A little more Zing up Top ?

[LICORNE]

Todd is right on when adding tweeters the syatem is out of phase.

I remember EV Gladiator in 70's What a joke.

Quote by OLD GUY:
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Lots of systems running Altec use tweeters. I've seen dozens. The ONLY people doing what you say is CPC. One example does not set the rule
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Not quite check this out.



.............

[Todd W. White]

I remember when Altec put a huge system in a sports arena in Japan in the late 80's/early 90's - Osaka-Jo Hall as I recall it - they had a really NEAT cluster with Mantaray's/299's, 816's, and, yes, MR902-16HF SuperTweeters.

Phasing wasn't a real problem in that system for two reasons:

1. The entire cluster was properly designed and built around a tight acoustic center.

2. The only people who could HEAR the SuperTweeters were those who were sitting no more than 20 feet away, and, since all of the seating was WAY further, phasing between the devices wasn't an issue...

[Old Guy]

Originally posted by CONVERGENCE:
Not quite check this out.

[.............

<font size="2" face="Verdana, Helvetica, sans-serif">That makes no sense at all. If anything, that top horn is being used as a tweeter.

With today's digital control the systems are NOT out of phase. this is not the 1930's convergence.

The past is the past.

[GM]

Originally posted by tomt:

Parts Express:Constant Directivity Horn
Parts Express:Goldwood GT-1005 Wide Dispersion Piezo Tweeter

<font size="2" face="Verdana, Helvetica, sans-serif">FYI, all the reviews I've read of the Goldwood, etc., el cheapo piezos is that they are truly horrible, so not a contender IMO. Not familiar with the CD horn per se, but I have some very similar design/constructed phenolic diaphragm units from the early '70s sold through RS, Olson, etc., that are quite good, though they roll off above ~12 kHz, so while a pair are considerably cheaper than the piezo I conditionally recommended, it may still be the better choice overall.

As always though, YMMV.

[Old Guy]

The Goldwood piezos are sorta OK but not great according to a number I've talked to.

There are some miserable ones from China.

Motorola/CTS are available from Martin Pro Sound in Cleveland, and others.

[GM]

Originally posted by CONVERGENCE:

A mid high combo 3 way bi amp VOTT or any other theater type or Touring concert system don't use tweeters.

<font size="2" face="Verdana, Helvetica, sans-serif">This isn't true, but it's irrelevant to this thread since AFAIK Will's are used in a HIFI app.

WRT CPC stacking multi-cells, I imagine it's as much about creating a different polar response as it is about using one as a tweeter, but even if I'm wrong it's still a ridiculous solution to Will's situation IMO, especially considering he asked for an inexpensive one.

[GM]

Originally posted by Todd W. White:
Wente & Thuras spent months and months and months in a vain attempt to get the original 3-way WE theatre systems with the Bostwik (sp?) tweeters in phase - they finally gave up and threw the tweeters away.

<font size="2" face="Verdana, Helvetica, sans-serif">Yeah, it's not intuitive that the tweeter needed to be mounted ~15 ft behind the baffle due to the horn's folded path-length. Still, these guys were so brilliant, designing systems that to this day have hardly been improved upon in any fundamental way, so kind of surprised they didn't have a clue.

[joyspring]

Stuart:

DSP room correction is now de rigeur in most mixing and dubbing stages. You now see home AV receivers with Audyssey MultiEQ in many pro settings...

I use the Denon AVR-3806s at home and have req'd AVR-4306s for work -- they really are the dog's *****x for sub-optimal acoustics and are unbeatable for good rooms.

What's more, the AVR-3806 retails for US$1299, has seven high-quality 100W amplifiers built-in, a plethora of decoders... what a deal!

GM / Old Guy / Will:

Using piezoelectric drivers for that last octave is a great idea, one that I would never have thought to ever be entertained on this forum.

I've found that the Moto (now CTS) piezo drivers are a LOT more consistent than the Goldwood drivers...

I've also found that it's helpful to move the crossover point even higher than 8 kHz so the transition (particularly in power response) is even less noticeable; 10 kHz works well. Thankfully it's fairly simple to design a xover around the driver's shunt capacitance.

Convergence:

I'll agree with GM that the CPC MF/HF pack is an awfully wasteful and heavy means to achieve matching polar and power response at crossover and time alignment between MF and HF drivers.

GM:

Yeah, it's not intuitive that the tweeter needed to be mounted ~15 ft behind the baffle due to the horn's folded path-length. ...so kind of surprised they didn't have a clue.

<font size="2" face="Verdana, Helvetica, sans-serif">Oh, I'm certain they recognised that the physical displacement between drivers incurred a *bit* of a phase problem but they probably also recognised that building a passive cascaded all-pass network to compensate for 10+ mS with acceptable insertion loss and distortion would've been quite difficult with the componentry available at that time

BobR

[Langhaar]

i use jbl 2404 H on top of the mantaray mr94b crossed at 5 Khz with an active crosover slope 24db. Works very well.

[Old Guy]

If I could make a weak analogy, it's a lot like cooking.

Just as a lot of dishes use excessive spices to cover up meat starting to turn, many installers use DSP to make junk acceptable.

Those spices in smaller quantities can make fresh meat taste good too. I like spicy food.

Anyway, point is DSP is only as good as the person who implements it. Just like an installation without DSP.

Personally I think DSP is great. Not something to use for a major ilneess, but fine as pick me up for an otherwise good system.