Room measurements and Audio Interface equipment

[F u r u y á]

Hello !

 

My first post here.

 

I want to get all the equipment needed to take some room measurements (and then later on treat it).

 

So I was following this tutorial, in which there's the following diagram:

 

 

Equipment needed

 

 

 

 

So I spent the last hours searching for an audio interface. And I was almost buying a $200.00 one when I realized that I already have a DAC (I'm dumb )! My system is: PC -> DAC -> Amp -> Speaker.

 

So (I guess) I need just a Mic Preamp with digital output (Mic Preamp + ADC). I was wondering if such equipment exists.

 

If such equipment does not exist, then the benefits (I guess) of the aforementioned Audio Interface is that it's DAC + Preamp, allowing me to connect more speakers (more specifically subs, for a distributed bass system) at line level.

 

 

Well, back to the topic, I just want to take room measurements for now. If such equipment does exist for affordable price (less than $100.00) I'd go for it, otherwise I'd be better off just getting an audio interface, right? What are your thoughts?

 

 

Regards,

 

F u r u y á

[LBob]

It does exist. If you go to the Dirac site you will see some that are for sale. I think the price is around 150 uSD though. Good luck.

[F u r u y á]

Only found this one (suite):

XTZ Microphone to Dirac Live Room Correction Suite™ - XTZ Hifi

$ 330.00

 

And this one (suite):

XTZ Room analyzer II Pro - XTZ,Swedish Design, Dirac Live Room Correction Suite

$ 360.00

 

 

I'm about to get this one (audio interface):

Amazon.com: Tascam US-144MKII USB Audio Interface: Musical Instruments

$ 96.00 (24/96 with phantom power)

 

Or this one (audio interface):

http://www.amazon.com/dp/B005OZE9SA/

$ 150.00 (24/96 with phantom power + lots of reviews )

[F u r u y á]

Bought this one: Focusrite Scarlett 2i2. Mostly because of the popularity (seems to be a traditional brand).

[iago]

I was going to suggest Focusrite, but it seems you already found them. Hardware is OK for the price point (actually the analog section is better than the digital one) and sufficient for simple measurements.

 

Drivers are obviously a weak point; to be able to use 24 bit sample size you have to use ASIO drivers: is my interface in 16 bit or 24 bit on windows. Don't bother with the CD, always use the latest drivers.

[F u r u y á]

I will. Thanks for the informations!

[mayhem13]

What's going to be of greatest importance here is the software and how intuitive it is and the users understanding of gating. What happens below 800hz IMO is the most problematic range in most rooms as that's where all the 'mud' happens. It's also these lower octaves that are most difficult to accurately capture. Good luck in your measurements. The results will be very telling I'm sure.

[F u r u y á]

Thank you!

 

All these information (that seem to be trivial to you) are completely new to me, and I appreciate it very much. It will for sure help me when I start this project.

[crisnee]

Some people in the know suggest not messing with frequencies above 300 hz. I'm not one of them, but I agree that the biggest problems occur in the low frequencies.

 

Chris

[F u r u y á]

Oddly enough, those problems are encouraging me to start this project

 

 

When you say that a certain frequency is problematic, are you saying that it is problematic to measure, to treat, or both?

[InfernoSTi]

For me, in a small room (all our rooms are basically "small" compared to concert halls, etc) thinking of the room above and below 500 Hz is key.

 

Below 500 Hz, my concern is bass modes where you get dramatic spikes and valleys due to standing waves. Treatment is easy enough to "tame" in my opinion.

 

Above 500 Hz, there are two issues that make things interesting. First reflections (not easy to measure) and overly long decay (as seen on waterfall charts) can cause major clarity problems first reflections should be treated, particularly on the side walls (and back wall if you are very close to it, say less than ten feet). I think absorption is a good place to start for both first reflections and decay issues.

 

Yet an overly absorbed room can sound "dead" so I like to mix absorption with diffusion to keep a "live" sound but address first reflections and decay issue. When combined with bass traps, you can address the whole range without creating problems from the treatments themselves.

 

Best,

John

[F u r u y á]

Nice, thanks for the information!

 

Good that you mentioned small room (important information that I skipped); mine are very small:

 

Room 1

3.7 x 2.4 x 2.5 (m)

12 x 7.8 x 8.3 (ft)

 

Room 2

3.1 x 2.4 x 2.5 (m)

10 x 7.9 x 8.3 (ft)

[InfernoSTi]

You may want to read this recent thread: it might be a helpful discussion!

 

http://www.computeraudiophile.com/f23-dsp-room-correction-and-multi-channel-audio/basic-room-correction-20430/

 

And you may want to read this article:

 

http://www.decware.com/paper14.htm

 

Here is another article that is very interesting to read with regard to the issue of first reflections:

 

http://www.gedlee.com/downloads/Philosophy.pdf

 

In short, your rooms will have some challenges that I believe will need absorption on the side walls (at the first reflection point) and back wall (directly behind the listening position) and bass trapping in the corners. It may also benefit from Dirac in the under 500 Hz zone.

 

Speaker placement will be key. You might want try out the non-traditional orientation method (axis not at 90 degrees to the front wall but say 30-60 degrees). At least do the "turn your speakers 180 degrees" (i.e. face the speaker exactly opposite facing you) test: that will give you a good idea of what the reflected sound level is (100% of what you hear will be reflected). This may amaze you as we "perceive" we are hearing mostly directly but in reality there is a lot of reflected sound. The test lets you "believe" what you read easier (hearing is believing).

 

John

[Bilderspiele]

I use my room sideways. The room size is 4,25 x 5,20 x 2,55 m.

I have 1 m distance from the left wall to the left speaker and 1 m distance from the right wall to the right speaker. Same for my surround speakers. I use heavy room treatment for the acoustics. Bassabsorber at the front and rear walls. Midtoneabsorber at the ceiling. It's very quiet now in this room. For low frequency speaker I use a dual bass array. This give bass response of +- 1 dB from 16 Hz to 80 Hz. It's powered by 2 x 800 Watts.

[F u r u y á]

It may also benefit from Dirac in the under 500 Hz zone.

 

Speaker placement will be key. You might want try out the non-traditional orientation method (axis not at 90 degrees to the front wall but say 30-60 degrees).

Are you talking about this software? Interesting. But won't it make the sound better only at precisely the listening position? (just wondering the effectiveness of it against room treatment, please pardon my ignorance!)

 

 

Speaker placement will be key. You might want try out the non-traditional orientation method (axis not at 90 degrees to the front wall but say 30-60 degrees).

My speakers are toed in since I got my first (and current!) system; 60° from the wall (equilateral triangle with speakers and listener being the vertices). I actually have no evidence that this is a good setup for my room (it was just written in many tutorials and also in the speaker manual), which is by the way one of the reasons of why I want take measurements and (hopefully) conclude which setup is ideal for me.

 

~

 

Thanks for pointing out valuable resources! I will read them as soon as possible.

[F u r u y á]

I use my room sideways. The room size is 4,25 x 5,20 x 2,55 m.

I have 1 m distance from the left wall to the left speaker and 1 m distance from the right wall to the right speaker. Same for my surround speakers. I use heavy room treatment for the acoustics. Bassabsorber at the front and rear walls. Midtoneabsorber at the ceiling. It's very quiet now in this room. For low frequency speaker I use a dual bass array. This give bass response of +- 1 dB from 16 Hz to 80 Hz. It's powered by 2 x 800 Watts.

That's plenty of power to your room! oO

 

Nice. My goal is to install a distributed bass system too, in the future (near, hopefully!). I just have to read about it first (and decide whether or not it'll be a good fit for me). And read about room treatment too. And take the measurements (learn how to use the measurement software first). And more.

 

That's a lot of things, but I'm excited to go through each one! And I hope I can get some help here at Computer Audiophile

[dean70]

This site hunecke.de | Room Eigenmodes Calculator contains some useful calculators for room acoustic behavior.

[F u r u y á]

Very nice! Much appreciated.