Help with understanding Stereophile test results.


Hey all,
I ran the Sterophile test tones and just wanted to know if anyone can explain any potential issues based on my numbers, they are as follows:
R L
1K 80 81
200H 68 80
160H 67 78
125H 74 79
100H 74 79
80H 70 74
63H 68 70
50H 67 70
40H 76 73
31.5H 75 76
25H 72 75
20H 65 67
Thanks for any help or insight you can give, Cheers
chadnliz
If you used a Radio Shack meter, you need to correct the meter with a compensation chart. I have values obtained with top-dollar pro audio test equipment embedded in an Excel spreadsheet - if you want me to email it to you, let me know and all you'll have to do is plug your readings in.

With the correction in mind, your response looks pretty good. Your (mid)bass may be a bit weak but it could be my tastes talking more than anything. What do you think about the tonal balance of your sound?

Arthur
Rives Audio CD has a series of test tones compensated for the (formerly) Radio Shack meter.
I never thought anything was really bad or lacking so I just ran the test to see what it says, after talking to a dealer friend it would appear I am not that bad off but I suppose I need to check these against a compensation value for the digital Ratshak meter I used. Any reason for the weak midbass?, and if so what should the values be..in the low to mid 70's? Thanks for any additional help.
This is a speculation, but I am wondering if the midrange drivers on your speakers are starting to roll off in the mid bass, which is where many speakers roll off...then the woofers kick in. It could be a less than perfect crossover integration between the mid and bass drivers.
Those aren't bad numbers. The broad bass dip is not all that substantial and better than any sharp peaks. Room treatment is difficult to nearly impossible in that range but it wouldn't hurt ... too much.

If that 10 dB is really that noticeable, perhaps the best cure would be a Rives PARC or one of the digital equalizers.

Well chosen but modest system. Flat would be optomistic and unrealistic.
1. Those are not bad numbers.
2. You need to measure more, both in terms of frequency spacing and multiple readings. In-room frequency variations are generally sharper than can be distinguished with certainty from one measurement at only one place.
3. Room treatment down to 100-125Hz is readily doable. Below that, it becomes fairly bulky and inconvenient but still doable.
thanks guys for all thoughts, I never heard anything bad but I ran the test to learn more so just trying to make sense of it all....................much appreciated.
I hate to intrude on the question of this thread, but can anyone explain what the "compensation chart" is and what is the need/purpose of it for testing the frequency response. Maybe I should post this such questions as a new thread, but since I own a Radio Shack SPL meter (digital), I never really understood what people mean when they say it needs to be re-calibrated. I mean, isn't it just measuring sound pressure? Thanks to anyone who responds.
Chad -- what are you measuring FOR? If it's balance b/ween the spkrs, then you have an IMbalance in the mid-bass and lower between L-R. This is probably due to spkr positioning/room interaction.

I never really understood what people mean when they say it needs to be re-calibrated.
If you measure sound pressure against a "reference" -- say 1kHz -- you want the measuring device to equally sensitive at all other frequencies. If it's not, then you'll get a lower/higher reading at some frequencies even the the actual sound pressure level may be the same.... it;s just that the meter isn't reading correctly.
So, for the ratshack you get a chart which shows you how far off from reality the meter is at each frequency -- and you compensate to get the real -life reading.