Back Loaded Horn with Passive Radiator?

[GM]

Originally posted by Antripodean

The tuning down to the 30s is being acheived with the MLTL long only?

The Z driver dimension with 2 drivers..........

Greets!

You're welcome!

Correct.

When drivers are vertically oriented on the baffle, 'zdriver' is the midpoint between the two so that the different loadings average out.

GM

[GM]

Originally posted by rjbond3rd

I interpreted GM's reference to 30's response to mean he put the CSS FR126S into the RS 40-1354. Let's see what the man himself says but I think Zdriver in a two-driver MLTL is usually the same for both drivers, i.e., the drivers are mounted on different panels at the same height, usually front and back, but I'm interested to hear whether there's a better position for the second driver.

Correct, but I assumed he was referring to the Alpair MLTL in the referenced thread that sims into the 30s.

If a bipolar layout is used, then 'zdriver' is the center-line for both.

GM

[rjbond3rd]

Originally posted by GM Here's a write-up I did many moons ago. Pic is them during voicing, so unfinished. On a whim, I brought them to a DIY Meet and was pleasantly surprised that they measured within +/- 3 dB from 40-12.5 kHz tuned just by ear...

Yowie, that is a mind-blowing amount of tweakage, GM.

[GM]

Wound up doing more to get more detail out of them, though of course you can't make a 'silk purse out of a sow's ear', but they were very close to the 125 when it was BW limited to match, so if I'd bothered to add a decent super tweeter, who knows?

GM

[Antripodean]

Hi GM

Thanks for everything so far. I have drawn everything up and I am now having the boards cut for the cabinets.
I am making the MLTLs and also the BRs. As it is my first build, I am intrigued about the differences/similarities between the two configurations. I am going to do the listening test in situ in the home theater set up and also wanting to do some testing to actually know the frequency response.
So, this is also a shout out to fellow DIYers in Melbourne who have the gear and opportunity to do the testing. Please email, thanks

[PJN]

You can use the jordan very sucessfuly in a BLH, probably the same for the AN10. I've tried it with MLTL, but I like the BLH much better, much better base and dynamics. I used Martin king's spreadsheets to design these several years ago.

PJN

[Antripodean]

Hi PJN
They look great!! And I am sure they sound great too
I don't have access to MJK's Mathcad but I did read his back loaded horn articles and what really struck home was "If done correctly, a hybrid transmission line / back loaded horn enclosure will not require
any baffle step correction circuit which is the real big advantage. Imagine 94 to 98 dB SPL, at a 1 m distance for 1 watt of input, over the frequency range 50 Hz to 15-20 kHz produced by a single driver enclosure that is slightly bigger then a commercial tower speaker system."
Like many people I want to have a BLH but I dont have the space (height or size of room) to handle a massive cabinet. I am sure there is a BLH (TL hybrid) that I will be building soon Just need a design to make it happen