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Testing speakers in room

I recently decided to measure how my speakers work in my room. I'm new at this so I have some questions for more experienced folks. I used the Rives Audio Test CD and the test files for the bass range that I downloaded from RealTraps web site.

1. What's a "good enough" range for home audio? My results are generally within a range of ten decibels (exceptions below). I think this is pretty good, but don't really know.

2. There are two noticeable dips at 245Hz and 2000Hz. The booklet that comes with the Rives Audio CD says that there are often dips after speaker crossover points. The latter dip corresponds exactly to the mid/tweeter crossover of my speakers. The bass/mid crossover is 200; is it reasonable to think that the dip at 245 is also crossover-related? The Rives booklet also says that such crossover-related dips are compensated for by the ears and so are not much of a problem. Is that correct?

3. There is a very noticeable and continuous dropoff above 10Khz. My speakers (Von Schweikert VR IVjr's) are supposedly flat to 20K. Any idea what's going on here? I don't seem to lack treble when listening to music, including things that should generate higher frequencies (violin, some kinds of percussion, etc.). The Rives CD has only three measurements above 10K, which may not be a fair test. (Any better CDs available?)

4. I have one other peak, in the bass centering on 184 Hz. The readings are generally between 75 and 85 dB, but this peak goes up to 93. How do I treat a problem like this? (Or do I?)

5. I decided to take measurements because I get muddy bass on some recordings, particularly orchestral works. Based on these measurements, there do not seem to be serious room/speaker problems (except possibly that one peak). What else might be causing my bass issues? I am thinking about resonances with the wooden floor in my house. Right now the speakers are on the factory-supplied spikes, resting on the supplied disks.

Thanks and Happy Holidays!
magister
rlwainwright
1,904 posts
 
Most of your issues could be fixed using an equalizer, give that a try. And 10db is a big peak (or trough). You'd probably like the system's sound better if you could get those leveled out to no more than 4-6db.

Merry Christmas!

-RW-
acoustat6
357 posts
 
Hi Magister, The way you are measuring is not a high enough resolution and it is only part of the story. You also need to see waterfall plots and RT60 times.

The best way to do this is with the FREE program REW (Room EQ Wizard) available for FREE at the Home Theater Shack. ITS FREE!!!!!

1) plus or minus 5db is good, plus or minus 3bd is exceptional, You can always plan on a few large peaks/nulls that are part of your house sound (along with the sound of your equipment)

2) you "can't" do anything about the sound of your equipment, so buy quality. You did:). Your ears do have the ability to compensate depending on the Q and levels of the peaks and nulls. But dont expect them to compensate for a 10db peak/null.

3) Radio Shack meter is not accurate at these frequencies.

4) The difference between 75 and 80 db is twice as loud! 93db is definitely giving you bass boom.

5) It's all frequency-related. Base peaks limit the volume you can listen at. They also affect the sound of recordings where some may appear skewed.

The answer to your question is bass traps and broadband absorbtion of enough size and quantity to effect a change in room.
Bob
magister OP
22 posts
 
Thanks, guys. I will check out the REW program and persevere in my efforts to improve the sound!
acoustat6
357 posts
 
Hello,I wrote, "4) The difference between 75 and 80 db is twice as loud!"

Actually it is the difference from 75db to 85db.

Bob
dan_ed
2,451 posts
 
Don't forget, you are really measuring room response to your speakers. The published specs for speakers are done under anechoic conditions. I'll second Acousta6's recommendation for RoomEQ Wizard. It takes a little while to figure out how to use it, but nothing really that complicated. And, best of all, it works and is very helpful with tuning the room.
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