TL in a 2-way and it needs to be cheap (under £40 per driver ideally) so was looking at Eminence Alpha/Beta 8's and various Beyma units, would any of these be suitable for compact TLs or should I look at other drivers, I thought I'd ask before I have to attempt modelling for every driver I find.

The design wouldnt have to reach super-low as I already have dedicated Subs but if it could reach to 2-2.5kHz that would be ideal.

Thanks

Nick.

[Grumpy_Git]

Hello again

Time for a second try, I've managed to get a pair of my Diy Heils working and they are happily pumping out music at 91dB/2.82v/m, I've got them padded and working in place of the tweeters in a pair of B&W DM601's at the moment but I want to finish a set of speakers off so:

Who can suggest a decent but very budget (think under £35, so Eminence Alpha 8/ Beyma 8BR40/Tangband W6-789E price range) 6.5-8" drive units that make nice noise, if you can recommend an alignment to go with them, BONUS!

The Heil seems ok down to 1k any lower and it drops like a stone so woofers will need to handle at least that if not up to 2kHz, as previously said about 90dB/2.82v/m.

If anyone has some questions to ask so that you can dial in some help please ask, I just cant afford to waste cash on big buck drivers right now and I've been out of the DIY game for about 8 years so trying to get some help on getting moving.

Thanks

Nick

[chris661]

Have a look around here

CPC | CPC - Over 100, 000 products from one of the worlds leading distributors of electronic and related products.

They stock many budget-end drivers from the likes of MCM.
Apart from that, Eminence are a decent brand.
How low do these need to go?

[Grumpy_Git]

Chris

I dont need to go particularly low as I've got a rythmik sub for the low stuff, 50-70Hz would be a nice compromise, and I dont need to reach 4k as the tweeter gets nice and low.

I dont know what the MCM/monacor/Beyma etc quality is like hence my request for model suggestions, it's a shame I cant afford any Vifa drivers let alone Volts or really as otherwise I'd just jump straight to a pair of BM220's.

I've built three Heils for a grand total of £75, so in keeping with that theme, its "how good can I get for the money". The Heils are VERY good and I dont think would be embarassed by the volts.

Nick.

[chris661]

I actually happen to have a pair of these lying around. The Qts might be a little low for transmission line use (I seem to remember they favour a Qts similar to sealed cabinets). They'd do reasonably well in a ported cabinet, though. PM me if you're interested - the front gasket is missing on one of them (siliconed the driver in place for a good seal, then struggled removing it), so I'm not looking for much money.

Apart from that, I think I'd try the Eminence Alpha 8, but the LF cut off may need to be raised a little - I'm not sure how low TLs go, but I'd doubt it'd go below driver Fs. In a different alignment, the Beta 8 gives a smoother midrange response, and lower Fs. The lower Qts would mean a ported cabinet, though.
Have you bought the spreadsheets?

Chris

[Grumpy_Git]

Not bought the spreadsheets yet as my car is in for a re-spray and someone has decided to buy stuff on my Creditcard wiithout my permission so am having to hold off for a few weeks till its all cleared.

I'll have a think/fiddle/play with some bits and pieces over the weekend and we will see where we end up.

Thanks Chris

Nick.

[Tliner]

HI All,

If you want true top-end DIY transmissionline 8" speakers which stand only 890mm high (35") check out Aspen's VSonics at Aspen Amplifiers. Go to products, VSonics for the info. Kits have been sold in the UK, USA and European countries with great accliam. Cheers,
TL.

[Grumpy_Git]

Tliner, I know the Aspen line quite well as I have followed them for a while now and own one of the amps.

As I've said though, I cant currently afford to spend massive amounts, also I want something to use with the tweeter I've made.

Nick.

[GM]

Originally Posted by Grumpy_Git

I'd like an 8" driver for the TL in a 2-way and it needs to be cheap (under £40 per driver ideally) so was looking at Eminence Alpha/Beta 8's and various Beyma units, would any of these be suitable for compact TLs or should I look at other drivers..........

Greets!

Fs/Qts defines a max flat impedance TL, its ~equivalent to a T/S max flat vented alignment, so one can use this to find the required Qts for a given Fs, etc. to get the desired F6. From this we see that the Eminence driver's Qts is a bit low and the only Beyma I'm familar with has too high an Fs.

FWIW, for your type of app, i.e. cheap, I normally used either Radio Shack or similar generic car audio or general purpose 'full-range' drivers like this LSL200W appears to be: Browse for Products | CPC

Since all of them IIRC were built before I began using T/S, net Vb was based on driver Sd, Fs and a simple reflex port = Sd, or ~3.6 ft^3 for this driver. They all performed quite good within the limits of the quality of the drivers, though of course measuring and using software to optimize them might yield a larger or smaller net Vb.

GM

[mondogenerator]

I cant really recommend much, as i havent had an 8" drivers for a long time. but i have some 10" basscab speakers.....not sure how high the go or smooth.. i might use a pair myself.

I doubt theyre really what youre looking for but pics anyway:





or try madisound....maybe these 5¾" aura sound are still $12 each.......fr looks good enough for the price.