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post #66601 of 70896
Quote:
Originally Posted by dropzone7 View Post

... I do plan to use an acsoutically transparent screen and that is one of the last things I need to buy now. Not cheap. I'm not sure at the moment how high the tweeters are but it was all a compromise between seating height and where I thought the screen needed to sit. I have yet to run Audyssey so I should probably reserve my questions for when everything is setup and ready to go. I usually find that I'm standing up near the back of the room while evaluating sound and picture which is probably a bad idea as I would never stand to watch an actual movie in the room.

We're using an acoustically transparent screen by Seymour, and Audyssey MultiEQXT corrects very well for the transmission loss (only a couple of dB at the top of the frequency range, and truly transparent below). That's from the MLP -- I haven't measured it far off axis. The dialog is crisp and clear. Seymour is very good about answering questions, such as how far away you have to sit to not see the fabric pattern. We are about 12.5 feet away from a 130" wide (width, not diagonal) screen, and the fabric pattern is completely invisible.

By all means wait until your room is completely set up, and you have run Audyssey, before evaluating.
post #66602 of 70896
Quote:
Originally Posted by kbarnes701 View Post

Well there isn't really much point in trying to evaluate a half-finished room, with no seats, from a standing position at the back of the room, without Audyssey, and then saying that dialogue intelligibility isn’t very good. Sheesh.
I'm sure you are right...no point at this point.
post #66603 of 70896
Quote:
Originally Posted by garygarrison View Post

We're using an acoustically transparent screen by Seymour, and Audyssey MultiEQXT corrects very well for the transmission loss (only a couple of dB at the top of the frequency range, and truly transparent below). That's from the MLP -- I haven't measured it far off axis. The dialog is crisp and clear. Seymour is very good about answering questions, such as how far away you have to sit to not see the fabric pattern. We are about 12.5 feet away from a 130" wide (width, not diagonal) screen, and the fabric pattern is completely invisible.

By all means wait until your room is completely set up, and you have run Audyssey, before evaluating.

I too use the Seymour Centre Stage AT screen, after XT32 and my tweeters at ear height the dialog is superb! There is no lift in db I have to make to the centre channel after EQ, its perfect the way XT32 finds it.
post #66604 of 70896
Quote:
Originally Posted by garygarrison View Post

We're using an acoustically transparent screen by Seymour, and Audyssey MultiEQXT corrects very well for the transmission loss (only a couple of dB at the top of the frequency range, and truly transparent below). That's from the MLP -- I haven't measured it far off axis. The dialog is crisp and clear. Seymour is very good about answering questions, such as how far away you have to sit to not see the fabric pattern. We are about 12.5 feet away from a 130" wide (width, not diagonal) screen, and the fabric pattern is completely invisible.

By all means wait until your room is completely set up, and you have run Audyssey, before evaluating.

Yeah I have spoken to Chris several times. Very helpful guy and I plan to buy a Seymour screen.
post #66605 of 70896
Quote:
Originally Posted by RapalloAV View Post

I looked at your picture and the very first thing I thought looked wrong was the height of the tweeter looks too high.

I had a similar situation to you when I built my HT, in wall THX speakers that were placed before my three rows of seating over risers and the AT screen. I will never build a cinema with in wall front speakers again, it was a nightmare to fix my dialog issues and make changes after. My three front tweeters were too high, they should be inline with your ears when seated. In the end I removed my motorised masking, the screen and turned the speakers upside down so the tweeters were at the bottom, Klipsch confirmed this was fine to do. My dialog completely changed. Before this Audyssey XT32 was probably having a had time to make things right!

If you haven't lined the walls yet, I would set up a seat and measure exactly where your ears are in relation to the tweeter, then adjust the height of the speakers so the tweeter are level with your ears.

The way mine was....



I'm not sure how to get around the problem of tweeters too high for one row and too high for another. I measured the front seated ear height at 41" and rear at about 52". The tweeters are at 50 1/2". Moving the speakers down 10" looks really low. Should I just split the difference?
post #66606 of 70896
Quote:
Originally Posted by dropzone7 View Post

I'm not sure how to get around the problem of tweeters too high for one row and too high for another. I measured the front seated ear height at 41" and rear at about 52". The tweeters are at 50 1/2". Moving the speakers down 10" looks really low. Should I just split the difference?

Yes or go for the row that's most important.

I have three rows over risers so mine is even more difficult to line up than yours. I centred my tweeters to the most important row, the middle one.

All pretty easy really, that's why you need to address yours while its easy, even though you may think they look low don't stress......

Split the difference say and place them at 46" high. wink.gif
Edited by RapalloAV - 11/4/13 at 8:15pm
post #66607 of 70896
Quote:
Originally Posted by AustinJerry View Post

You have received a couple of explanations.  However, I will be doing some REW measurements tomorrow and I'll also take some measurements using your method.  I'll post the results and we can compare to see what the differences might be.  Sound like a plan?

AustinJerry,

That would be awesome! I believe you guys when you say that REW will be different that my meter measurements - I might have missed the explanation as to "why" though. Just curious for my own knowledge wink.gif
post #66608 of 70896
Quote:
Originally Posted by garygarrison View Post

I would think the continuous bottom to top sweep provided by REW would be much more informative than testing at intervals.

The Radio Shack meters do not have flat response. I have two of them -- both analog -- one new one and one from back when they published a response curve. The curve was so horrific looking that I can see why they would be reluctant to publish it. In my case, the room curve I got with REW looks much smoother than with either R.S. meter.

Interesting - I thought that the analogic RS meters were actually decent from a response perspective? FWIW, when I use the same meter (combined with published correction values) to measure my subwoofer response the plot is very flat. /shrug
post #66609 of 70896
Quote:
Originally Posted by mjodotcom View Post


Interesting - I thought that the analogic RS meters were actually decent from a response perspective? FWIW, when I use the same meter (combined with published correction values) to measure my subwoofer response the plot is very flat. /shrug

 

A naked meter is not flat.  When the RS SPL meter is used with REW, there is a calibration file that compensates for the meter's response characteristics.

 

I am attaching a copy of the calibration file.  Open it in a text editor like Notepad and you can see the correction values from 10Hz-1000Hz (the RS SPL is not good for measurements above 1000Hz).  If you import the data into Excel, you can chart it:

 

 

So, unless you compensate for the non-linearity of the meter, your measurements will not be accurate.  If you want to get fancy, import the offsets into your measurement worksheet and apply them to the existing measurements.  That would make your measurements more realistic.

 

RadioShack-33-2050-CS.zip 0k .zip file

post #66610 of 70896
Quote:
Originally Posted by AustinJerry View Post

A naked meter is not flat.  When the RS SPL meter is used with REW, there is a calibration file that compensates for the meter's response characteristics.

I am attaching a copy of the calibration file.  Open it in a text editor like Notepad and you can see the correction values from 10Hz-1000Hz (the RS SPL is not good for measurements above 1000Hz).  If you import the data into Excel, you can chart it:




So, unless you compensate for the non-linearity of the meter, your measurements will not be accurate.  If you want to get fancy, import the offsets into your measurement worksheet and apply them to the existing measurements.  That would make your measurements more realistic.

RadioShack-33-2050-CS.zip 0k .zip file

AJ,

Understood - that's what I ment by "combined with published correction values" in my last post. All I was saying is when I record measurements using those corrections with XT32 on everything looks nice and flat for my sub - which is good because that's what I hope to accomplish! From 200-2000hz is where that behavior is no longer observed per my other plots, but it sounds like that might be expected (just not quite sure why yet lol). Also, good to know RS meters aren't very good beyond 1khz! Guess a new USB mic is in my future to start playing with REW smile.gif
post #66611 of 70896
Quote:
Originally Posted by mjodotcom View Post

AJ,

Understood - that's what I ment by "combined with published correction values" in my last post. All I was saying is when I record measurements using those corrections with XT32 on everything looks nice and flat for my sub - which is good because that's what I hope to accomplish! From 200-2000hz is where that behavior is no longer observed per my other plots, but it sounds like that might be expected (just not quite sure why yet lol). Also, good to know RS meters aren't very good beyond 1khz! Guess a new USB mic is in my future to start playing with REW smile.gif

Not only is the RS meter not very good above 1K, but the published correction values above 1K vary to the degree that at the very frequency some compensation charts recommend adding a dB or two, other charts recommend subtracting. I had a few such charts at one time; as I remember, the variation was the greatest above about 5 to 8K, and completely out of hand above 10K. A possible reason for the discrepancy between correction charts in the high treble is that there may be great variation between RS meters of the same model, so if one audiophile laboriously compared one of them to a calibrated mic to create a comp chart, the corrections may work just fine for the meter he/she happens to have, but be very wrong for the RS meter someone else has.
post #66612 of 70896
Quote:
Originally Posted by garygarrison View Post
 
By all means wait until your room is completely set up, and you have run Audyssey, before evaluating.

 

+1.

 

I made an apple pie once and it tasted really bad before I baked it.

post #66613 of 70896
Quote:
Originally Posted by dropzone7 View Post

I'm not sure how to get around the problem of tweeters too high for one row and too high for another. I measured the front seated ear height at 41" and rear at about 52". The tweeters are at 50 1/2". Moving the speakers down 10" looks really low. Should I just split the difference?

 

I would target the row that is most likely to be used most often. At least that way you get one row right. Splitting the difference is a good way to ensure that neither rows is right. Or, choose speakers that have the off-axis directivity characteristics that meet your requirements in the first place. As the speakers are already bought, you will inevitably have to compromise one way or another - this is normal for HT builds, even professional cinemas don't promise that every seat is a really great seat.

post #66614 of 70896
Quote:
Originally Posted by kbarnes701 View Post

I would target the row that is most likely to be used most often. At least that way you get one row right. Splitting the difference is a good way to ensure that neither rows is right. Or, choose speakers that have the off-axis directivity characteristics that meet your requirements in the first place. As the speakers are already bought, you will inevitably have to compromise one way or another - this is normal for HT builds, even professional cinemas don't promise that every seat is a really great seat.

Yes, not to mention the other part of the problem which is screen placement that will be a compromise between seating heights of two different rows. I would guess that the back row will be the most often used as I will rarely have eight people here to watch a movie. Typically it will be four or just the wife and myself. If I were to optimize things for a single row of seats it would be the back so I guess I should just concentrate on that now. If that's the case then the speakers really only need to come down an inch or two.
post #66615 of 70896
Quote:
Originally Posted by dropzone7 View Post
 
Quote:
Originally Posted by kbarnes701 View Post

I would target the row that is most likely to be used most often. At least that way you get one row right. Splitting the difference is a good way to ensure that neither rows is right. Or, choose speakers that have the off-axis directivity characteristics that meet your requirements in the first place. As the speakers are already bought, you will inevitably have to compromise one way or another - this is normal for HT builds, even professional cinemas don't promise that every seat is a really great seat.

Yes, not to mention the other part of the problem which is screen placement that will be a compromise between seating heights of two different rows. I would guess that the back row will be the most often used as I will rarely have eight people here to watch a movie. Typically it will be four or just the wife and myself. If I were to optimize things for a single row of seats it would be the back so I guess I should just concentrate on that now. If that's the case then the speakers really only need to come down an inch or two.

 

That, to me, seems to be the best solution. Optimising audio for multiple seat rows is always problematic and the cause of much discussion. I would also try to angle the speakers towards the 'money seats' too if possible, assuming they might still be off-axis to some extent, although that might make things worse for the front row.

post #66616 of 70896
Quote:
Originally Posted by kbarnes701 View Post

That, to me, seems to be the best solution. Optimising audio for multiple seat rows is always problematic and the cause of much discussion. I would also try to angle the speakers towards the 'money seats' too if possible, assuming they might still be off-axis to some extent, although that might make things worse for the front row.


I'm not sure I can tow in these speakers since they are inwall types. I guess I could use some sort of shim on one side of the mounting opening to create a small angle towards the good seats.


Design

Infinite Baffle, Back-Boxed, "D'Appolito" In-Wall LCR

Frequency Response

62Hz-20kHz+3dB

Sensitivity

90dB

Nominal Impedance

4 Ohms

Crossover Frequency

2kHz

Recommended Amplifier Power

50-250 Watts

Maximum Output (per pair)

110dB

Placement

2" x 4" Stud Wall or Ceiling

Drive Units

Tweeter:

Woofer:

Input Connection

Spring Loaded, Push Post, Accepts 12 Gauge Wire

Dimensions


Mounting System

"dog-Leg" clamps


1-inch SEAS Silk Dome

Two 6.5-inch Poly, 5mm Excursion

30.5-inches

10.5-inches

3.75-inches

29.38-inches

9.38-inches
post #66617 of 70896
I trust you're aware that their 4 Ohm impedance limits the choices of receiver you can use with them if you want to be able to reach full volume levels.
post #66618 of 70896
Quote:
Originally Posted by Selden Ball View Post

I trust you're aware that their 4 Ohm impedance limits the choices of receiver you can use with them if you want to be able to reach full volume levels.

Yes, I'm using an Emotiva XPA-5 amp to power the front speakers and one set of the surrounds which are also 4 ohm speakers. I should be getting 300W per channel into 4 ohms. The speakers sounds really good. I bought them used and they are several years old. An inwall speaker would not be my first choice but I am limited by the depth of the room and did not have several feet to spare that would be needed to place large floorstanding speakers behind a false wall. I'm happy with the speakers, just looking for a little better voice clarity. I understand that all of this is pointless until the room is setup and ready to go. I know I'm putting the cart before the horse here but you guys have given me a lot to think about now and I think I will drop the speakers down a few inches. I probably need to build the riser and get the seating in place so I have some sort of reference for everything else.
post #66619 of 70896
Quote:
Originally Posted by dropzone7 View Post
 
Quote:
Originally Posted by kbarnes701 View Post

That, to me, seems to be the best solution. Optimising audio for multiple seat rows is always problematic and the cause of much discussion. I would also try to angle the speakers towards the 'money seats' too if possible, assuming they might still be off-axis to some extent, although that might make things worse for the front row.


I'm not sure I can tow in these speakers since they are inwall types. I guess I could use some sort of shim on one side of the mounting opening to create a small angle towards the good seats.

 

 

In-wall speakers often have adjustable tweeters that can be angled towards the listener. I take it that these don't. I'm sure with a bit of ingenuity they could be mounted in such a way that they are angled slightly towards the MLP.

post #66620 of 70896
Quote:
Originally Posted by dropzone7 View Post
 
Quote:
Originally Posted by Selden Ball View Post

I trust you're aware that their 4 Ohm impedance limits the choices of receiver you can use with them if you want to be able to reach full volume levels.

Yes, I'm using an Emotiva XPA-5 amp to power the front speakers and one set of the surrounds which are also 4 ohm speakers. I should be getting 300W per channel into 4 ohms. The speakers sounds really good. I bought them used and they are several years old. An inwall speaker would not be my first choice but I am limited by the depth of the room and did not have several feet to spare that would be needed to place large floorstanding speakers behind a false wall. I'm happy with the speakers, just looking for a little better voice clarity. I understand that all of this is pointless until the room is setup and ready to go. I know I'm putting the cart before the horse here but you guys have given me a lot to think about now and I think I will drop the speakers down a few inches. I probably need to build the riser and get the seating in place so I have some sort of reference for everything else.

 

It really is impossible to assess dialogue clarity until the room is in a far more finished state. All we can do is to give pointers about the potential causes of dialogue unintelligibility (which I did in an earlier post) so you can take this into account during the room design. You need to avoid unwanted reflections basically, which means some form of acoustic treatments, placed properly. This isn’t the thread to go into detail on that though. Audyssey will be of no help to you at all until the room is finished and you can calibrate it as it is at that time. 

post #66621 of 70896
Quote:
Originally Posted by AustinJerry View Post
 

 

You have received a couple of explanations.  However, I will be doing some REW measurements tomorrow and I'll also take some measurements using your method.  I'll post the results and we can compare to see what the differences might be.  Sound like a plan?

 

@Mjodotcom:

 

I am installing some room treatments today and running into some issues.  It doesn't look like I will have the time to conduct the experiment I promised.  Since my original note, there have been some additional comments.  Is the experiment still necessary?

post #66622 of 70896
Quote:
Originally Posted by dropzone7 View Post

Quote:
Originally Posted by kbarnes701 View Post

That, to me, seems to be the best solution. Optimising audio for multiple seat rows is always problematic and the cause of much discussion. I would also try to angle the speakers towards the 'money seats' too if possible, assuming they might still be off-axis to some extent, although that might make things worse for the front row.


I'm not sure I can tow in these speakers since they are inwall types. I guess I could use some sort of shim on one side of the mounting opening to create a small angle towards the good seats.


Design

Infinite Baffle, Back-Boxed, "D'Appolito" In-Wall LCR

Frequency Response

62Hz-20kHz+3dB

Sensitivity

90dB

Nominal Impedance

4 Ohms

Crossover Frequency

2kHz

Recommended Amplifier Power

50-250 Watts

Maximum Output (per pair)

110dB

Placement

2" x 4" Stud Wall or Ceiling

Drive Units

Tweeter:

Woofer:

Input Connection

Spring Loaded, Push Post, Accepts 12 Gauge Wire

Dimensions


Mounting System

"dog-Leg" clamps


1-inch SEAS Silk Dome

Two 6.5-inch Poly, 5mm Excursion

30.5-inches

10.5-inches

3.75-inches

29.38-inches

9.38-inches

I hope you don't like listening loud as those speakers apparently aren't capable of it, going by these specs.

Maximum output of 110db per pair. THX Reference requires EACH speaker be capable of 105db peaks at the listening position. If the speakers are rated at 110db per pair, that would mean 104-107db per speaker. At a listening distance of 4m/13.2 feet, the per speaker maximum would be 92-95db. Chances are, they could begin distorting even before that.

Also, vertical d'appolito arrays aren't ideal for multi tiered seating. By their very design, a vertical d'appolito array produces pretty good horizontal response. Unfortunately, vertical changes in listener height cause phase issues subject to the angles relative to the speaker face.

This is the same reason a horizontal D'appolito array makes a poor center channel design. The phase issues from the design mean cancellation and peaks at varying frequencies for anyone NOT seated dead center of the speaker.


Max
post #66623 of 70896
Quote:
Originally Posted by djbluemax1 View Post

I hope you don't like listening loud as those speakers apparently aren't capable of it, going by these specs.

Maximum output of 110db per pair. THX Reference requires EACH speaker be capable of 105db peaks at the listening position. If the speakers are rated at 110db per pair, that would mean 104-107db per speaker. At a listening distance of 4m/13.2 feet, the per speaker maximum would be 92-95db. Chances are, they could begin distorting even before that.

Also, vertical d'appolito arrays aren't ideal for multi tiered seating. By their very design, a vertical d'appolito array produces pretty good horizontal response. Unfortunately, vertical changes in listener height cause phase issues subject to the angles relative to the speaker face.

This is the same reason a horizontal D'appolito array makes a poor center channel design. The phase issues from the design mean cancellation and peaks at varying frequencies for anyone NOT seated dead center of the speaker.


Max

I don't know how I could stand to have it any louder. Just setting each speaker to 75db in my room makes it more than loud enough for me. I have yet to hear any distortion and I have had them turned up past my reference volume but not for very long. Again, I would not have chosen inwall speakers had the space been available to create a false wall with large floor standing speakers behind it. I'm not sure why I picked these speakers other than that I thought I got a good deal on them and I had read good things about Snell. Now, if I had the space I would be using the JBL 3677 cinema speakers which are fairly shallow in depth but not enough to preserve what precious little space I have. Now you have me curious to see how loud I can play these inwall speakers.
post #66624 of 70896

I have a wonderful 5-speaker set of Snell Acoustic .5's (from the late '90's).  I have the E towers, the K surrounds, and the matching center channel.  They found a new home in my bedroom several years ago, but Snell has always been a favorite.

 

My understanding is that Snell ceased to exist as a separate company a number of years back, having been bought out by Boston Acoustics.  Did you purchase your speakers used, or has the Snell brand been resurrected?

post #66625 of 70896
Quote:
Originally Posted by dropzone7 View Post

I don't know how I could stand to have it any louder. Just setting each speaker to 75db in my room makes it more than loud enough for me. I have yet to hear any distortion and I have had them turned up past my reference volume but not for very long. Again, I would not have chosen inwall speakers had the space been available to create a false wall with large floor standing speakers behind it. I'm not sure why I picked these speakers other than that I thought I got a good deal on them and I had read good things about Snell. Now, if I had the space I would be using the JBL 3677 cinema speakers which are fairly shallow in depth but not enough to preserve what precious little space I have. Now you have me curious to see how loud I can play these inwall speakers.

I was in exactly the same boat as you, no room to place towers, I used the Klipsch THX KL-7800 inwall for my three fronts. I also use Klipsch THX in ceiling for all my surrounds and highs.
post #66626 of 70896
Quote:
Originally Posted by AustinJerry View Post

I have a wonderful 5-speaker set of Snell Acoustic .5's (from the late '90's).  I have the E towers, the K surrounds, and the matching center channel.  They found a new home in my bedroom several years ago, but Snell has always been a favorite.

My understanding is that Snell ceased to exist as a separate company a number of years back, having been bought out by Boston Acoustics.  Did you purchase your speakers used, or has the Snell brand been resurrected?
I bought these on EBay a few years ago and they just sat here until recently. They are used but in good shape. I was surprised at how heavy they are and they sound really good to me.
post #66627 of 70896
Quote:
Originally Posted by RapalloAV View Post

I was in exactly the same boat as you, no room to place towers, I used the Klipsch THX KL-7800 inwall for my three fronts. I also use Klipsch THX in ceiling for all my surrounds and highs.
I remember looking at those and they are quite pricey if I recall. I was also looking for something as tall as possible but still affordable. I was thinking they would look neat behind the screen. Are the horns in your in walls similar to Klipsch floorstanding speakers?
post #66628 of 70896
Quote:
Originally Posted by dropzone7 View Post

I remember looking at those and they are quite pricey if I recall. I was also looking for something as tall as possible but still affordable. I was thinking they would look neat behind the screen. Are the horns in your in walls similar to Klipsch floorstanding speakers?

Correct, they are pricy!
Why were you looking for something as tall as possible, I don't understand, the screen covers them?
The inwall Klipsch THX are the same specs as the Klipsch THX in a box.
They all use the same similar horn design.
post #66629 of 70896
Got a quick few questions related to mic positioning (from the FAQ). I have a very high backed leather chair such that my ears actually below the top of the backrest. I know the recommendation for this scenario is to keep the mic 12-15'' away from the back of the couch, but I have a few additional questions:

-The FAQ says to make sure the mic is high enough to "see" the back speakers. Does that just mean that if looking at the rear speaker from the mic I can make out the whole rear surround, or should the speaker view from the mic's perspective clear the back by a few inches? Also, does pushing the mic up this high negate the need to keep it 12" from the couch back?

-For positions 2 and 3, it says to never place the mic outside of the angle spanned between the front L/R speakers. Does this mean that I need to make sure the toe-in (manufacturer recommends a small amount) is shallow enough such that positions 2 and 3 are either on axis or inside where the speaker is pointed?

-As far as recommended positions 7 and 8 are concerned, does the bottom of the mic need to be a certain distance up from the couch top? Also, are there any concerns if I have the mic further back along the backrest since it is quite wide?
Edited by mjodotcom - 11/6/13 at 4:45am
post #66630 of 70896
Quote:
Originally Posted by AustinJerry View Post

@Mjodotcom:

I am installing some room treatments today and running into some issues.  It doesn't look like I will have the time to conduct the experiment I promised.  Since my original note, there have been some additional comments.  Is the experiment still necessary?

Hey Jerry,

Thanks for following up. I mean it seems like most everyone says that the recorded levels from the db meter do not match what the ear will hear and is not a representation of the true flatness of the response (which I won't argue with). I still just don't understand why though and am worried about it, but thats just me wink.gif. I will look into buying a USB mic such that I can join the REW party.
Edited by mjodotcom - 11/5/13 at 6:38pm
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AVS › AVS Forum › Audio › Receivers, Amps, and Processors › "Official" Audyssey thread (FAQ in post #51779)