Needle jumping wildly on analog SPL meter

[supervij]

A friend of mine borrowed my Radio Shack analog SPL meter to level-match his speakers in his brand new setup. He called me to tell me that he's not sure how to adjust the levels cos the needle is bouncing around A LOT. I told him to do his best to "ballpark" it. His living room has lots of reflective surfaces, i.e., walls with pictures and mirrors on it, parquet floors and no carpets or rugs, but there is one big sofa and a couple of leather chairs. I figure his problem might be that there isn't enough absorptive surfaces in his living room. Is that indeed the problem? I also told him that until he gets more absorptive stuff in there, he should rely on his YPAO. Is that generally good advice I gave?

cheers,
supervij

 

[jaxvon]

Is it set on slow?

 

[supervij]

Thanks for the quick response, jaxvon!

I left it on slow when I gave it to him; I assume he didn't change any settings. He's even more of a noobie than I am (which is saying a lot!), so I doubt he fiddled with it. I showed him basic usage, but didn't mention the A or C settings, nor the slow or fast settings. I figure he left it as is, but I'll give him a call tomorrow and find out.

cheers,
supervij

 

[Pyrrho]

Relying on his YPAO is good advice for anyone who isn't really good at setting levels and such. However, he should double check the crossover settings for the speakers and subwoofer, as YPAO often gets those wrong, too often setting the main speakers to large, and too often setting the subwoofer crossover too high (of course, different Yamaha receivers have different versions of YPAO, and some may work better than others). He should also double check speaker distance settings, which he should be able to manage.

As for the needle bouncing around, assuming he is using test tones and not music, the meter must be kept perfectly still, or the needle will bounce around because the sound that enters the microphone will be different aimed in different directions, and he must be perfectly still while reading the meter, or it will bounce around, with many test frequencies. The reason is that sound bounces off of him, and if he moves, he is changing the way the sound is bouncing off of him. He should also have the meter at arms length away (preferably setting on something stable rather than in his hand), and it should be pointed straight up. He should not be directly in the path between any speaker and the meter.

Something like the inexpensive Sound & Vision test disc (retails for about $20) would be beneficial for him to see, which would also help with video adjustments. I highly recommend it; either you or he could buy it, and then loan it to the other one for setting up your systems.

As for his room acoustics, if he hears an echo when he claps his hands, he needs more sound absorbing materials in order to have decent sound. It is a common problem, and correcting it can cost less and make more of an improvement than most upgrades, assuming he does not have total garbage for speakers. It is likely to also make the room look better, if he uses a nice Persian rug and some beautiful paintings on the walls. Even a bookcase full of books will help. Basically, getting rid of that "empty room" echo by putting stuff in the room is beneficial.

 

[supervij]

I just talked with my buddy, and he tells me that he hadn't changed the settings at all. So it had been on C weighting and Slow response time. (He had given the manual a quick read beforehand.)

It seems I have to get back to him again, however, cos you just told me something I didn't know, Pyrrho. I had no idea that I should be holding the meter straight up; I've been holding it with the little microphone pointing towards each of my speakers. And that's what I told my friend to do too. Once I get my meter back, I'll have to level-match all over again, but I doubt I'd have too much variance -- the sound is pretty good to my newbie ears.

I already told him the problems that my 750 has with YPAO. It always sets the centre as large and the crossover at 120. And I did advise him to set everything as small and crossover at 80.

I'll ask him if he hears an echo when he tests for the clap. Er . . . you know what I mean. I suspect he will hear an echo, based on what I remember about his living room setup. His speakers are some 5.1 package he got at Future Shop; I can't remember what brand it is.

Thanks for this help, guys. I like the idea of seeming like an expert to my pal!

cheers,
supervij

 

[Sinsemilla]

I'd recommend telling him to use the Natural setting or whatever the setting in his YPAO on his receiver rolls off high frequencies. If he has a THX receiver, he can use the THX post processing as that too rolls off the high frequencies. Both together might cut out too much, but if his room is that reflective, it might help.

Sort of off the subject, but something I've noticed that I'm sure others who have Yammie receivers w/ YPAO have noticed, is the receiver often sets the distance to the sub further than it is. At first I lowered the distance to how far the sub actually is, but after playing around with it, I found the distance set by the YPAO actually put the sub in phase w/ the rest of the speakers. Of course it will vary for everyone, but it's just something to keep in mind.

 

[supervij]

Hi Sinsemilla. His receiver is the 657, which I don't think is THX certified. Mine is the 750, also not THX. I haven't come across the "Natural" setting in my manual. Where -- and what -- is it?

I noticed the same thing about sub distances the first time I tried YPAO. And same thing, when I changed it manually, it didn't sound quite right. Putting it back to the YPAO suggestion did in fact make it sound better. Funny how YPAO can be so off in regards to some things, but perfect in regards to others.

cheers,
supervij