The truth, the whole truth and nothing but... Home Theatre

Guys, you will all naturally agree with me that our search for the perfect hi-fi is a quest for the truth - although interpretations may vary as to what is truth.

I'm wondering about Home Theatre though. I was innocently browsing the Speaker Asylum forum (no one's perfect) when I came across a thread about matching subs to main speakers. It led to an article by a guy called Doug Blackburn in SoundStage. I read the article, disagreed with much of it, agreed with some. At the end there was a link to a matching article about subs for Home Theatre in Home Theatre Sound. I read this too.

Now as you know I don't know all there is to know in the field of Home Theatre, although I'm learning. However, this paragraph (detailing differences between the requirements for HT and music subs) stuck in my throat:

... Home-theater subwoofers require a boost in output in the 40-80Hz range to make effects seem real and solid. (Why this is not encoded on the DVDs themselves is beyond me. If the DVDs simply had the boost encoded where it is needed, one subwoofer could serve for both music and movies.) Subwoofers for music need linear response from around 20Hz up to 160-200Hz. Surprisingly, movies are not that dependent on response below 40Hz or so. When there is sub-40Hz content in the soundtrack, there seems to be some built-in augmentation to make those frequencies heard and felt, even on subwoofers that have a hard time going that low. DVD soundtracks played back on music subwoofers with linear frequency response sound a bit restrained and lack the impact and serious amounts of air, floor, and wall motion that home-theater subwoofers can generate. (from an article by Doug Blackburn)

So here are my questions...

Are the requirements for music and HT subs really different?
Should HT subs be 'less than honest' in the 40-80Hz range?

 

Home theatre is an abomination which has no place on a hi-fi forum.

Burn them all, I say.

 

That's funny Bub, a few round here would say the same about you !

 

IMHO virtually all HT subs, can't cut the mustard with 2 channel, there are a couple of exceptions though.
Prehaps a 2 designs are required, ultising the same power pack, one tuned for depth charges ala' U571 and Die another day protnectics and the other for good old Malhar and Motorhead

 

I guess with movies a lot of the bass that people care about is for explosions and other effects, for which most peoples experience of what is realistic is rather limited? So just boost that and everything feels more impressive which is what really matters here?

My parents have a pretty cheap HT setup, with I think an Energy Take 5.1 speaker setup. Whatever, for films the sub seems to add a pleasing 'thump' to explosions etc, but with music it sounds truly terrible. No doubt a combination of being a very poor sub and not being set up to it's full potential.

 

I've heard this so often that it's difficult to believe that it ain't true. The fact is though that I watch loads of films and I'd estimate only about 1 in 10 have explosions (and maybe 1 in 5,000 have earthquakes).

Great though they may be, there are movies other than James Bond and Star Wars.

 

But you don't gain much from a full 5.1 (or greater) system with those imho of course. If you watch a film that is almost exclusively dialogue driven then a really decent mono system would please more than the same budget spread 8 ways, again imho.

Cheers

Jason

 

THe obvious approach would be to design a linear sub with some kind of HT EQ switch that can be engaged for movies and the like.

 

Or stereo, Jason, of course. All films have music.

Still, that's a separate issue. My question is about the subs.

 

I don't think the requirements are different and certainly don't buy the suggestion that HT subs should be less than honest in the 40-80Hz range.

There aren't, IMO, HT subs and music subs - there are brilliant, good and bad subs and lots of others in between. What there is, I would say, is more of an acceptance of poor subs in the HT community - many are less picky, happy if the sub rattles the floor-boards and not caring if it's mainly harmonic distortion that's causing the room to shake.

Take the best subs around e.g. B&W ASW850, Velodyne DD series - they play cleanly right through their frequency range - there's no 'less than honest' augmentation going on in the 40-80Hz range.

What the top subs do, which most can't, is play the deep stuff cleanly at high volumes. And, if they can play 20Hz as clean as a whistle then reproducing most musical content cleanly is a stoll in the park. In other words, a sub that is superb with HT should be nigh on perfect with music.

Conversely, a sub that is good with music (where there's generally not a great deal going on below 40Hz) can quite easily get into all sorts of trouble when asked to play 20Hz at loud volumes.

Matt.

 

It's all a matter of taste. Articles like that assume all HT enthusiasts to be after the biggest, loudest, boomiest, most impressive HT system they can get their hands on. This just isn't true. Personally, I like my home theatre to be as clean and realistic as my hifi, which means no silly boosted bass. In fact, HT systems with bass boosted like this tend to get on my nerves very quickly. And I'm not alone (honest!)

I think part of the problem is that a lot of HT enthusiasts want to recreate that "cinema sound" with their own system - and sadly the vast majority of cinemas have big, boomy, boosted bass to impress the punters. This is what people come to expect from cinemas, and for some people, this is what they want at home.

Dunc

 

You're absolutely right Dunc. It's the same with some quite expensive car stereo systems where the factory settings are ridiculously bass heavy.

It's a question of dealing with peoples' expectations and it's a question of education. If you talked about 'truth' in the context of hi-fi systems, let alone Home Theatre, most people wouldn't have the faintest idea what you were talking about.

 

I agree with the scaffold bloke,Home Cinema is shit.Its not Home Cinema,its home DVD with a small tele and 4 speakers than get in the way and an sub and amp that wont fit anywhere and piss teh wife off everyday.Its good for loud bangs,but in fact you can never have the thing on loud enough to get the benefit from the loud bangs,due to kids and neighbours.
Obviously single blokes who don'y live in London and have a detached house and no wife and a dedicated listening room,fair enough,but for everyone else,stay with Nicam and a cheapo DVD,the rest is just arse.A 32" Stereo TV with a £100 Asda DVD is perfectly sane.

 

I think £100's a bit steep for the Asda, Saab.

 

Toshibsa SD330E - £53 from Richers! Now you're talking!

 

i'm thinking of manufacturing a range of speakers and using internet forums as a cheap way of marketing them

 

The requirements for HT and ICE are totally different to HiFi, which is why I find it difficult to understand why people keep slapping subs onto their HiFi.

One reason that car stereos need to be ridiculously bass heavy is that road noise tends to drown out low frequencies (and of course the baseball cap restricts the flow of blood to the brain).

 

been done

 

Matt,

I think you will find that the Velodynes offer a contour control designed to boost the 40hz range for maximum theatrical impact. They can of course bypass this on other eq settings designed for music replay.

Hifi is not, IMO, about poxy little speakers incapable of proper bass reproduction - although people unfamiliar with true hifi would be excused for not realising this.

 

Is it a problem?

That is the whole point of HT. To reproduce the audio experience that you can get in a cinema. If the cinemas have big boomy bass then so should a HT system. That is the whole point of HT systems, to reproduce the cinema sound accurately, NOT accurately reproduce the sounds as they should be, (what ever that may be). However, it is obviously the case that many cinema sound systems have just been set up as the guy installing them thought they should sound. There was no objective measure of how to set up the sound in a cinema. That is why THX was introduced to enable a standard to be set. So that cinema goers could be confident that they are hearing the sound track as the producer/director of the film intended not how some cinema audio installation engineer thinks it should sound.

GTM