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Sunfire Sub


gsxr1000

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Well I got my Sunfire True Signature Sub about 3 hours ago. Its all tested and set up. Everything works! Luckily the sub came with no feet so it was easy to place it on a rubber mat so it wouldn't "walk". First I tested it with test tones and frequency sweeps. All good. Then some bass heavy jazz (Stanley Clark). I set the sub's volume based on this material. Then some Pat Metheny. Then some Black Eyed Peas - "Boom Boom Pow". I must say I am truely impressed. The Hersey III's just couldn't get there by themselves. The bass notes are clear; you can hear them distinctly as well as feel them. The bass is more 3 dimensional now and you definitely know when the bass player comes in. I've got to say for music this sub rocks. As long as this sub is working properly, I can't believe I'm ever going to need anything better than this sub. I wonder how H3's with a good sub like this stacks up against higher end klipsch speakers with no sub? I am completely happy with this setup for music.

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I have been looking for an SPL meter but haven't found one spec'ed to work below 31.5 Hz. Plus I don't want to spend more that like $60.00. Any suggestions?

I used test tones to guage crossover frequencies and phase. I set the sub's volume by listening to various types of music; some with little base (Yes - Fragile); some with medium amount of bass (Return to Forever - Romantic Warrior); and some with alot of bass (Black Eyed Peas, 50 Cent, Etc). The subwoofer volume control was set to give a pleasing level of bass regardless of the music format. Of course the Rap music really works out the sub, while some Rock not so much. The receiver is set up with the bass control at 12:00. I also switched the main speakers off to listen just to the sub for the various formats. Very clean sound out of the sub. Like I said I am very pleased with the performance of this sub.

As far as using a SPL meter, it would be interesting to see the results to see how well my ears stack up. I would be hesitant to change the volume levels on my sub now as it has taken a long time of listening to find the sweet spot.

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i got a used digital RS one off ebay

granted I really dont know how to use it exactly right so I mostly just use it to confirm my ears. the annoying thing about this meter is it will not display anything below 80 db (must be defective) so I cant do much lower volume testing - and nothing over like 126 db trying to see how loud my car system is :)

All I did was through the receiver test tones I set it where the fronts were all the same at the 0db receiver setting - about 87db on the meter. I have found that with the sub set up about 6db it sounds best to me in my situation at all volumes. So the sub will be reading 93 - 94db and the fronts at 87db with the receiver test tone

just listening to good ole rap music I can get 108 - 109db along all of the back wall in my room (where the couch and chair is) and many random places in my kitchen/dining nook that the living room opens up to. I would like to get a test CD to compare output and frequency.

nothing super crazy loud but plenty to hear and feel it. all from a 13.5inch cube...

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I found this SPL Meter on ebay (TES-1353H) and it is only rated to be accurate between 31.5 Hz and 8K Hz +/- 1.5 db. It is $1000.

I also found correction factors for the Radio Shack Analog SPL meter. They want you to correct like 7 to 20 db for frequencies below 20Hz. But I couldnt find a RS analog meter for sale. It is apparently discontinued now.

Bottom line is I trust my ears and what sounds good much better than SPL meters of dubious accuracy. Maybe I can get an audio professional to come over and test my setup with their meter. Wonder what they would charge for something like that?

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Thanks for the info. The only problem with these meters is they are not rated to perform in the lower frequencies and there are no correction factor tables available to compensate for the inaccuracies. Plus there is variablity in the meter manufacturing process. Even if there were compensation tables, were the tables created to average meter in the manufacturing variablity.

Goldline apparently makes good meters. I think you have to buy separate a microphone though. I think a professional service is the way to go for the least expense.

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oh I agree they are not perfect at all - but it really doesnt matter in any regular home setting because there are too many variables playing against you. You should be able to get a good idea with a basic meter.

and I dont know for sure but I dont think there is much info below 30hz on anything but the lowest movie effects. most of the low bass you hear is 40 - 60 hz range

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Bottom line is I trust my ears and what sounds good much better than SPL meters of dubious accuracy. Maybe I can get an audio professional to come over and test my setup with their meter. Wonder what they would charge for something like that?

[bs]

Watch him bust out a Radio Shack meter while you go fetch your wallet!! LOL

You might trust your ears, but my advice seems to have have fallen on deaf ones.

The correction chart is not because the meters are "innaccurate"...it's because they are C-weighted and the user needs the numbers to take into account the roll-off at lower frequencies. [8-)]

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Maybe I can get one locally but keep the receipt if you know what I mean Stick out tongue

I have a RS analog meter new in box that I can sell you for $25.00 shipped. Send PM with address and I can get it out Fed Ex on Monday.

Bill

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The correction chart is not because the meters are "innaccurate"...it's because they are C-weighted and the user needs the numbers to take into account the roll-off at lower frequencies.

Quote from http://forum.blu-ray.com/showthread.php?t=38765

Corrections to Radio Shack SPL Meter

When using a Radio Shack SPL meter, you need to adjust for the fact that
it's not accurate at all frequencies. Add according to the numbers
listed below. These frequencies are 1/6th octave apart.



10.0 hz: +20.0 db

12.5 hz: +16.5 db

16.0 hz: +11.5 db

20.0 hz: + 7.5 db

25.0 hz: + 5.0 db

31.5 hz: + 3.0 db

40.0 hz: + 2.5 db

50.0 hz: + 1.5 db

63.0 hz: + 1.5 db

80.0 hz: + 1.5 db


Etc Etc

So do we have a discrepency here?

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So do we have a discrepency here?

Nope. Looks about right for C-weighting. [Y] Take into account, many of the measurements we make for home stereo are differential, not absolute. We take a sample, look at the numbers, make an adjustment, and measure again. The numbers are a crumb-trail that allow us to go back to a previous setting if we need to. That allows you to experiment and tweak your setup with a degree of repeatability. Even the most basic of meter will work fine for this, but the Radio Shack has been thoroughly tested over the years, and it's response characteristics well-documented.

Here's a better reference: http://www.prosoundweb.com/article/print/sound_level_meters_the_primer_what_how_why_techniques_more

post-42237-13819692983656_thumb.gif

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Well at least you can see I am not the only one who thought the correction factors were due to inaccuracies in the meter. Thank you for your prosoundweb.com article. I am shortly going to have a Radio Shack Analog SPL meter and I have also ordered a Rives Test CD 2 (Radio Shack Corrections built into the test tones) and I already have a tripod. This should make my experiment as easy as possible. Especially since I only have a 2.1 setup. I am expecting everything to be flat except around the crossover points 5KHz, 850Hz and 80Hz. Has anyone else used the Rives Test CD and procedure? It seems pretty straight forward:

http://www.rivesaudio.com/files/TestCDinst.pdf

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Glad to see you guys connected on a meter and that soon, you'll be in the know. [Y]

I could never understand the stigma attached to using meters. It's not an ego thing at all, ears vs. meters. As if a meter knows when things sound "good". [:^)]

When you get to testing, you use the meter to establish a metric. When you hear what you like, you run a sweep, or listen to few tones and attach a number to that sound. It's so you can say something like, "95dB SPL at 25Hz, at this position is suffieicient." or ,"So that's all it takes at 125Hz to vibrate my couch?" Basic as that... Eventually you'll be able to look at a frequency response chart (so long as the data are complete) and make a pretty good inference about the character of a system.

Couple an SPL meter (SLM as referenced in the PSW article) with a good multimeter and familiarity with your system will climb to a whole new level. Not only can you attach numbers to the acoustic parameters, but with a meter, you can dip into your electronics and see what the signal chain is up to. Knowing what your amps are doing, and when, is not only pretty cool, but allows you to trouble shoot with a degree of accuracy that without, is simply not possible.

For instance, you take your test tone CD, drop it in and run an 100 Hz tone. You put the meter, at your listening position and turn up the amp so that the meter reads 110 dB (corrected). Through all the racket and everything around you vibrating, you hook up the meter across the back of one of speakers, and read the voltage. You read 2V and run the math to pleasantly discover your system is barely idling and it's already pissing off the neighbors ....for example of course. [H]

The skill, and were most of the negativity about measurement comes from, is knowing and always taking into account the limits of the methods (meters, sweeps, etc.) and what the data actually means. Drawing conclusions about performance from information that's simply not there, is a common mistake. Information is empowering and a problem can come about when a half-informed person starts wielding their new-found Broad Axe around in a new forest, in particular, outside of their own. Frequency response charts cannot tell anything useful about transient response for example. Meters measure the room just as easily as the speaker depending on conditions, is another. So there can be pitfalls. The savvy comes from learning about where not to make the errors.

P.S. - I understand that measuring flat from top to bottom may be coveted in the audiophile circles as the "holy grail"of system response, but I hope, with the aid of your new meter, that you discover that flat bass response simply isn't engaging enough for 2 channel music listening. Don't feel bashful after setting your system flat if you find yourself scratching your nugget wondering where all the bass disappeared to. A rising response (or house curve) below ~80Hz is actually very pleasing to most ears. [8]

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