UE3 with new Keele-Horbach crossover

[bohdan]

Dear All,

Ultimate Equalizer V3 with new, Keele-Horbach crossover has been released. The crossover is described in AES paper:

Application of Linear-Phase Digital Crossover Filters to Pair-Wise Symmetric Multi-Way Loudspeakers Part 2: Control of Beamwidth and Polar Shape.
ULRICH HORBACH, AND D. B. (DON) KEELE, JR

Available from:

http://www.linkwitzlab.com/Horbach-K...t%202%20V4.pdf

For more information on features in this UE3 release, please read:

http://tech.groups.yahoo.com/group/S.../message/10808


Best Regards,
Bohdan

[Deward Hastings]

Read the first link and weep, all you guys who think MTM with spacing of more than half a wavelength (M to M) can be made to work (the way you think it does) with an ordinary crossover . . .

[daryl]

Read the first link and weep, all you guys who think MTM with spacing of more than half a wavelength (M to M) can be made to work (the way you think it does) with an ordinary crossover . . .

Two wavelengths M-M for an MTM Deward.

I think we are talking about how Deward thinks an MTM works.

That is I think you are thinking of it the way Joe D. did back in the day when he first introduced it.

Originally Joe thought he would achieve a flat power response and symmetrical lobing with a coincident driver array and Butterworth crossovers.

The ubiqitous application was the Swan IV speaker system with two Peerles 12" woofers per side in separate cabinets and MTM's with Focal midbasses and Dynaudio tweeters.

The Swan IV's crossover frequencies were 200hz and 2000hz (first order) and the midbasses were about 1.25 wavelengths apart at the crossover frequency.

The original D'Appolito concept didn't quite work as advertised because of the separation between the midbasses causing the power response to sag below the crossover frequency.

A 2.5 way (MMT) way is better to suited to the task.

The MTM is better used in the opposite way and that's how Joe uses them nowadays.

Rather than trying to achieve flat power response with MTM's you can use them instead to minimise reflected energy.

This approach is going to yeild an altogether different result.

More clarity/intelligability less diffuse sounding (more of you're recording less of you're room), great for THX certification.

The separation between the midbasses yeilds an reduction in off-axis energy just above the bass range.

The more the midbasses are separated the lower the frequency where the reduction in off-axis energy begins but you are bounded by how narrow of an beamwidth you are willing to accept before the tweeter comes into play and the secondary lobes which are working their way forward as frequency increases.

Using LR crossovers rather than Mrs. Butterworth provides further reduction of off-axis energy through the crossover region.

If you then use a tweeter with a wave-guide you can extend the reduction in off-axis energy even higher.

[Deward Hastings]

I think we are talking about how Deward thinks an MTM works.

I think Daryl didn't bother to read the linked article, doesn't have a clue how or what Deward thinks, and is equally clueless about how an MTM works (or doesn't).

The rest of your post, Daryl, doesn't even rise to silly. Been drinking tonight?

[daryl]

I think Daryl didn't bother to read the linked article, doesn't have a clue how or what Deward thinks, and is equally clueless about how an MTM works (or doesn't).

The rest of your post, Daryl, doesn't even rise to silly. Been drinking tonight?

Deward!

LOL

Do you expect a three driver MTM to be able to control it's radiation pattern as effectively as a nine driver array with a five way digital crossover?

MTM's can achieve considerable reduction in reflected energy through the critical midrange band with high output and symmetrical lobing.

They don't achieve flat power response or constant directivity just reduced reflected energy and they do it in a simple practical package.

You're assertion that MTM's don't work unless the midbasses are spaced less than a half wavelength is as clueless as it is illrelavent to the thread topic.

[bohdan]

Hi,

There is an AES article version of the same material as well with more explanations.

http://www.xlrtechs.com/dbkeele.com/...20Part%202.pdf

Best Regards,
Bohdan

[OlderMongrel]

Hi,

There is an AES article version of the same material as well with more explanations.

http://www.xlrtechs.com/dbkeele.com/...20Part%202.pdf

Best Regards,
Bohdan

Link not working for me.

John

[bohdan]

Hi John,

The link seems to be working OK for me. However, you can try

http://www.xlrtechs.com/dbkeele.com/papers.htm

There are lots of Keele's papers there and Keele-Horbach crossover is there too, and both: Part 1 and Part 2 are available.

Best Regards,
Bohdan

[greywarden]

See, now THIS is a reason fore me to go Active - one day - when I can afford so many drivers and amplifiers.

[Deward Hastings]

when I can afford so many drivers and amplifiers.

It is worth noting that the introductory discussion of paired driver spacing does make clear how to get some benefit from two mid drivers and a simple crossover . . . without the downside of wandering lobes and nulls and terrible power response that comes with the typical spaced-too-far-apart MTM layout. It's not a completely stupid layout . . . stupid is just the way it's usually done. The article explains how to make it work when they do have to be (what would otherwise be) too far apart, and yes, it's complex. It's a lot easier to keep the spacing at a half wavelength (or less) or, generally better still if you're going to use three drivers anyway, to make a WMT.