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post #66811 of 70885
Quote:
Originally Posted by comfynumb View Post
 
Quote:
Originally Posted by kbarnes701 View Post

You can understand it. You understand that it is not correct smile.gif



Again Keith all I said was there are different ways to get to reference. You are obviously sticking up for your buddy here which I can understand but no need to keep putting words in my mouth that I never said.

 

Is this an attempt at irony?

post #66812 of 70885
Quote:
Originally Posted by kbarnes701 View Post

Now you have simply stopped reading, so I will stop writing after this post.

The fact you don't grasp the relationship between speaker size and sensitivity wrt to playing bass reveals your lack of understanding of the subject and shows that you do not "get the sensitivity thing". 

And saying you "like the more wattage route" continues the revelation that you have still not grasped what I am saying. For starters, more wattage is totally pointless unless the wattage is required in order to make the speakers play at a certain SPL. A 10 watt amp is as good as a 500 watt amp if the former can enable reference to be attained. And the second point you keep missing is that more wattage is also pointless if the speaker cannot handle it. And the final point is that if the speaker sensitivity is low, and the power handling not sufficiently high, then the speaker will simply be incapable of playing at reference anyway.

As you believe this is "jumping down your throat" and as you have started attributing things to me that I never said and saying it was "not the best idea" to have said the things I never said, and as you aren't really listening anyway, I will stop posting on this topic now.



What's not to understand about sensitivity? It's common knowledge your not getting what I'm saying and I'm not getting your point either. Let's leave it at that and they make both kind of speakers for people they like them.
post #66813 of 70885
There is no doubt many speakers sound better when putting more juice to them. My PSB Golds did not wake up until I put 400 WPC into them, this had been stated in many of the PSB reviews of them also. I've been at this for a long time and just because I'm an Audyssey newbie does not mean I'm an AV newbie. Time to move on.


Edit;
Keith I also didn't mean to ruffle your feathers with any of my commenters, so if I did I apologize. You've always been helpful to me and I appreciate it.
Edited by comfynumb - 11/9/13 at 10:58am
post #66814 of 70885
Quote:
Originally Posted by comfynumb View Post

There is no doubt many speakers sound better when putting more juice to them. My PSB Golds did not wake up until I put 400 WPC into them, this had been stated in many of the PSB reviews of them also. I've been at this for a long time and just because I'm an Audyssey newbie does not mean I'm an AV newbie. Time to move on.

 

This is a different topic so I will comment. That is just 'audiophile' nonsense I'm afraid, so in fact far from being 'no doubt' there is considerable doubt. The amount of power 'put into' a speaker is entirely related to the sound output required from the speaker. So if the speaker needs xx watts to generate yy SPL without clipping then that is it. End of. So long as the amp can cleanly generate xx watts, then it is all that is required. Having a far more powerful amp and 'leaving the additional watts on the table', ie unused, serves no purpose at all. None. As in zero. 

 

If you pumped 400 watts into the PSB Golds then, for that amount of power, they would have generated a known and quantifiable SPL. Are you saying that those speakers were no use unless you played them at that SPL? I don't think so. If you mean you believed you needed a 400 watt amp to make them 'wake up' even though you were only using, say, 100 watts of the available power, surely you can see that the unused power cannot possibly have any bearing whatsoever on the sound produced by the speakers?

 

 

Quote:

 Edit;
Keith I also didn't mean to ruffle your feathers with any of my commenters, so if I did I apologize. You've always been helpful to me and I appreciate it.

 

No - nothing here was ruffled, so no need to apologise :)

post #66815 of 70885
Quote:
Originally Posted by comfynumb View Post

There is no doubt many speakers sound better when putting more juice to them. My PSB Golds did not wake up until I put 400 WPC into them, this had been stated in many of the PSB reviews of them also. I've been at this for a long time and just because I'm an Audyssey newbie does not mean I'm an AV newbie. Time to move on.


Edit;
Keith I also didn't mean to ruffle your feathers with any of my commenters, so if I did I apologize. You've always been helpful to me and I appreciate it.
You don't seem to understand what Keith is telling you.

It's a lot easier for high sensitivity speakers to produce high SPLs than with lower sensitivity speakers. A 3db difference takes DOUBLE the power.

You said you're using PSB Stratus Gold Mains? You do realise that they're rated 88db/w/m with a power handling of 300 watts? It would take 451 watts to hit 105db 10 feet away, or 800 watts to hit 105db at 13 feet away. It wouldn't matter if you used 1000 watt monoblocks, as the speakers can't handle it.

The Boston Acoustics E100's that I used to use for Mains at 89db/w/m and a 400 watt power handling were one of the highest power handling ratings I've seen at those sensitivities. At 358 watts to hit Reference at 10 feet and using 500 watt monoblocks, I was on the edge to attain Reference levels at my MLP. Although compression tests indicated that they could do it, I elected to get 95db/w/m speakers to allow further seating distances.

If you were using 91db sensitivity speakers for example, it would only take 225 watts to hit Reference at 10 feet. 95db/w/m speakers would only need 90 watts.

The simple truth is, most lower sensitivity speakers just can't handle the power input it would take to produce THX Reference levels at typical listening distances, whereas high sensitivity speakers don't take much power at all to hit the same SPLs.

Take Gooddoc's Noesis 212HT speakers for instance. JTR made them as a home version of their commercial speakers with high sensitivity (101db/w/m) and very high power handling (2000 watts). Those speakers only need 23 watts to hit Reference at 10 feet. You wouldn't really need 2000 watts unless you were trying to hit Reference from 70-80 feet away (and the reviews indicate that just 2 of the commercial versions of those is enough for a small hall, when mated to enough subs).


Max
post #66816 of 70885
Hi all,

I have been trying to follow this discussion, and becoming more and more confused (actually, confusing myself when trying to collate all of it). My HT setup is nowhere in the same league as those here, but I am trying to apply what I am learning. To give my questions some context, my setup is as follows:

Mains: Infinity Alpha 50 towers (@11')
Center: Infinity 37c (@10')
Surrounds: Infinity Primus 150 bookshelfs (@4')
Subs: Dual SVS PC13 Ultra cyliders (@15', flanking the mains)
AVR: Denon 2311ci

I just recalibrated via Audyssey due to a furniture replacement, and double-checked the SPL (via a calibrated Galaxy 140 meter) and Disney WOW. What I found was that the satellites were at the expected 75dB, but the LFE was at 85dB. My understanding is that THX reference standards are for 105dB/115dB for the sats/LFE, and with the -30dBSF offset that gives the 75dB/85dB I am seeing. Is that even remotely correct? From earlier this year,
Quote:
Originally Posted by batpig View Post

During calibration the sub channel is trimmed to 75db at 30dbfs just like the other channels, not 85db. If you send a pure LFE signal at 30dbfs then it will play it at 85db.

I read the first sentence as contradictory to the second, but that just shows my lack of understanding, not inaccuracy of the statement...

Next, I get that movie soundtracks are mixed to THX reference, so I should be able to set my MV at a given place and get the same relative volume from everything, right? Except I have found that different movie soundtracks are optimal (to my ears) at different levels (I listen at -10 to -20dB below reference). I even keep a database of optimal MV settings for each movie (set the first time I watch them). What am I doing wrong?

Thanks for all the great reading!
Edited by Vader424242 - 11/9/13 at 12:21pm
post #66817 of 70885
Subwoofer rookie

I am going run Audyssey. It tells me to turn the subwoofer volume up. Is "-30" up or do I set it closer to "0" or some other number?

Thanks,

Jim
post #66818 of 70885
Quote:
Originally Posted by djbluemax1 View Post

You don't seem to understand what Keith is telling you.

It's a lot easier for high sensitivity speakers to produce high SPLs than with lower sensitivity speakers. A 3db difference takes DOUBLE the power.

You said you're using PSB Stratus Gold Mains? You do realise that they're rated 88db/w/m with a power handling of 300 watts? It would take 451 watts to hit 105db 10 feet away, or 800 watts to hit 105db at 13 feet away. It wouldn't matter if you used 1000 watt monoblocks, as the speakers can't handle it.

The Boston Acoustics E100's that I used to use for Mains at 89db/w/m and a 400 watt power handling were one of the highest power handling ratings I've seen at those sensitivities. At 358 watts to hit Reference at 10 feet and using 500 watt monoblocks, I was on the edge to attain Reference levels at my MLP. Although compression tests indicated that they could do it, I elected to get 95db/w/m speakers to allow further seating distances.

If you were using 91db sensitivity speakers for example, it would only take 225 watts to hit Reference at 10 feet. 95db/w/m speakers would only need 90 watts.

The simple truth is, most lower sensitivity speakers just can't handle the power input it would take to produce THX Reference levels at typical listening distances, whereas high sensitivity speakers don't take much power at all to hit the same SPLs.

Take Gooddoc's Noesis 212HT speakers for instance. JTR made them as a home version of their commercial speakers with high sensitivity (101db/w/m) and very high power handling (2000 watts). Those speakers only need 23 watts to hit Reference at 10 feet. You wouldn't really need 2000 watts unless you were trying to hit Reference from 70-80 feet away (and the reviews indicate that just 2 of the commercial versions of those is enough for a small hall, when mated to enough subs).


Max

I run my E100's on a parasound Halo A21 and it delivers reference cleanly at only 250 watts a channel , I notice you guys are falling to discuss other factors on amps besides watts , such as current capability and damping and not to mention 105db is a peak not a sustained level of playback and most amps have headroom for this.I do plan on running a pair of Halo JC1's (mono blocks) one day as the 400watts a channel plus that last degree I hope of refinement will be my last amps to buy but as it stands the A21 delivers the goods and handles the E100's without compression and delivers shocking dynamics when needed wink.gif
post #66819 of 70885
Quote:
Originally Posted by Vader424242 View Post

Hi all,

I have been trying to follow this discussion, and becoming more and more confused (actually, confusing myself when trying to collate all of it). My HT setup is nowhere in the same league as those here, but I am trying to apply what I am learning. To give my questions some context, my setup is as follows:

Mains: Infinity Alpha 50 towers (@11')
Center: Infinity 37c (@10')
Surrounds: Infinity Primus 150 bookshelfs (@4')
Subs: Dual SVS PC13 Ultra cyliders (@15', flanking the mains)
AVR: Denon 2311ci

I just recalibrated via Audyssey due to a furniture replacement, and double-checked the SPL (via a calibrated Galaxy 140 meter) and Disney WOW. What I found was that the satellites were at the expected 75dB, but the LFE was at 85dB. My understanding is that THX reference standards are for 105dB/115dB for the sats/LFE, and with the -30dBSF offset that gives the 75dB/85dB I am seeing. Is that even remotely correct? From earlier this year,

 

Hi - when you say you used your SPL meter to check, do you mean that after calibration you played the AVR test tones and then measured the level of the tones from the MLP?  If so then yes, you should read 75dB for all channels, as this was the calibrated level. The test tones, however, bypass Audyssey so if Audyssey had to make considerable FR adjustments, it is possible that the levels when bypassing Audyssey are different to those achieved when Audyssey is engaged. But if you also used an external source of tones, then these would take account of the audyssey calibration anyway. I have found that my meters aren't very accurate in the bass region so I generally ignore any readings for the subs. All our experience shows that Audyssey is pretty good at calibrating levels, so I would always tend to believe Audyssey rather than my meters, even though I have excellent software meters and a fairly expensive, calibrated mic.

 

Quote:

 Next, I get that movie soundtracks are mixed to THX reference, so I should be able to set my MV at a given place and get the same relative volume from everything, right? Except I have found that different movie soundtracks are optimal (to my ears) at different levels (I listen at -10 to -20dB below reference). I even keep a database of optimal MV settings for each movie (set the first time I watch them). What am I doing wrong?

 

Nothing probably. Reference doesn't mean all movies will sound as loud as all others. It just means that the average level through the movie is 85dB and peaks should not exceed 105dB or 115dB for the LFE channel. A quiet movie such as a dialogue-driven drama will not sound as loud as a full-on action movie. And even some action movies will sometimes sound louder than others - for example The Dark Knight is an incredibly loud movie - I am not sure if this is because the average of 85dB is achieved more or less all the time during the movie (85dB is actually pretty loud) or if the movie has actually been mixed at higher than Reference levels (which would surprise me). 

 

I also believe that Dolby's Dialog Normalization feature has a bearing on this but my understanding if Dialnorm is sketchy and changes every time I read about it, so ICBW on that.

 

I typically aim to listen on my system at -6dB but I find that with some movies I need -3dB and with others -9dB. I don't worry about it much - I tend to set each movie to a level where dialogue sounds natural and then leave it there for the entire movie.

 

Do you use Dynamic EQ?  If so, that will also impact on perceived loudness, especially of the bass. I assume you are not using stuff like Dynamic Volume as this compresses the range of sounds (softest to loudest) and gives the impression of sounds sounding more similar to each other whether loud or soft (IOW it compresses the dynamic range of the material).

 

Perhaps others will chime in with their views?

post #66820 of 70885
Quote:
Originally Posted by kbarnes701 View Post

No - nothing here was ruffled, so no need to apologise smile.gif

Quoted the wrong info but. Keith is right. If you listen at -20 (a volume most of us would put on as background music) then you could use a tiny amp for just about any speaker. Take your 1 watt at 1 meter measurement from your manufacturer. You lose 3db per meter of distance. You then double amp power for every 3db. 1,2,4,8,16,32,64...
To be honest I thought the same way for a bit. But i was quickly corrected and now hold the same perspective. I thought my 4k Sherbourn PA 7350 amp made the sound different but after placebo wore off I saw the light. There is a valid discussion with having headroom for dynamics and such. But if you are pumping 400 watts into a speaker you probably wouldn't want to be in the same room due to SPL unless it was a dull sensitive speaker and you had a huge room. smile.gif
post #66821 of 70885
Quote:
Originally Posted by tiguej View Post

Subwoofer rookie

I am going run Audyssey. It tells me to turn the subwoofer volume up. Is "-30" up or do I set it closer to "0" or some other number?

Thanks,

Jim

 

On the back of your sub there is a knob called 'gain' or 'volume' or similar. Turning the knob in a specific direction (usually clockwise) will make the sub louder. That is what they mean when they say to turn the sub volume up. It's a pre-check to set the sub to the right level so that when Audyssey runs it calibrates the sub trim to be somewhere in the middle of its range rather than at the extremes.

 

If your sub gain control is marked -30 to 0, then 0 is the loudest. If you currently have it set to, say, -15 and it is asking you to turn the volume up, you need to to -10 or whatever - towards 0 anyway.

 

If 0 is the loudest the sub can play, then -30 is, for example, 30dB below 0. So -10 is only 10dB below 0, hence louder. Have I explained this clearly? 

post #66822 of 70885
Quote:
Originally Posted by kbarnes701 View Post

No - nothing here was ruffled, so no need to apologise smile.gif



No they played well with my old Denon receiver but they just were power hungry and seemed to play better with a higher powered amp. Of course I might like my music abnormally loud on occasions biggrin.gif
post #66823 of 70885
Quote:
Originally Posted by djbluemax1 View Post

You don't seem to understand what Keith is telling you.

It's a lot easier for high sensitivity speakers to produce high SPLs than with lower sensitivity speakers. A 3db difference takes DOUBLE the power.

You said you're using PSB Stratus Gold Mains? You do realise that they're rated 88db/w/m with a power handling of 300 watts? It would take 451 watts to hit 105db 10 feet away, or 800 watts to hit 105db at 13 feet away. It wouldn't matter if you used 1000 watt monoblocks, as the speakers can't handle it.

The Boston Acoustics E100's that I used to use for Mains at 89db/w/m and a 400 watt power handling were one of the highest power handling ratings I've seen at those sensitivities. At 358 watts to hit Reference at 10 feet and using 500 watt monoblocks, I was on the edge to attain Reference levels at my MLP. Although compression tests indicated that they could do it, I elected to get 95db/w/m speakers to allow further seating distances.

If you were using 91db sensitivity speakers for example, it would only take 225 watts to hit Reference at 10 feet. 95db/w/m speakers would only need 90 watts.

The simple truth is, most lower sensitivity speakers just can't handle the power input it would take to produce THX Reference levels at typical listening distances, whereas high sensitivity speakers don't take much power at all to hit the same SPLs.

Take Gooddoc's Noesis 212HT speakers for instance. JTR made them as a home version of their commercial speakers with high sensitivity (101db/w/m) and very high power handling (2000 watts). Those speakers only need 23 watts to hit Reference at 10 feet. You wouldn't really need 2000 watts unless you were trying to hit Reference from 70-80 feet away (and the reviews indicate that just 2 of the commercial versions of those is enough for a small hall, when mated to enough subs).


Max



Max I get it! I can also promise you my setup will produce THX levels at the MLP and higher biggrin.gif read up on the Golds they can handle many times their rated power.
At one time I used the Golds but my mains are Revel F-52's and my ears tap out at about +4
post #66824 of 70885
Quote:
Originally Posted by kbarnes701 View Post

Hi - when you say you used your SPL meter to check, do you mean that after calibration you played the AVR test tones and then measured the level of the tones from the MLP?

Hi Keith,

I checked both ways: first with the internal test tones, which did indeed read at 75dB (both sats and LFE). It was when I used the external source (Disney WOW) that I found the 75dB/85dB discrepancy.

Quote:
Do you use Dynamic EQ? If so, that will also impact on perceived loudness, especially of the bass. I assume you are not using stuff like Dynamic Volume as this compresses the range of sounds (softest to loudest) and gives the impression of sounds sounding more similar to each other whether loud or soft (IOW it compresses the dynamic range of the material).

I am not using any compression algorithms (I like my dynamic range...smile.gif) As for DynamicEQ, I am going back and forth as to if I like the effect (right now, I have it turned off). I ran a sweep using REW and looked at what it did, and I'm not sure if I like the boosting it does (it saps my headroom, and I have read that some have problems with chuffing being caused by DEQ). Here are the results...


Edited by Vader424242 - 11/9/13 at 1:35pm
post #66825 of 70885
What you are missing is a common mistake, conflating the "subwoofer channel" with the LFE channel. LFE is a discrete channel on the source, which is boosted 10db in the processor by design. The subwoofer channel itself plays both LFE and redirected bass from other channels (which doesn't get a 10db boost).

So there isn't anything contradictory about saying the sub is calibrated to 75db at 30dbfs, but a 30dbfs LFE tone from an external calibration disc should play at 85db. It's because full scale for the LFE channel is 115db instead of 105db.

It's key to understand the differences between LFE channel and subwoofer channel. I'm on my phone so hard to link but google "misunderstood LFE" and you will find a really good article on the topic.
post #66826 of 70885
Quote:
Originally Posted by batpig View Post

What you are missing is a common mistake, conflating the "subwoofer channel" with the LFE channel.
If you refer to it as a subwoofer "output", the semantics are easier when making the distinction with the LFE channel (which really is a channel).
post #66827 of 70885
Quote:
Originally Posted by Vader424242 View Post

I just recalibrated via Audyssey due to a furniture replacement, and double-checked the SPL (via a calibrated Galaxy 140 meter) and Disney WOW. What I found was that the satellites were at the expected 75dB, but the LFE was at 85dB. My understanding is that THX reference standards are for 105dB/115dB for the sats/LFE, and with the -30dBSF offset that gives the 75dB/85dB I am seeing. Is that even remotely correct?
It is true that the WOW disc has the LFE recorded such that it will nominally produce a much higher SPL from the LFE than the main channels. In fact, all the channels on that disc are higher than normal discs and normal processor test tones, which are set for 75 dB.

The WOW disc reads 85 dB in the main channels and 95 dB (give or take due to EQ and crossovers) in a calibrated system. Not sure why it was made that way, but there it is.

Dolby and THX established 75 dB as the home calibration reference. That is a signal recorded at -30 dBFS in the main channels, and -40 dBFS in the LFE channel. The WOW disc recorded all the signals at -20 dBFS, incl LFE. Silly.
post #66828 of 70885
Quote:
Originally Posted by batpig View Post

What you are missing is a common mistake, conflating the "subwoofer channel" with the LFE channel. LFE is a discrete channel on the source, which is boosted 10db in the processor by design. The subwoofer channel itself plays both LFE and redirected bass from other channels (which doesn't get a 10db boost).

So there isn't anything contradictory about saying the sub is calibrated to 75db at 30dbfs, but a 30dbfs LFE tone from an external calibration disc should play at 85db. It's because full scale for the LFE channel is 115db instead of 105db.

It's key to understand the differences between LFE channel and subwoofer channel. I'm on my phone so hard to link but google "misunderstood LFE" and you will find a really good article on the topic.

 

post #66829 of 70885
Thank you all! It is starting to sink in, and make perfect sense. smile.gif
post #66830 of 70885
Quote:
Originally Posted by Roger Dressler View Post

Quote:
Originally Posted by Vader424242 View Post

I just recalibrated via Audyssey due to a furniture replacement, and double-checked the SPL (via a calibrated Galaxy 140 meter) and Disney WOW. What I found was that the satellites were at the expected 75dB, but the LFE was at 85dB. My understanding is that THX reference standards are for 105dB/115dB for the sats/LFE, and with the -30dBSF offset that gives the 75dB/85dB I am seeing. Is that even remotely correct?
It is true that the WOW disc has the LFE recorded such that it will nominally produce a much higher SPL from the LFE than the main channels. In fact, all the channels on that disc are higher than normal discs and normal processor test tones, which are set for 75 dB.

The WOW disc reads 85 dB in the main channels and 95 dB (give or take due to EQ and crossovers) in a calibrated system. Not sure why it was made that way, but there it is.

Dolby and THX established 75 dB as the home calibration reference. That is a signal recorded at -30 dBFS in the main channels, and -40 dBFS in the LFE channel. The WOW disc recorded all the signals at -20 dBFS, incl LFE. Silly.
Thanks for that info Roger. I was about to suggest the poster head to the WOW Review thread to check/confirm what levels the WOW tones were recorded at.


Max
post #66831 of 70885
Quote:
Originally Posted by kbarnes701 View Post

Agreed in general  - more sensitive speakers are a good route to follow. But wrt to 89dB/w/m, that is the exact sensitivity of my M&K S150s which are THX certified, which means they are guaranteed to play at Reference at the seating position. It depends on the power handling capabilities of the speakers as much as anything and the S150s can handle sufficient power to 'hit the mark' - their multiple array tweeters and dual drivers are important in this regard. But yes, often the problem with insensitive speakers is that they also cannot handle enough power to ever stand a chance of hitting Reference - so sensitive speakers are easier to work with and also provide a cheaper amp option as you say.

Are those M&K's the active version or passive? How much power are they using to reach those levels at your seating distance?

I've been using THX PM3 certified (meets the same standards as consumer Ultra2) Mackie HR824's and 624's for many years. The 624's are about 4.5ft. from my seating distance due to the distance to the sidewalls.The 824's are 6ft. from my seating distance.All are positioned at the standard 5.1 ITU angles on stands and I have them in a pretty small room.I really like the Mackies.Their spec's are very good for a speaker of their size. They are really only meant to meet their rated output at around 3ft./1m though.
Quote:
Originally Posted by batpig View Post

89db sensitive speakers isn't a great recipe for true reference playback unless you are pretty close to the speakers. If you only want to get to -10 or even -5 it's ok but those last few db are a doozy thanks to exponential power demands. You could jump from needing ~25-30 w/ch at -10 to needing ~250-300 w/ch at reference. Plus even if you have enough power you could run into compression. But it's probably only going I manifest during peaks.

Move to 92db speakers and you only need half the power. Much cheaper route in most cases. (BtW these are general thoughts, not criticizing you).

My typical MV level for movies is around -13 to -11db below reference volume. As long as I listen no louder than those levels I think I should be relatively fine with the speakers I'm using.
post #66832 of 70885
Quote:
Originally Posted by StevenLansing View Post
 
Quote:
Originally Posted by kbarnes701 View Post

Agreed in general  - more sensitive speakers are a good route to follow. But wrt to 89dB/w/m, that is the exact sensitivity of my M&K S150s which are THX certified, which means they are guaranteed to play at Reference at the seating position. It depends on the power handling capabilities of the speakers as much as anything and the S150s can handle sufficient power to 'hit the mark' - their multiple array tweeters and dual drivers are important in this regard. But yes, often the problem with insensitive speakers is that they also cannot handle enough power to ever stand a chance of hitting Reference - so sensitive speakers are easier to work with and also provide a cheaper amp option as you say.

Are those M&K's the active version or passive? How much power are they using to reach those levels at your seating distance?

 

Mine are passive. IDK how much power they use to reach Reference, but they are powered with (rated) 300 watts each channel (likely more on peaks I’d guess). The Crown calculator shows that is enough at my seating distance:

 

 

When I set the MV to 0dB and take a reading with my SPL meter, I see peaks of 105dB (and sometimes more - probably due to inaccuracies in the meter?). 

 

Quote:

 I've been using THX PM3 certified (meets the same standards as consumer Ultra2) Mackie HR824's and 624's for many years. The 624's are about 4.5ft. from my seating distance due to the distance to the sidewalls.The 824's are 6ft. from my seating distance.All are positioned at the standard 5.1 ITU angles on stands and I have them in a pretty small room.I really like the Mackies.Their spec's are very good for a speaker of their size. They are really only meant to meet their rated output at around 3ft./1m though.
 

 

AIUI, THX specs require that Reference is attainable at the listening distance specified for the THX rating (Ultra 2, Select 2 etc). This is what it says on the THX website:

 

THX Ultra2THX Ultra2

THX Ultra2 Certified products bring the cinematic experience to larger home theaters, 3,000 cubic feet in size, with a viewing distance of 12 feet or greater from the screen.

 

THX Select2THX Select2

THX Select2 Certified products are for medium sized rooms, up to 2,000 cubic feet in size, with a 10-12 foot viewing distance from the screen.

 

It doesn't specifically state there that they are meaning Reference levels, but it is clear from other information on the site that this is what they do mean.

 

In general, I think all that matters is that a system can meet the SPL requirements of the user of that system, cleanly, without clipping and without endangering the equipment itself. If a system can do that, then no more is required of it. I typically listen at about -5dB and the Crown calculator shows that I need 68 watts for that (chickenfeed).

 

 

Even with 3dB headroom I'd only need 136 watts, which is easily attainable here.

 

 

EDIT: In my original post, quoted above, I mistakenly gave the sensitivity of my speakers as 89dB - on checking it turns out to be 90dB.


Edited by kbarnes701 - 11/10/13 at 8:28am
post #66833 of 70885
Greetings

I'm wondering if there is something wrong with my mic, because this has never happened before, until recently.

My sub is right behind the MLP and when it comes time to run the sub measurement test, Audyssey XT has to run the test time over again a couple times or even 3x. Each time the test gets significantly louder, but yet it sets the sub trim level at -3.

The rest of the measurements are as follows:

FL -2 10.1 ft
C - 3 9.6 ft
FR -2 10.1 ft
SL -2 7.6 ft
SR -2 7.6 ft
SW -3 7.0 ft

Does everything look Ok?

I must have run Audyssey at least 20x in the past because I have been adjusting sub and speaker positions. Up until now it never had to test the sub with a louder test tone.
post #66834 of 70885
This would indicate the sub signal is not being heard by the mic which is why the signal is raised to subsequently higher volume levels, however, the final results are normal. smile.gif
post #66835 of 70885
Quote:
Originally Posted by JasonT35 View Post

Greetings

I'm wondering if there is something wrong with my mic, because this has never happened before, until recently.

My sub is right behind the MLP and when it comes time to run the sub measurement test, Audyssey XT has to run the test time over again a couple times or even 3x. Each time the test gets significantly louder, but yet it sets the sub trim level at -3.

The rest of the measurements are as follows:

FL -2 10.1 ft
C - 3 9.6 ft
FR -2 10.1 ft
SL -2 7.6 ft
SR -2 7.6 ft
SW -3 7.0 ft

Does everything look Ok?

I must have run Audyssey at least 20x in the past because I have been adjusting sub and speaker positions. Up until now it never had to test the sub with a louder test tone.

 

It all looks OK. If Audyssey has to re-chirp it means that ambient noise is higher than expected, or more accurately the SNR required for calibration is not being met, which in turn could mean the sub is simply too quiet. There is no harm in turning up the gain on the sub itself a little next time you run Audyssey. This will probably negate the need for Audyssey to re-chirp and it will result in a trim setting of maybe -5 or -7 or whatever (depending on how far you turn up the sub gain). But there is nothing wrong at all with a sub trim of -3.

 

Incidentally, I am suspicious of why Audyssey needed to re-chirp the sub this time if it hasn't had to in the past. Are you sure that you haven't moved the sub into a null in the room?

post #66836 of 70885
I thought so but just wanted to make sure. Thanks guys
post #66837 of 70885
Quote:
Originally Posted by kbarnes701 View Post


EDIT: In my original post, quoted above, I mistakenly gave the sensitivity of my speakers as 89dB - on checking it turns out to be 90dB.



I think one thing to consider is that the manufacturers specs are not always what the actual measured specs are. My speakers sensitivity from the manufacturers specs are 87.5db when tested by S&V they said they were 88db. In our rooms how do we measure that or doesn't it change?

This seems to be a better guide that takes our room (at least partially) into consideration. Here is what it came up with for my room. No crazy numbers like 1,000 WPC to achieve listening levels of nearly 110db at the 9.7' LP.


http://myhometheater.homestead.com/splcalculator.html



Edited by comfynumb - 11/10/13 at 7:39am
post #66838 of 70885
kbarnes701

Perfect. Thanks for the feedback. I was turning it the wrong way.

Jim
post #66839 of 70885
Quote:
Originally Posted by comfynumb View Post
 
Quote:
Originally Posted by kbarnes701 View Post


EDIT: In my original post, quoted above, I mistakenly gave the sensitivity of my speakers as 89dB - on checking it turns out to be 90dB.



I think one thing to consider is that the manufacturers specs are not always what the actual measured specs are. My speakers sensitivity from the manufacturers specs are 87.5db when tested by S&V they said they were 88db. In our rooms how do we measure that or doesn't it change?

This seems to be a better guide that takes our room (at least partially) into consideration. Here is what it came up with for my room. No crazy numbers like 1,000 WPC to achieve listening levels of nearly 110db at the 9.7' LP.


http://myhometheater.homestead.com/splcalculator.html


 

As my speakers have to meet a certain spec in order to gain their THX certification, I would assume that their spec tolerances are extremely tight.

 

I prefer the Crown SPL calculator these days as it is more conservative than some of the others, so it gives a 'safety margin'. The only real way to test the SPL of course is in the actual room.

post #66840 of 70885
Quote:
Originally Posted by tiguej View Post

kbarnes701

Perfect. Thanks for the feedback. I was turning it the wrong way.

Jim

 

Cool! 

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