Axiom Home Page Forums General Discussion Home Theater Question about ypao and vx2700

All - I have the vx2700, M60's, EP500, a VP150 & 2 QS8's. I just moved back into my old house and have a pretty ideal setup in the basement for HT. The room is proportional with walls on 3 sides & behind me open. My old apartment was a square room and I ran YPAO again after getting setup. I feel it's been with mixed results:

Distance measurement turned out pretty accurate:
Front L&R 11ft, Center 10.5ft, Surr L 7ft, Surround R 8ft (this wall is slightly recessed where the speaker is mounted), Sub 1ft (the sub is in the front left corner of the room - to the left of the front L speaker)

Speaker Level was interesting:
Front L +9.0dB, Front R +9.5dB, Center +6.5dB, Surround L +7.5dB, Surround R +7.0dB, Sub -9.5dB. It set the fronts to Large, everything else to small and the bass cross over to 100Hz.

I'm not really sure why it would find the right surround to be further away and then make it quieter. However my biggest concern is optimizing the sub. Is 100hz the correct mix for this speaker/sub combo? Should it really be turned down that far?

I was testing after setup with 'I Am Legend' on blu-ray because when I watched it a couple of weeks ago, the audio blew me away. More specifically the scene where he's loading the wife and kid on to the helicopter. Before I swear it felt like the helicopter was in the room. Now, not so much.

Random questions:

What are the 'suggested' settings for the EP500 & 60's. What should the crossover be set to? What about the bass volume? Right now I have it at about 9pm on the dial and have crossover set to "bypass". Anyone have any suggestions in regards to the vx2700?

I realize it's very dependent on the room acoustics...and the room is largely empty at the moment.

As I wrote up this post, I did some more testing and spread the speakers further and moved the sub in between the Front L speaker and TV. Here are the new recommendations:

Distance:
Front L&R 11ft, Center 10ft, Surround L 7ft, Surround R 8ft, Sub 1ft (the sub is now between the Front L and TV)

Levels:
Front L +8.5dB, Front R +8.0dB, Center +4.5dB, Surround R&L +6.0dB, Sub -8.5dB. Still reading the fronts as large and the rest as small.

Before the 60's were about 7 foot apart (inside edge to inside edge), now they're about 11 feet. Any input would be welcome.

Try this post by Mojo about halfway down the page and see what the results are.

Link

blair,

I have the 80's + the 600, and for me, my preferred XO setting is either 60 or 80hz. This is with the fronts set to small and the subwoofer set to "Main + LFE" in the Denon's configuration menu.

Also, unless you have your gain knob turned up pretty high, -9.5 dB sounds low to me, but obviously that's entirely based on where your sub gain knob is. Do you have an SPL meter by chance? That's the best way to level match everything and it's a fairly modest investment once you've put the money down for a quality system like you have.

I remember the helicopter scene well... it definitely should shake the room with the setup you have.

Jason

I must have something mis configured. Or the room isn't playing nice. As you mentioned, in my apartment (the mostly square box) the bass thumped in those scenes. It's the first time I can remember watching something and going "wow, that's the 'feel' of that particular sound in real life". It just seems hollow now. I guess I'll finally get a SPL meter. Questions:

1. Radio Shack still the easiest place to get one of these? Electronic fine? I know there was the whole thing about the analog version...
2. Is there a guide floating here to understand how to use one (I'm willing to learn, but don't know much at the moment).

-Nick

Actually, if it's really as easy as this article makes it sound, it should be pretty straight forward.

http://www.techlore.com/article/10037/

I'll tinker with the crossover. I remember know why I was using 80hZ before (and the other settings): phase - 0, Volume - 9 o'clock on the dial, crossover - 80, trim flat. It's suggested by the EP500 Instruction manual.

I'll get a meter tomorrow and play around with it.

-Nick

Nick, although YPAO's setting of the M60s large is "correct" from the standpoint of their low bass capability, I'd nevertheless suggest that you set YPAO to skip that setting and manually set all speakers small, with the sub setting LFE. Give the EP500 more of the bass to handle that it does best and less to the M60s so that they can play the higher frequencies a bit more cleanly.

If you get the RadioShack SPL meter, I'd definitely suggest the digital rather than the analog model, as it has more comprehensive measuring modes(e.g., a "Max" level measurement).

Nick,

Another huge factor that could be affecting you (and maybe the simplest to fix) is positioning of the subwoofer. Have you done the subwoofer crawl in your room to find the best placement for the subwoofer?

I just learned about this myself during my system setup and was amazed at how much placement can affect your perception of bass in your main listening position. You can do this without the SPL meter just by listening, but having a meter will help as well. Put the sub in your main listening position and then crawl / walk around the room with the SPL and see where you are getting the highest SPLs when running the test "warble" tone from your receiver.

That's a brief summary of the two articles I linked to above. If you haven't done those tests, you might fix your problem by experimenting with placement.

Jason

That's awesome about setting the sub where you're sitting and work backwards to find the correlating spot. It's also perfect right now as I don't have any furniture in the viewing seat till the couch gets delivered.

I was thinking more about this last night, and it makes sense that things don't sound as "pressurized" I guess. Before I was in a box, now it's a long room and I'm probably not getting the effect of all that volume in a small space. Not that I know anything about acoustics I guess. Either way I'm sure it'll improve once I've done some of these tips. Off to pick up an SPL meter now.

-Nick

Cool, happy shopping. As an FYI, I'm guessing you'll find that playing with placement should help considerably.

In theory, a rectangular room is better than a square room for even bass response. Square rooms typically have more problems with peaks and nulls in response throughout the room. If you were sitting in a big peak position in your last room, that might explain the differences you are experiencing now if you are sitting in a flat or null response area.

Ideally, find a position that produces the smoothest response in your primary listening position. The SPL meter should help you with that considerably. If you want more help flattening response, take a look at the free REW software to give you an idea how good/bad your response curve is in your primary listening position for different sub placement options. If you end up wanting to go to this level of detail, you'll need some more parts when you go shopping (mainly mini stereo plug to dual RCA converters to connect the SPL meter to your computer, pictured below).

Okay, so here's what I did.

1. got the meter, went home.
2. drove back to the store for a battery.
3. Downloaded test wav files here here
4. Since the files are mono I kept switching the inputs for my different speakers into the Front L ports. Hopefully this was right.
5. Got new readings:

Front L & R +8dB, Center +3dB, Surround L +8dB, Surround R +7.5dB, Sub -2.5dB. The one that stands out as different is the sub which is much higher.

I haven't messed around with moving the sub about yet. Unfortunately work is beckoning so I'll have to turn to that for a few hours and revisit this later

-Nick