Axiom Home Page Forums General Discussion Advice from Axiom Owners BFD - Opinions on My Latest Graph Plot

Rick, those peaks in the blue line(I was kidding about whether it was the after result, of course)are about what would be expected from your room dimensions. Both the 20 foot length and width would lead to modes in the high 20s(1130 feet per second/40 feet~28)and the peak in the low 60s area would correspond to about a 9 foot floor to ceiling mode(1130/18)which may be about where the subs are located.

Yes, I certainly interpreted Dennis's curve to be that of his subs alone, but Peter or someone else who was present can clarify that. The reason why I thought yours was also that of the subs alone was that I was interpreting the gentle slope over about 90Hz as being simply the natural rolloff of those subs. I don't follow this "house curve" concept and don't understand why the speakers should be at a lower level.

John,

Man you are spot on with the ceiling to floor heights where the subs are at - due to the slope of the ceiling vault it's about an average of 9 feet as you stated.

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I don't follow this "house curve" concept and don't understand why the speakers should be at a lower level.

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In your opinion would you target a more level line rather than the slope that I have now and throw out the house curve idea?

Since I am in the "know enough to be dangerous catagory" do you think the drastic dropoff at the end could possibly be a phase related issue of the subs with my Axioms?

Thanks for your thoughts and input..
Rick

John and Rick,

The reason Dennis's curve drops off steeply at around 100Hz is that there are no more data points after that. The test disc we used maxed out at 98Hz.

The front L & R channels were active during the sub calibration. This allowed us to adjust the critical range between approx 65 - 95 Hz where the M80s and subs overlap.

Rick, if you calibrate your subs at 85dB, you should do the same with your other speakers.

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Rick, if you calibrate your subs at 85dB, you should do the same with your other speakers.

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Peter,

Since I use DVE to calibrate with isn't it my understanding that the LFE track on that disc is off? Thus the reason for the 75db for the mains and 85db for the sub?

Thanks..
Rick

That has been my experience, but maybe I've just been taken in by the intarweb hype.

We may be having a miscommunication here. When you calibrate all speakers, you should strive to do so at the same dB level. To ensure this is what you're doing, pick a level on your receiver or pre-amp's volume dial that brings the mains close to 85 or 75 dB -- the number you pick is up to you. Once you find that level, don't touch the volume knob until you're done calibrating ALL the speakers.

What this accomplishes is ensuring that your subs and speakers are of similar loudness whether you're playing them softly or loudly.

Since you have a 10dB difference in your sub vs. speaker calibrations, your subs sound (on average) 2.5 times as loud as your speakers. This is bad news from an accuracy perspective.

Not really. There is a (possible, but very likely) bug on the DVE disk where the sub test tone is 10 db lower than the test tone for the other speakers. Therefore, those of us saddled with this disc calibrate the sub 10 db hotter than the rest of the speakers. Sounds good to me!

Ahhhh. I see what you're saying. But that still doesn't explain why the SPL levels are sliding down as the Hz increase.

No, it doesn't, does it... Guess I should actually read the rest of the posts instead of skimming....

Peter,

Kcarlile explains it like I had meant for you to understand about the 10db low LFE test tone on the DVE disc. I thought most everyone knew about that fault in DVE.

Don't tell me I have stumped the experts?...LOL

Now that you have pointed out the drastic drop after the crossover it's got me concerned now as I know it shouldn't drop off like that but stay much higher up. I am loosing db's after the 80hz crossover point and that's not good!!

I think with my Onkyo 601 it will let me turn off my surrounds and center and re-plot with just my mains and the sub or should it be just the sub only?... I have heard that both methods are correct..I am soooo confused now....LOL

Thanks again guys for the continued ideas..
Rick