Axiom Home Page Forums General Discussion Technical Questions Graph testing again, I'm confused, so is mojo :)

I'm going to have to dig out my manual, yeah, can't wait. Those Denon manuals suck.

I think the only way I get the LFE+Main option to appear is if my mains are set to large. This goes against everything all you guys have told me.

Hey boys & girls,

I just tried this again and it is only happening on DIRECT mode. It doesn't happen when in stereo mode (tone controls unby-passed) or any of the surround modes.

So I guess in direct mode, the LFE is sent to the fronts and sub regardless of speaker size settings or cross-over.

But it's still amazing to me that the M80 woofer cones move at 10 Hz!!!!! And why are the mids moving too?

This is pretty funny, I was just typing the same thing. I was going to ask you what mode you are using. I've always used Direct mode. hmmmm

Now I have to rerun my tests sometime. I was even using Direct mode for the RoomEQ Wizard tests in the past. It appears that since Direct and Pure Direct bypass some of the internal circuitry, they must ignore the small/large, crossover, etc...

So if I understand all this correctly, all these years that I've been listening to CD's in direct mode have been ignoring my small and crossover settings?

I thought the purpose of Direct and Pure Direct was to shut down un-needed circuitry, like the video section, to reduce the chance of any crosstalk and give you the best possible performance. What good is it if it ignores your speakers setup settings?

Yeah, same here. I've always been using direct. So I've got all of these freakin' graphs with the wrong mode . Boy, my daughter is gonna be pissed at me because she'll have to re-run all the tests .

Still, I can't believe that the M80s go down to 10Hz. That is just amazing. Granted, you don't hear anything because there is very little air movement from the relatively tiny woofers but I'd bet you can hear them at 20Hz.

What puzzles me even more though is the motion of the mids. That is just wrong! Aren't the mids and the woofers enclosed in separate compartments in the M80s? If not, the mids could be moving sympathetically and that's definitely not good.

I wonder if this is the way it works on other makes. It would help if others chime in here. I wish people would stop spending time with their loved ones and focus on our audio needs .

It would also help if the Denon user's manual was written by someone who had at least a grade 6 English education. I have to read most paragraphs 10 times due to poor sentence structure and even then I wonder if I've understood it right .

Randy, the crossover done by most receivers(including the 2805)rolls off the sub at 24dB/octave above the selected crossover frequency and rolls off the speakers at 12dB/octave below that frequency(this is said to give a good blend in the crossover area). So, as is often mentioned, this is a roll-off, not a very sharp cut-off. The result should be that the M80 cones would still be moving at those low frequency rates of vibration but the extent of the movement should be greatly reduced(i.e. they shouldn't be moving "like crazy"). Have you watched the cone movement with and without the 80Hz crossover to see if there's a visible difference? Another check is to listen in the two situations to determine if the low bass output is in fact reduced with the 80Hz crossover in effect.

Hi John,

I'll have to try what you mentioned. How did you acquire the information about the Denon cross-over? I've been searching for that info for the last few months.

Also, any theory on why the mids are moving at 10Hz? And they're moving "a lot".

I think JohnK just restated what I had tried to mention earlier. But it seems like the culprit was the Direct mode, which defeated settings like the cross over, individual channel volume, etc.

One subtle point about Direct mode is that on some processors this mode will defeat individual channel levels, cross-over settings, digital display, etc for both analog and digital inputs. In other processors, Direct mode will do these only for analog inputs and will maintain more functionality (like cross-over settings) for digital inputs.

John

Mo, I have my sources, but I'm not at liberty to reveal them. Okay, just kidding, of course, or maybe too many hotdogs today. Those attenuation rates are the standard ones determined by THX and others to be appropriate, and are almost universally followed. For example, Sound&Vision includes in their lab tests on receivers the crossover frequency and roll-off numbers measured, and these are nearly always at the specified rates and within a couple Hz of the selected frequency(they test 80Hz, when available). You could look up old Denon tests if you'd like.

As for the movement of the mid-driver cones, this shouldn't happen normally, but at least in Randy's case there again appear to be abnormal influences and spirits in his listening room which are trying to gain control of his M80s(and even a more powerful amplifier may not be sufficient to defeat them). Others might suggest some distortion products of the very low frequency notes, resulting in upper harmonics moving the mid cones, but I prefer the evil spirits hypothesis.