Acoustics Interviews Part 1: Kal Rubinson

[Audioholics]

Acoustics Interviews Part 1, 2 and 3: Kal Rubinson, John Atkinson, Michael Fremer

Rives Audio conducted some interviews with several industry editors and writers regarding the importance of Room Acoustics in getting good quality audio in a home theater environment. This first is an interview with Kal Rubinson and discusses, among other things, the first steps in realizing and learning about what it takes to apply correct acoustics to your listening space. For one, it means total commitment to the topic, as room acoustics deals with some very technical measurements, calculations and issues which are not easily mastered. He also addresses a bit of the WAF and how a well-executed acoustical environment can make such a difference, your spouse may be inclined to allow more than you would initially think and allowing both homeowners to become "emotionally committed" to helping the acoustics of a room.

This second one is an interview with John Atkinson who goes over some of ideas of how to place loudspeakers in a room. One of the methods he recommends involves having a friend talk while moving around various parts of the room to see how room interaction affects a normal voice from the source to the listening position. Regarding starting out, he stresses the importance of starting with a good room and then addressing loudspeaker and listening positions (whenever possible).

The third video is an interview with Michael Fremer who speaks about people who may not understand some of the basics such as speaker placement and first reflections. In getting the best sound, it may be that the inherent room construction may play a large part and knowing how to do your best to treat some very elementary problems can go a long way.

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[HookedOnSound]

I watched and listened to the comments and it added a nice dimension to the topic.

From my own experience, room acoustics can have such an impact on the 'finished product'. I have moved my own stereo equip. into a total of 3 homes with the same cable interconnects, receiver, speakers and produce entirely different results. I feel like I am just beginning to understand.

And it's true about fundamentals of audio, you could rely on artificial means (electronics) to correct something, but in the end it's always easier to correct/prevent problems from the start.

Good principles applied properly can save a ton of cash in the long run.

It was nice to watch some ppl to talk about this topic in a conceptual format easy enough for a common Joe like me to understand.

It was also refreshing to hear from experts that you don't have to sink a double-mortgage into a stereo setup to achieve audio nirvana.

We are so bent on getting buying 'pre-packaged' solutions 'cause we are so used to getting instant gratification. I guess we expect a McSound franchise to solve our problems with simply dropping down some cash instead of trying to maximize the most of our current gear with our environment. Room treatment and calibration is definitely not something easy to resell and therefore obviously overlooked.

All I can say is that Information is Power!

As always, Great job!

 

[moverton]

reflective surfaces

I just moved into a new house. The kitchen, livingroom, dining room and family room are really all one room. the house has mostly glass on three of four sides. In addition, there are several stone walls, hardwood floors and a vaulted ceiling.
Needless to say, the echo is pretty bad.
It was a little depressing to hear him say that he basically gave up on his nephew's theatre room.
Anybody have any good suggestions as to how to dampen a space like mine?

 

[sploo]

Hi moverton,

Take a look at my threads on room treatment here:

http://forums.audioholics.com/forums/showthread.php?t=11011

and here:

http://forums.audioholics.com/forums/showthread.php?t=12624

I'd also look into Ethan Winer's articles over at http://www.realtraps.com and his personal website, e.g. http://www.ethanwiner.com/acoustics.html

 

[bpape]

I like the McSound Franchise comment

 

[Ethan Winer]

> It was a little depressing to hear him say that he basically gave up on his nephew's theatre room. <

Just because a magazine writer doesn't know how to solve an acoustics problem does not mean there's no solution!

--Ethan

 

[sploo]

Yes, the McSound thing is funny, and a good point.

I suppose that for a retailer, it's easier (and more lucrative) to sell a high priced receiver/amp/CDP/DVDP to someone that will take it away, plug it in, and convince themselves it's a massive improvement from their previous, probably more than adequate, kit.

Spending the time to explain room acoustics, and the fact that it has to be tailored to the customers' own space, is probably too much faff - you can't really just pack it into a nice 'McSound' box and sell it as an item.

I wonder if there's merit to acoustics companies like RealTraps working with local audio retailers. I.e. having the retailer hand out a flyer to customers, briefly describing room treatment. If they call the office, you then send out a guy with an SPL, laptop, and a set of panels to give a 'no obligation' demo.

I expect you could probably show people how useful the treatment can be (in well under an hour). You'd just have to work out if it's cost effective to have people driving around the country with a van full of panels!

 

[Ethan Winer]

Sploo,

> you then send out a guy with an SPL, laptop, and a set of panels to give a 'no obligation' demo. <

A lot of people believe that's necessary, but it really isn't. Regardless of the room, putting bass traps in the corners and mid/high frequency treatment at the first reflection points is guaranteed to make a huge improvement. If any excess echo or ambience remains, a few more mid/high frequency panels on opposing parallel surfaces will finish the job.

--Ethan

 

[sploo]

Yes, I suppose that's true.

I think the measurement tools are useful, because they can show if you've made a mistake with placement (usually for reflections).

The killer part of measurement is that you can show someone (i.e a potential customer) quite clearly the difference in their room's response - it's hard to argue with a graph full of comb filtering vs. one that's massively smoother. The alternative is back to perception - i.e. does the user 'think' it sounds better.

It will of course, but you're trying to convince people that they need acoustic treament (boring, but useful) instead of a fancy new CDP and exotic cables (exciting, if often ultimately pointless).

 

[Ethan Winer]

Sploo,

> you're trying to convince people that they need acoustic treament (boring, but useful) instead of a fancy new CDP and exotic cables (exciting, if often ultimately pointless). <

Exotic cables are always pointless.

As hard as I work at spreading the word on the importance of room acoustics and treatment, I'd say the ultimate responsibility falls on magazine (and online) editors who are the main influence. Month after month I read reviews of cables, loudspeakers, CD players, power amplifiers - things that, aside from loudspeakers, basically all sound the same. It is very rare to see even a mention of acoustic treatment let alone a review. Even among audio pros things are very gear-centered and the importance of rooms is ignored.

--Ethan

 

[Tom Andry]

Month after month I read reviews of cables, loudspeakers, CD players, power amplifiers - things that, aside from loudspeakers, basically all sound the same. It is very rare to see even a mention of acoustic treatment let alone a review.

While I agree with you, there is a lot more new technology to be reviewed on the electronic side, not all that much new comes out on the room treatment side. How many times can a fiberglass panel be reviewed anyways?

 

[sploo]

While I agree with you, there is a lot more new technology to be reviewed on the electronic side, not all that much new comes out on the room treatment side. How many times can a fiberglass panel be reviewed anyways?

That is a good point - though there will of course be improvements over time in acoustic treatment technology.

The point is that, if you read these magazines (certainly the UK hi-fi mags I've seen), you'd never even be aware that acoustic room treatment existed.

It wasn't until I started reading this forum, because I was disappointed with the sound quality in my room, that I learned of this field (and the huge improvements it can bring, with relatively little cost).

 

[bpape]

And as soon as somebody comes up with some new super-duper fancy treatment that they can charge $1k per square foot for, I'm sure it will get reviewed.

2x4 panels covered in cloth, rigid fiberglass triangles sitting in a corner, etc. just aren't 'sexy.' How many impulse buys do you think would happen if the cover of the magazine was a pile of fiberglass

 

[Ethan Winer]

Bryan,

> some new super-duper fancy treatment that they can charge $1k per square foot for <

You and I really need to do something about this.

I've thought of a series of LEDs that light up showing what frequencies are being absorbed. Or an AC power cord (that does nothing of course) but looks cool. Maybe a silk screened painting on the front surface showing a row of glowing 12AX7 tubes?



--Ethan

 

[sploo]

I've thought of a series of LEDs that light up showing what frequencies are being absorbed. Or an AC power cord (that does nothing of course) but looks cool. Maybe a silk screened painting on the front surface showing a row of glowing 12AX7 tubes?



--Ethan

Make sure the AC cable has been properly burned in. Otherwise it won't allow the panel to absorb properly until it's warmed up .

On a serious note - my mother produces textile based art, and offered (when she has time) to stitch something into the panels, as a stretched linen is pretty similar to some of the canvas work she does.

I've also seen a few pictures screen printed, as you mention, but what was really cool was that they'd printed on the edges. The effect was almost as if the image goes all the way through the object (like the grain in a block of wood or marble).

As long as it didn't adversely affect the acoustic properties, you could offer some form of print service, where the front of the panels get a pattern/image - maybe even an image of the customers choice.

You never know, it might even increase the, ever critical, Wife Acceptance Factor!

 

[bpape]

The benefits of measuring afterward are:

1. Check the impulse response and make sure you didn't miss a reflection somewhere that's within 20ms.

2. Verify the eveness of the decay time in the space. Sometimes your balance may be right but you need to hit another reflection or 2. When you do that, now the absorbtion is skewed too much toward the highs and you may want to limit some of the bass absorbers to just broadband bass by covering them with a facing of some sort to keep things in balance.

Realistically, if you do the analysis of what the space needs BEFORE you treat it, those things will become evident up front and you can plan accordingly.