Are you getting the "THX Reference Level" in the listening position? Do we really need such an output level in our home-theater rooms?

[LightninBoy]

I love watching movies at THX reference level. My system and room easily hit the requisite volume levels. Unfortunately, my family does not share my enthusiasm. I can tell you from experience that Interstellar at THX reference levels is capable of knocking things off shelves in adjoining rooms. Luckily, nothing breakable.

Martin

Happened to us just last week actually, while watching Interstellar. It made a huge racket and scared the bejesus out of the cats.

 

[raistlin65]

It does take some time to soundproof various items if one wants spirited listening levels in their living room without disturbing rattles and buzzes.

There are lots of 1" sq sticky furniture feet pads behind corners of picture frames in my living room. Otherwise, it's like the frames resonate in unison against the walls when my dual 15" ported subs are running. lol

 

[jhwalker]

Just like at my IMAX cinima, I find the reference level playback painfully loud.
I'll normally set my level at -5 db and even -10 db on some loudly mixed movies.
YMMV

The highest volume I can stand is -20. I'm often at -30, which is quite comfortable for me ... though my husband wants the subtitles on at that level

 

[trl]

It really depends on the room. My HT is an open space with wooden walls. I can hit reference levels. but I sit very close (2.3m from centre speaker) My room offers little room gain, so the bass does not pressurise the space like it would in a sealed stone room. Probably also mean I need more subs...

Of course, room does matters a lot, but in the end the THX level is still measured at the same listening point, probably somewhere on a couch or armchair.

 

[trl]

There is no way possible that an SB-1000 can hit reference level down to any meaningful level of extension, nor can a pair, nor can four unless you are in a closet.

I know that in an anechoic room for below 40Hz frequencies the SB-1000 can't pass much beyond 100dB SPL @1m, so probably a total of 5 subs might be needed to get that THX ref. level. Although in my living room, with subs in the corner and for 60Hz (not for 40Hz) there might be a chance to get pretty close to 115dB (I'll probably try to remove the furniture and measure it once).

Here're some measurements for the PB-1000: https://www.soundandvision.com/content/review-svs-pb-1000-subwoofer-measurements that can hit 122.5dB at 63Hz in front of the baffle and both SB and PB share the same 720W-peaks amplifier, so I expect the SB to be few dBs lower than PB at 63Hz. Also, https://www.amazon.com/SVS-SB-1000-Subwoofer-Black-Ash/dp/B00AF88C0M states that SB-1000 can hit 115.4dB and PB can hit 122dB (not sure who and how measured it), so probably it's about the way they measure the sub. With sines it will distort easily, while with music it might get 3-4 dBs higher peaks without hearing the distortions (up to 10% THD probably).

 

[trl]

I will offer a suggestion. I also own an SB-1000 (it is in my bedroom). And I can tell you that in a 25m2 room, you would get some benefit from dual subs that have much better <30hz output. Don't knock it until you try it

I do have two SB-1000 placed at 1m from the corners and walls. The SB-2000 are better below 30Hz, where I need some more "juice", but I'm OK for the moment. Most of the times, for most music, I don't even power up my subs, because my speakers already have very good bass presence due to their 4 x 8" woofers inside (2/pair).

 

[trl]

There are lots of 1" sq sticky furniture feet pads behind corners of picture frames in my living room. Otherwise, it's like the frames resonate in unison against the walls when my dual 15" ported subs are running. lol

When passing 100dB with pink-noise the metallic front-door started to "sing", so I stopped. It was a good thing I had a pair o headphones on my had to not kill my tympanums.

 

[Dimifoot]

Answering to the threads question:

Yes and Yes.

 

[TLEDDY]

The highest volume I can stand is -20. I'm often at -30, which is quite comfortable for me ... though my husband wants the subtitles on at that level

Totally off topic, but I am pleased to find a woman on this Forum!

 

[Koeitje]

Totally off topic, but I am pleased to find a woman on this Forum!

Guys can have husbands...

 

[TLEDDY]

Guys can have husbands...

I am old... that thought, although now a possibility, never even crossed my mind.

Aaaarghhh...

 

[doodlebro]

There is no way possible that an SB-1000 can hit reference level down to any meaningful level of extension, nor can a pair, nor can four unless you are in a closet. I'm in a 2525 ft^3 room and my dual 18" subs with 19mm of rated XMAX just barely squeak out reference level with an REW sine wave sweep down low. Four SB1000's are not equivalent at any frequency to one of my drivers. I cannot hit reference without duals.

It does take some time to soundproof various items if one wants spirited listening levels in their living room without disturbing rattles and buzzes. However, I can listen at *actual* reference level LFE without many distracting rattles and buzzing. I normally don't listen much louder than 10-15 below reference but with subs 6-9 dB hot which results in output right at reference level.

It's also much more challenging for an individual speaker to hit 105 dB peaks at 12'+ listening distance without drastic distortion/clipping/compression. I am perfectly aware that my 91 dB speakers are in no way going to be clean attempting reference level playback, especially when one factors in 3-6 dB of eq necessary below Schroeder. But I'm fine with -10 playback....its the tradeoff I have made in order to have more exceptional music playback.

I also believe that max listening level for movies is often limited by system capability rather than actual SPL. As speakers start to distort/compress/clip the AVR, the sound becomes unbearably loud. My first system with $200 AVR and $150 bookshelf speakers would run you out of the room covering your ears at -10 MV. At a friends theater with full JTR 99dB+ speakers and equally capable subs, reference level was more comfortably clean, clear, impactful and not overly loud. I don't think common low sensitivity speakers driven by AVR's can achieve clean reference level at any normal 10' + distance. I'd bet most speaker/AVR combos will crap the bed before hitting a 95 dB sweep level.

Well said. I am in a small apartment (~700 sqft) and I've turned my system up to -10dB for music at times, but for movies, I find the most "natural" volume to be at -20db. Natural as in, the lowest noises sound reasonably loud and not boosted beyond what is happening on screen. I believe I have recorded peaks as high as 90dB at this volume, from the MLP, using an A-weighted SPL meter.

Can anyone help verify my understanding in the relationship between those peaks and my receiver's settings? My theoretical max for this receiver before clipping my amplifiers would be -5dB, so I guess at -20dB I am 15dB below the reference and would see peaks at 105dB if I were set to -5dB. Does that make sense? I've never been able to figure out how close I am to reference when it sounds "like the theater, but slightly less loud."

I guess for small spaces, 90dB is the tolerable limit for me. I'm sure my neighbors can hear my sub but I haven't had any knocks yet. I guess this is also good news for me since it means my bass response is capable up to this limit, I have a single SB-1000. Will need to upgrade when I'm in a bigger place though!

 

[Costas EAR]

Reference level is the golden standard for me.

I enjoy all movies and audio in general, at reference levels.

I have a Dolby Atmos immersive setup, with 11 pcs of Neumann 310 and 4 sub's, 2 pcs of Neumann 870 with 2 pcs of 10" woofer each, and 2 pcs of genelec sub's, with 2 woofers of 12" at each sub.

Dialogues are in perfect spl, and blasts also sound perfect.

I am using a Trinnov audio possessor.

It is quite difficult to get these spl levels at low frequencies, and room modes need to be addressed.

I measure 0.26 sec for RT 60, and the size of the room is 32 m2.

It is quite expensive to build a high quality atmos setup and to reach the reference levels, no doubt about that, and of course the room has to be well treated.

But it sounds perfect. Absolutely perfect.

 

[hugodlc]

For small room <450 m3 a reference level of 85dB is way to high.
A moderately sized home theater 40m3 will be fine in the range of 78-82dB.
Consider that most Bluray's and DVD'S are mastered for near field monitoring and the level is boosted anywhere from 3 to 6dB or more and especially for the LFE channel.

 

[Blumlein 88]

Well said. I am in a small apartment (~700 sqft) and I've turned my system up to -10dB for music at times, but for movies, I find the most "natural" volume to be at -20db. Natural as in, the lowest noises sound reasonably loud and not boosted beyond what is happening on screen. I believe I have recorded peaks as high as 90dB at this volume, from the MLP, using an A-weighted SPL meter.

Can anyone help verify my understanding in the relationship between those peaks and my receiver's settings? My theoretical max for this receiver before clipping my amplifiers would be -5dB, so I guess at -20dB I am 15dB below the reference and would see peaks at 105dB if I were set to -5dB. Does that make sense? I've never been able to figure out how close I am to reference when it sounds "like the theater, but slightly less loud."

I guess for small spaces, 90dB is the tolerable limit for me. I'm sure my neighbors can hear my sub but I haven't had any knocks yet. I guess this is also good news for me since it means my bass response is capable up to this limit, I have a single SB-1000. Will need to upgrade when I'm in a bigger place though!

Well best way to get a handle on it is to nail down a reference level to go by, even if it isn't THX reference. So play some pink noise in one speaker, and adjust volume it until you get C-wtd levels of 77 db in your case. Or you could use 70 db SPL just as a point to start from. From that and knowing your volume setting you'll be able to work it out with decent precision.

The way you've gone about it we know you are using some -15 db below clipping, but we don't know what SPL clipping is in your room. So we don't know what SPL -15 db setting is for your system. Does that make sense to you?

For instance you may find out your current system can't meet reference levels for THX or Dolby playback and still have 20 db headroom. The idea is movies and such expect 20 db of headroom above an average reference level. In a smaller room that would be something like 77 db SPL. You'll have to measure and see where that leaves you. The input signal should be pink noise at -20 dbFS and see what volume setting gets you 77 db SPL in your room with that signal.

 

[BlackBushBaby]

For small room <450 m3 a reference level of 85dB is way to high.
A moderately sized home theater 40m3 will be fine in the range of 78-82dB.
Consider that most Bluray's and DVD'S are mastered for near field monitoring and the level is boosted anywhere from 3 to 6dB or more and especially for the LFE channel.

That is interesting .You have some more info about that? I have always assumed that when they master for Blue-ray the top gets rolled off( instead of the bass boosted) so that it would translate better to the nearfield. This probably also depends on the studio. (Marvel sounds lame compared too DC).

 

[hugodlc]

Theatrical mixes have a very wide dynamic range that doesn't translate very well for smaller rooms, so big studios usually do a pass on the mix using near field monitors or if possible using a smaller room, so that this mix will sound better in Home theater environments.
There is no set rule as to how much the mix is compressed (if any) as this is done on a mix by mix case, and using ears, and not meters, but if the original was mixed for 85dB reference level and Home theater is more like 78dB, you can gather that the new mix will probably be hotter (louder, and will most likely have a smaller dynamic range) which is good, so the dialogue will not get lost and the explosions will not blow your head off.
Also cinema calibration differs from home theater calibration. Each surround channel level for 5.1 cinema is 82dB and the LFE channel is 95dB.
In Home theater, all channels are referenced to the same level, so they adjust for this in this mastering mix, where they lower the surrounds a hair and boost the LFE to better match the new playback environment.
(As a side note, not every movie/studio does this)
Another important aspect is that the pink noise you use to calibrate your Home Theater is not the same as the one used in dubbing stages, and the frequency content and amplitudes change significantly, so even if your spl meter says 85dB slow, C-weighted, it may not be the same 85 by a couple dB's. But it doesn't matter as long as it sounds good since you're not using your home theater to mix, but to enjoy films.

 

[doodlebro]

Well best way to get a handle on it is to nail down a reference level to go by, even if it isn't THX reference. So play some pink noise in one speaker, and adjust volume it until you get C-wtd levels of 77 db in your case. Or you could use 70 db SPL just as a point to start from. From that and knowing your volume setting you'll be able to work it out with decent precision.

The way you've gone about it we know you are using some -15 db below clipping, but we don't know what SPL clipping is in your room. So we don't know what SPL -15 db setting is for your system. Does that make sense to you?

For instance you may find out your current system can't meet reference levels for THX or Dolby playback and still have 20 db headroom. The idea is movies and such expect 20 db of headroom above an average reference level. In a smaller room that would be something like 77 db SPL. You'll have to measure and see where that leaves you. The input signal should be pink noise at -20 dbFS and see what volume setting gets you 77 db SPL in your room with that signal.

I was assuming (since this is all post Dirac calibrations), that -15dB really is -15dB from the reference level. I just integrated the clipping point piece because I figure my receiver will read the gain from my power amplifier during calibration and adjust levels accordingly. I haven't really messed around with any pink noise yet aside from generating it in REW to test levels before a sweep but I guess I should start.

 

[thepiecesfit]

Can you even have true reference level at home? I mean most of us don't have custom built home theaters and have multi purpose movie watching rooms. A lot of films are also mixed for home use. So if reference level is something that applies to a movie theater then if the source is not the same how can we attain to reach this standard? Is it even realistic?

 

[Sal1950]

Is it even realistic?

Not really an issue, it's a simple matter of absolute volume level and with decent gear and a not overly large room "reference level" can be easily enough to achive. The real question is do you want to listen at that level? I'm a fan of mainly sci-fi, action/adventure and such, and even at the theater like my local IMAX I find the playback level too high. Here at home I rarely run over -10 and often -15. IMO that still gives plenty of punch and impact to the climaxes.