Best use of Computer based measurement systems to solve Bass Problems

0 Members and 1 Guest are viewing this topic. Read 6312 times.

*Scotty*

It would be very helpful if those who have used advanced measurement techniques to solve bass problems, such as computer programs utilizing calibrated microphones and the like, would post their experiences.
For instance what programs you used and what approaches proved to be the most effective in defining the scope of the problem.
It would also be nice to know what methods you used to solve your bass response problems once you had them identified.
Scotty

medium jim

Scotty:

Great question!   It would be great if those in the know would chime in with some answers as it would benefit all of those (like me) who are clueless in this area.

Jim

JohnR

The article by Nyal Mellor and Jeff Hedback would be worth a read. It's not exclusively about bass.

http://blog.acousticfrontiers.com/whats-new/2011/10/13/acoustic-measurement-standards-for-stereo-listening-rooms-pu.html

I guess I'm not really sure what *Scotty* wants to know. Using a mic and REW or some other measurement program is a faster and more accurate way to measure in-room response than RTAs or test tones, and will also measure some things that you can't with those other tools (see article above for some examples.)

I started by moving a subwoofer into every reasonable location and measuring the response. That also confirmed that my room behaved more-or-less as the modal simulator predicts. I then tried pairs of subwoofer, as per suggestions by Toole (I think). Sometimes response or decay was better, but it was hard to get them positioned just right. Then I tried dipoles in various locations and orientations. From all of that, I decided what was best for me, set it up that way, and thought about the best steps to take next (still in development).


bpape

  • Industry Participant
  • Posts: 4450
  • I am serious and don't call my Shirley
    • Sensible Sound Solutions
I would agree with REW.  Great tool that gives a lot of good information and is pretty easy to use (and free!). 

An RTA (which REW also has) can be useful for placing subs easily by leaving it on with the mic at the seating position and moving the sub around while watching.  This allows you so put the sub on something that makes it pretty easy to slide and make very small adjustments continuous adjustments instead of placing the sub in 100 different places and taking 100 different measurements.  When you get close, then you can look at the static measurements to help blend the sub with the mains.

Bryan

*Scotty*

What microphone should be purchased to use with REW?
Scotty

medium jim


JohnR

What microphone should be purchased to use with REW?
Scotty

I think this is a good choice. I'm just wrapping up a review of one now.

 http://www.cross-spectrum.com/measurement/calibrated_dayton.html



*Scotty*

Thanks to all for the software and microphone recommendations. This is some of the information I was hoping to see.
It looks like the cost to get started measuring your room and your speakers is about equal to the cost associated with the Dayton microphone options, $75 for Basic Plus or $99 for the Premium Plus microphone.
 There appears to be very little to stop the average audiophile, except a lack of interest, from measuring the interactions between their system and their listening room and making informed decisions about what steps to take towards optimizing the relationship.
 I like Bryan's recommendation,  leave the RTA on and move the sub around until you find the best location. In my case I will be moving the second sub on the wall at the rear of the room to find the spot where the bass measures the flattest.
Scotty

JohnR

*Scotty*, you also need to add the cost of an audio interface.

I'm not seeing how the method proposed by Bryan can be very effective. It won't be any faster, as you have to move between the sub and the laptop anyway, so you may as well press two buttons each time to get a measurement. Once you've moved it a few times, you won't be able to remember if this RTA is better or not than which other. And then, when you want to optimise decay times, you'll have to move the sub all over again and measure anyway. I'd suggest a methodical approach, mark a set of locations on your room diagram, move the subs there and measure. Then label them in REW for future reference. Then you can analyze them and decide on the next move(s).

*Scotty*

John, Is the audio interface you are referring to a mic preamp or some other kind of box separate from the computer and the Mic
Silly me. I thought the mic would just plug into the microphone input on my laptop.
Never mind, found phantom powered XLR USB interfaces from $29 to $100. It looks $100 to $150, with a worst case of $200 total to get started on measuring.
Scotty.
« Last Edit: 24 Sep 2012, 03:12 am by *Scotty* »

JohnR

Check carefully on the cheap ones before purchase, some of them don't work...

*Scotty*

I have my eye on a Tascam 122Mkii.
Scotty

JohnR

I was going to say I don't know why those seem to be popular, but I've realized that you can get them for less than half theprice I can:

http://www.bhphotovideo.com/c/product/657978-REG/Tascam_US_122MKII_US_122MKII_USB_2_0.html

http://www.amazon.com/Tascam-US122MKII-Audio-Midi-Interface/dp/B002TTOJUC

I haven't checked or measured it but a friend of mine is using it successfully with REW. You have to remember to turn the monitor contorl knob the right way.

medium jim

Sounds like I need to break down and get in the 21st century and see if my ears are as good as scientific measurements.  Nothing gained by sitting on your keester!

Jim

JohnR

Sounds like I need to break down and get in the 21st century and see if my ears are as good as scientific measurements.  Nothing gained by sitting on your keester!

No, not much. Although I think you're setting yourself up with the "measurements vs listening" angle. It's not a challenge, it's about (IMO) using the tools that you have (or can have) available to you to make your listening experience better.

At this point, it looks like the "cost of entry" for those in the US anyway is $70 for the calibrated mic and $80 for the interface, plus some postage charges. So $150+ total. Ask in the Path of Least Resistance for a "budget" interconnect or power cord and see how many answers you get below that figure. Just putting it into perspective...

jtwrace

Sounds like I need to break down and get in the 21st century and see if my ears are as good as scientific measurements. 

Jim
I'll put money on it that they aren't.

kevin360

  • Full Member
  • Posts: 718
  • án sǫngr ek svelta
Thanks guys! For better or worse, I just committed myself to enter the measured arena. I ordered the Cross-Spectrum Calibrated Dayton mic and the Tascam 122MKII mic pre. I guess it's time to familiarize myself with REW.

To be honest, I've been keen to measure for some time, but I am also aware that ignorance can be bliss. As it stands, I'm rather happy with things, but I also understand the degree to which our brains compensate - especially when it's all as familiar as we each find our own setups (which can work against neutrality in rating the sound of 'foreign' systems). Still, it will be very interesting to see how the ''feeling around in the dark'/'just plop the subs over there'' method measures. I've moved my Magnepan 3.7s around quite a bit, but I've only tried my subs in a few absolute (no micro-nudging) locations. The addition of room treatments has been done in a formulaic manner, but some of that isn't mobile (front wall diffusion is glued in place and the corner traps are designed for that specific location).

Thanks for the recommendations, but I fear that this genie is going to be tough to put back in its bottle. I confess a few OCD tendencies and tools like this definitely feed that monster. :lol:

medium jim

I'll put money on it that they aren't.

Thanks for you vote of confidence...

I agree with John, it's about the knowledge of it and using it to ones best advantage!

Jim

medium jim

Thanks guys! For better or worse, I just committed myself to enter the measured arena. I ordered the Cross-Spectrum Calibrated Dayton mic and the Tascam 122MKII mic pre. I guess it's time to familiarize myself with REW.

To be honest, I've been keen to measure for some time, but I am also aware that ignorance can be bliss. As it stands, I'm rather happy with things, but I also understand the degree to which our brains compensate - especially when it's all as familiar as we each find our own setups (which can work against neutrality in rating the sound of 'foreign' systems). Still, it will be very interesting to see how the ''feeling around in the dark'/'just plop the subs over there'' method measures. I've moved my Magnepan 3.7s around quite a bit, but I've only tried my subs in a few absolute (no micro-nudging) locations. The addition of room treatments has been done in a formulaic manner, but some of that isn't mobile (front wall diffusion is glued in place and the corner traps are designed for that specific location).

Thanks for the recommendations, but I fear that this genie is going to be tough to put back in its bottle. I confess a few OCD tendencies and tools like this definitely feed that monster. :lol:

+1

Jim