Official Rythmik Audio Subwoofer thread - Page 202

Sofast1,
If you really don't want to spend that much for a SPL meter or before you do read this link:
http://www.avsforum.com/avs-vb/showt...ion+microphone
After reading this I have been using my RS meter for level cals and the Audissey mic for calibrations. There's really no way to know if my mic is as accurate as the one on the link and I'm not sure it really matters all that much. I already had the RS meter and the same Audissey mic and couldn't justify the price for the Galaxy. My Audissey mic did read different from the RS meter with the generic calibration file all I can say is it sounds good to me.
Larry

I'm totally confused. That shootout said the R/S meter was very accurate 7-200hz,yet that's the range the correction tables and the reviews of the R/S meter say is the most inaccurate. To make things worse,Rat Shack has a new model on their web site(the old one is gone,can't compare) which none of the stores have. It looks completely different and no one at R/S knows the difference between the new and the old model(which they still have in the stores). Price is the same. Who knows if the new model will need correction tables and/or if it will be the same table as the old model. Radio Shack has just about frustrated me into buying the CM-140. I had decided that the R/S meter would be good enough for balancing channels and I could check the response of the subs with the correction table(how many times would I do that anyway?). After that, It would probably sit in a drawer. But.......R/S has got me so pissed off;I'd hate to buy the old one and then find out the new one is better,or the opposite. No one at R/s can tell me the difference,at one of the stores I called,they couldn't even find one(new or old)! So,the CM-140 is $70 more and I really don't need it,but...................someone help me.

For casual use anything is workable. If you care then you have to spend more. By the way a characterized ("calibrated") mic + REW is not an SPL meter until you calibrate the REW system. Mic calibrators are not the cheapest gadget you can buy but not the most expensive either.

A calibrated measuring system is one of the pleasant side-effects of having Audyssey.

I'm not really interested in Audyssey or REW,nothing against either. The CM-140 is calibrated. I know it's more than I need,but so are 2 F15HPs! I'm leaning that way now. How about your opinion-is this http://www.cross-spectrum.com/measur...ted_cm140.html worth $70 more than the R/S meter?

"Calibrated" does not mean it is accurate in the sub range. A calibrated CM-140 that is tracable to NIST is still calibrated only down to the C weighting low end, around 30 Hz. Unless they are doing a full-range calibration? The compensation tables for the RS meter compensate the LF roll-off. The RS is not a terribly accurate meter, the compensation required is pretty large at LF, and meter variability pretty high. Good enough for a decent relative reading, but don't expect 1 dB numbers. NIST calibration runs $100 - $300 for most SPL meters. I have not looked recently, but full-range meters I have seen in the past were in the $500 range and up with a cert.

All that said, with compensation tables my $50 RS meter measures very closely (within perhaps 2 - 3 dB) to my $600 Earthworks measurement mic down to 20 Hz or so.

Thank you for your input.The details of the calibration(done by Cross -Spectrum) are in the link above in post #6034. As I mentioned previously,your R/S meter is discontinued and the new one is completely different(see their website). No one knows if the new one is better or worse,or if it needs a correction table and/or if it would be the same table as the old one. Too much confusion, I spent an extra $66 and bought the calibrated CM-140. I know the R/S meter probably would do everything I need,but seeing as how I just put 2 F15HPs in a 2600 cu. ft. room,it seems to be overkill week!

This was interesting too;http://www.soundandvisionmag.com/art...r-good-measure

Thanks! I just bought one and he's shipping it tomorrow!

Yesterday I wanted to do kind of an "articulation" test,so I decided to spin some vinyl. In one word;amazing! Today I downloaded the RealTraps test cd in anticipation of my new spl meter and just for the hell of it put it in the cd player. Volume was at-32db as I didn't want to do any damage. Played track one(10-19hz),not knowing if I'd even hear anything. Holy Crap! Not only could I hear it clearly,it rattled windows in the kitchen!! These subs keep impressing me:

Glad to help. Sorry I miss the discussion leading up to your purchase. My lady friend came over and we grilled out and watched a movie. Lucky for me she likes music and movies as much as I do so is very tolerant of my shall we say obsession. I wouldn't have added much anyway. I would also suggest reading Paul Spencer's bass integration guide I found it very interesting. Just look for him on here I'm at work and on my phone again so it's not easy to add a link.

So with Sofast1 talking about doing the phase adjustment and using Brian's calculator and it being good, I experimented a bit today with all this. My new RS SPL meter is still at work, so I can't take measurements yet, but I did a listening test and I'm noticing something interesting and unexpected. I was hoping you guys could see if this makes sense to you.

My Pioneer receiver after running MCACC set my sub distance to 9' 8.5"
Brian's calculator tells me to set them at 6' 8.5"

Here's my interesting results: I actually notice more bass with the default MCACC setting, but I notice tighter, more articulate bass at Brian's setting.

I used to DJ so I have a pretty good sense of timing and beats and can tell when two beats aren't aligned. It's almost like with the MCACC setting, the beat from the subs was slightly delayed sounding and therefore the overall sound was more muddy.

But with Brian's calculator setting, there is no separation of beat between sub and mains and therefore it sounds extra tight. The sub hits at the exact same time as the mains do. I never even realized it was off before hearing this. But strangely the overall output seems lower. I'm not noticing the subs as much as I am when it is set the way Pioneer is recommending it.

But since it is a cleaner sound, I think I'll keep it.

Anyone else find this interesting? What is the effect I am noticing? And why do you guys think it has an adverse affect on perceived SPL? As I understand phase alignment it should increase SPL. Of course I haven't actually measured this yet, so it could be all perception.

Brian's calculator? Sounds like it would be valuable to try!

Is anyone using the filtered line out from the A370PEQ?
I'm planning on going dac/preamp > sub > amp, but only if the high passed signal is 100% transparent. Does it add gain? Or any audible effects?
Thanks for your help

That is interesting results. I am planning on using the calculator as well, but need to run YAPO first (still pretty new setup and not done with construction quite yet either) to see what the difference are.

I'm wondering if your perception is that it is louder because it is slightly more pronounce since the timing is off where with Brian's setting it is hitting when it should so it doesn't stand out as much. That would be my unprofessional non audiophile's take on what might be going on.

Looking forward to "hearing" your impression after you can take some measurements.

Regards,

RTROSE

Just wanted to thank you for mentioning the RealTraps test CD. I downloaded it and gave it a whirl. I was also shocked I could hear the test tones as well even the 10hz section. I was not playing anywhere near reference levels (too many people home), but was pleasantly surprised none the less.

Glad to hear your enjoying your new "babies".

Regards,

RTROSE

That was what I was thinking and why I was sure to use the word perception there. Cause I'm not sure if it's real SPL I'm hearing. Might just be more bass spaced out over a longer time. Within the next two weeks or so I'll run some test tones near my crossover and see if there is any actual SPL difference when you isolate it to a single tone and aren't hearing it in a song.

http://www.rythmikaudio.com/subtuner2.html

three things;
you must have java to open it
you must specify which input on the sub you're using(LFE or line in),as it will effect the result
changing the xover freq will change the result

I had one of these......was not impressed honestly, returned it within the week........so I use 2 items now only. 1. An audiocontrol 3055 RTA with a pink noise disc(still the best calibrating tool thats fast an easy to use). But most people don't want to spend this kind of money(even though its highly worth it. And 2. Dayton's Omnimic: http://www.parts-express.com/pe/show...ource=googleps

If you want something simple and easy to use and relatively accurate, the Omnimic is the best bet. Dont need to go hunting around for seperate mics, sound cards etc......... For $300 or less its the best.

Not disputing anything you said,but your'e talking about almost $2000 worth of equipment that requires a laptop and I'm talking about a $129 hand held spl meter(and I don't have a laptop). The CM-140 is calibrated to 1 db and I believe it will do everything I need it to(not that much). Plus, I can spend the $1830(plus laptop!) I saved on audio gear!

I'm the wrong person to ask. I have the original analog RS, the "digital" version, a characterized 140 and a characterized mic.

I use REW since I want to use swept sine and I'm too lazy to add the compensations by hand.

My C characterization file goes from ~ 4Hz to 25KHz.

FYI Cross-Spectrum does not calibrate these devices. They're characterized. If you need () calibration I believe they can refer you to an appropriate facility.

That opionion is not universally shared.

You don't need a laptop. I use my desktop. It is in the same room and I have some really long cables to connect it to my AVR.

If you want something simple and easy to use and relatively accurate, the Omnimic is the best bet. Dont need to go hunting around for seperate mics, sound cards etc......... For $300 or less its the best.[/quote]

And you still need a SPL meter to set your sound level.

With the omnimic you do not need a separate SPL meter. It has an SPL meter function.

http://www.daytonaudio.com/OmniMicV2/hs20.htm

-Mike

From the Cross-spectrum website;

Verified Models: We check each unit using a Type I calibrator and set the calibration adjustment as necessary to ensure that the unit is as accurate as possible when you receive it. The Verified models include a data sheet that indicates the calibration performance and meteorological conditions under which the calibration was performed.

Verified+ Models: In addition to the calibration check performed with the Verified models, we also measure the on-axis and random incidence performance of each meter in its A-Weighting and C-Weighting modes. A report is included with each unit which compares the freefield performance of the meter with ANSI tolerances. We also include the frequency response data on a mini-CD (FRD format); the data can be used as a correction curve to obtain a flat sound level when used with appropriate PC software.

Sounds good enough for my purposes.

If you had something like an Omnimic at the very least, you would quickly see why the 140 is very limited, and IMO quite flawed, especially in the 20-80hz range......I dunno.....its $125 bucks which isnt big bucks, but for $175 more you can get a tool that is so much more useful...........either way, at least your not using a RS meter, lol.

^ I can't quite tell what they are doing. It sounds like they do calibrate, but only over the ANSI frequency range of the weighting (A/C), which is the way I originally read it. It is not clear if the correction curve is full-range or over the weighting range. If the compensation curve with the CM-140 goes down to 10 Hz or whatever then that should work fine, you just have to manually adjust the levels.

C weighting rolls off below 30 Hz. The compensation may go to 4 Hz but RS meter unit-to-unit variability is a few dB even across the normal range. You need about 13 dB of compensation at 10 Hz to compensate C weighting. Looking at various weighting tables on the 'net it seems like thw weightings may vary with the model year and perhaps the accuracy of the person that made the weightings.

http://en.wikipedia.org/wiki/A-weighting

The RS meter is great for getting an idea of relative levels, and that is usually all that's needed.

Whatever - Don

Cool I wasn't aware that it was a SPL meter too. I'm sure it works great and I've looked at it I guess I'm just cheep I can't justify the price. If what you are using to measure is linier then just how accurate do you need to be. Which is the problem with the RS meter is it's not linier. Unless you send what ever you choose to use off to a cal lab you don't know how accurate it is even your OmniMic, then it must be recalibrated every few years. Do you really need that kind of accuracy can you hear the difference I don't think I can.

Guys; All I want to do is balance channels,see what spl I really listen to and just play around with it. I didn't want to buy the R/s meter because it seemed silly to buy a meter that is so widely known to be inaccurate that there are correction tables available, from people who didn't seem to know anything about it(add to that it's discontinued and nobody knows anything about the new one). If I wanted an oscilloscope function,spectrum analyzer,polar plotting,bass decay function,harmonic distortion and reverberation measurement,and energy-time curves I'm sure you would be a valuable source of information and your input would be appreciated. But.....I just wanted an affordable spl meter.