Microperf screens in Ottawa, Ontario - AVS Forum
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post #1 of 11 Old 09-25-2001, 03:19 PM - Thread Starter
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I am getting really confused about whether to go with a microperf screen or not. I had all but decided to spring for a Stewart microperf screen until I read that many viewers observe moire effects when used with LCD and DLP projectors, and many other individuals find that the negative effect on the sound of speakers behind the screen is too great. I think that this is a situation where I need to see a microperf screen for myself. Is there anybody in the Ottawa area who is using a microperf screen and who would not mind if I drop by to check it out?
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post #2 of 11 Old 09-25-2001, 05:01 PM
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Scott,

What projector are you considering? Only a few projectors have moire problems with microperfs (mostly high-res LCD's).

The poster who commented on the effects of the screen on acoustical performance does not (I assume) have direct experience with a microperf screen because they all come with an equalizer that cancels out the effects of the microperfs as part of their THX certification. Check that thread again, I think some people have posted more information there.

Regards,

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post #3 of 11 Old 09-25-2001, 06:07 PM
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Kam,
I am told that most equalizers can only help for 1 narrow position(interaction with room acoustics)so lean to left or right and come unglued.To think people get worked up about a visual cone of 30-45 degrees.
I will be glad to hear if your info is otherwise.Most people can get around using perfs and get better pics at lots less cost.They just dont seem to know how to do it.Like 2 centers(1 over-1 under)left and right shadow boxed off.
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post #4 of 11 Old 09-26-2001, 07:48 AM - Thread Starter
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Kam,

Thanks for the response. At this time I am leaning towards one of two projectors, the Sanyo PLV-60HT or the Sim2 HT200DM. I probably will not get a Stewart THX certified screen since my understanding is that the only difference between the Stewart THX microperf screen and the Stewart standard microperf screen is the equalizer. Since I will be equilizing all speakers within my home theater it does not seem to make any sense to pay for the THX screen.

Ron, using 2 center speakers with one above and one below the screen will result in cancellation effects. This is an option that I am unwilling to pursue.
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post #5 of 11 Old 09-26-2001, 10:51 PM
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Scott,

You may get some moire problems with the PLV-60, it uses the same LCD chips as the 10HT which has been known to have a nasty interaction with microperfs in certain setups. I would recommend checking with a sample if you decide on the PLV-60. If you want the 200DM instead you should also seriously consider the Plus Piano at $3k USD, it uses the same chip and to my eyes looked very good (it also has a six-segment colour wheel). At that price you could get two and still save money! http://www.avsforum.com/ubb/biggrin.gif

I didn't know you could get Microperfs without the THX certification! After all the screen was developed in cooperation with THX.

Ron,

In this case the equalizer is performing a different function than in most cases. It is not trying to correct deficiencies in room response, it is only canceling the attenuation introduced by the microperf screen. I believe that your statement relates more to correcting the effects of standing waves using equalization. In this case, it is difficult to get correct equalization for more than one location because the peaks and troughs of the standing waves are naturally very localized. However the equalizer included with the screen only corrects for the high frequency roll off when the sound passes through the screen, there should be no change as one moves off-axis. Besides, the high frequencies handled by the EQ are not affected by room acoustics because their wavelengths are too small.

Not being an expert in acoutics, perhaps this question is better referred to Russ in the Special Guests forum.

Regards,

Kam Fung
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post #6 of 11 Old 09-27-2001, 08:21 AM - Thread Starter
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Kam,

The Plus Piano is an intriguing option, however, I am really interested in getting a projector that will be useable with a progressive-scan DVD player. I understand that Plus is coming out with another DLP projector that will accept a progressive-scan input and will be brighter. I will definitely consider this new projector if it is available within the next couple of months.
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post #7 of 11 Old 09-27-2001, 10:01 PM
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Kam,
The academy curve has to get factored in here somewhere.Presumably its in Stewart eq on THX approved screens for those who dont have it in THX rec/amps.

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post #8 of 11 Old 09-27-2001, 11:44 PM
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Ron,

No it is not, the EQ only corrects for the effects of the microperf screen. The idea is to get accurate reproduction no matter the source (music, DD, DTS, etc.). Re-EQ is the province of the receiver or pre-pro.

Regards,

Kam Fung
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post #9 of 11 Old 10-01-2001, 08:05 PM
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How do you use the equalizer that ships with the Stewart MicroPerf Screens??

Can it be used wiht a recaiver or only with a pre/pro ??

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post #10 of 11 Old 10-02-2001, 09:08 AM
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There seems to be some misleading info posted above.

The Stewart THX Micro-perf and the Stewart "regular" Micro-perf are two different screens.

In the case of the regular Micro-perf...it is simply any screen that Stewart sells that has very small perforations.

The THX screen is not like any screen material you have ever seen. For lack of a better description, the material is like a woven metallic cloth as opposed to a vinyl material with holes.

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post #11 of 11 Old 10-02-2001, 08:21 PM
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Cain,

I believe you need to have a pre/pro + amp type arrangement, the EQ need to go in the line level output of the centre channel. So unless you can get the decoded output of the centre channel (through pre-outs if you have them) and somehow feed it back in to your receiver for amplification you may be out of luck. You could try and see if you find the treble OK without EQ by draping a sample over your tweater.

Lee,

To the best of my knowledge the screen you describe is not a THX micro-perf. I don't think there is a distinction between micro-perf and THX micro-perf, micro-perf was developed in cooperation with THX. They are the same thing. I don't believe Stewart uses a woven material of any kind in their screen surfaces.

Regards,

Kam Fung
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