HT240ZO Proj Ready to Start

[robert]

I bought 4 and have been working with them pretty intensely since I got back...

1.) Bass Reflex doesn't cut it; Fb is too high and they run out of excursion above and below it.

2.) Paul K. graciously designed a very cool "non-standard" ; ) enclosure for them that will work very well (down to 30Hz!) and partially corrects this problem, but it is quite large and can only accept a single driver. I am assuming the ML-TQWT backwave partially suspends the driver along with the port resonance, and hope I correctly figured how it works!

At present I am looking at 2 options: Paul K's ML-TQWT with a single driver, or a sealed design with a pair of drivers and F3 of 59Hz or so.

It doesn't seem "right" to use a 9.5" driver in an alignment that F3's at 59Hz, but it does have benefits in power handling at F3, an 8 ohm load, and a smaller cabinet. It also means a tower can hit 104dB anechoic and near 110dB in-room at 120 watts / 60Hz. I hate the idea of a big 3-way with a sub, but want to make these work.

With sealed option: when reverse-mounting a woofer to cancel even-order harmonics, how high can you cross over?

This is part of a tentative plan for the sealed 3-way tower. Given driver frame and magnet are "small" relative to wavelength at the tentative crossover frequency (250 - 350Hz), what do y'all think???

Cheers All / Robert

[Chris Roemer]

> I bought 4 and have been working with them
> pretty intensely since I got back...

> 1.) Bass Reflex doesn't cut it; Fb is too
> high and they run out of excursion above and
> below it.

> 2.) Paul K. graciously designed a very cool
> "non-standard" ; ) enclosure for
> them that will work very well (down to
> 30Hz!) and partially corrects this problem,
> but it is quite large and can only accept a
> single driver. I am assuming the ML-TQWT
> backwave partially suspends the driver along
> with the port resonance, and hope I
> correctly figured how it works!

> At present I am looking at 2 options: Paul
> K's ML-TQWT with a single driver, or a
> sealed design with a pair of drivers and F3
> of 59Hz or so.

> It doesn't seem "right" to use a
> 9.5" driver in an alignment that F3's
> at 59Hz, but it does have benefits in power
> handling at F3, an 8 ohm load, and a smaller
> cabinet. It also means a tower can hit 104dB
> anechoic and near 110dB in-room at 120 watts
> / 60Hz. I hate the idea of a big 3-way with
> a sub, but want to make these work.

> With sealed option: when reverse-mounting a
> woofer to cancel even-order harmonics, how
> high can you cross over?

> This is part of a tentative plan for the
> sealed 3-way tower. Given driver frame and
> magnet are "small" relative to
> wavelength at the tentative crossover
> frequency (250 - 350Hz), what do y'all
> think???

> Cheers All / Robert

34 Hz in 3.5 vented cf won't cut it?

[robert]

> 34 Hz in 3.5 vented cf won't cut it?

Oh no, the F3 is good, it's just that I built the box in SoundEasy and cranked the power up in the sim. The driver very rapidly runs out of excursion below Fb with a few watts and doesn't seem to like a lot of power above it either. It would demand a rumble filter and be limited to some degree.
On a sub, no problem, but on a "main" speaker, it's a bit of an issue.

Guaranteed from this day forward, I will box-sim before I buy : ) I still think they have some promise, but maybe not in the way I thought. And, there's still that ML-TQWT to try out...

R/Robert

[Pete Schumacher ®]

> Oh no, the F3 is good, it's just that I
> built the box in SoundEasy and cranked the
> power up in the sim. The driver very rapidly
> runs out of excursion below Fb with a few
> watts and doesn't seem to like a lot of
> power above it either. It would demand a
> rumble filter and be limited to some degree.
> On a sub, no problem, but on a
> "main" speaker, it's a bit of an
> issue.

> Guaranteed from this day forward, I will
> box-sim before I buy : ) I still think they
> have some promise, but maybe not in the way
> I thought. And, there's still that ML-TQWT
> to try out...

> R/Robert

You're going to run out of excursion with either the ML-TQWT or a vented box below tuning, as they both completely unload the woofer.

Instead of shooting for the lowest F3, how about a smaller than "optimum" enclosure tuned below what you'd normally tune? You get better F3 than a sealed box and better power handling than a larger vented box.

[robert]

> You're going to run out of excursion with
> either the ML-TQWT or a vented box below
> tuning, as they both completely unload the
> woofer.

> Instead of shooting for the lowest F3, how
> about a smaller than "optimum"
> enclosure tuned below what you'd normally
> tune? You get better F3 than a sealed box
> and better power handling than a larger
> vented box.

I'll give that a try; I think SE will sim a square wave near resonance and check for excessive ringing, too.

Robert