AVS Forum banner
1 - 8 of 8 Posts

·
Registered
Joined
·
4,672 Posts
Discussion Starter · #1 ·
My setup consists of the following:


Display: Panasonic TH-42PW5

DVD Player: Harman Kardon DVD 30

A/V Receiver: Harman Kardon AVR 8500 (named AVR 8000 in the US)

Mains: Klipsch RF-7

Center: Klipsch RC-7

Surrounds: Klipsch RS-7

Subwoofer: Seaton Sound SubMersive


First of all, my room is sealed and about 15 feet long x 11.5 feet wide x 9.5 feet high.


Click the following link to see pics: http://www.avsforum.com/avs-vb/showthread.php?t=1128696


I've calibrated everything with AVIA and The 5.1 Audio Toolkit DVD Mark provided. At reference level, if I play the bass test (you're suppose to hit 115 dB peaks during this test) on The 5.1 Audio Toolkit DVD, I get 112-113 dB from the SubMersive on my RadioShack SPL meter. Since you are suppose to add about 3 dB to the RadioShack SPL meter, I guess that means it's right at 115-116 dB.


As for placement, if you clicked the link above, you'll notice that the SubMersive is right next to the seating area in a corner.


Regarding EQing, I don't currently have an EQ so I guess I'm missing out on that part.


Now that everything it calibrated with the SubMersive running flat (not hot or cold) I played the huge spaceship flyover from Star Wars: Episode II - Attack of the Clones. At full reference level, the flyovers prior to the explosion cause no clipping (the clip light on the back of the SubMersive does not light up). However, during the explosion, the clip light does flicker a bit but the SubMersive does not go into "protection mode."


Since I use to run my main speakers as "large" with the "no sub" option on my A/V receiver when I didn't have a subwoofer, I had something to compare to. Just for kicks, I selected "no sub" on my A/V receiver and set my main speakers as "large" and all other speakers as "small." I ran the bass test on The 5.1 Audio Toolkit DVD at full reference level and achieved 120 dB peaks (which would mean around 123 dB once you add 3 dB to the RadioShack SPL meter). Why is it that even though my mains are properly calibrated, they reached 120 dB (instead of 115 dB after correction) on the bass test when at reference level?


This increased bass from when I ran my main speakers as "large" could explain why I felt there was less bass from the SubMersive once I had my SubMersive calibrated for 115 dB peaks.


Then, just to compare my main speakers' bass output to the SubMersive's, I calibrated the SubMersive to play 119-120 dB on the bass test like my main speakers do when at reference level. I then played the spaceship flyover test at reference and got some clipping this time around during the flyovers and a lot of clipping during the explosion but the SubMersive did not go into "protection mode." However, it seemed the SubMersive was stressing a bit during this higher calibrated level, but I could be imagining things. I feel my main speakers running as "large" with the "no sub" option are more at ease than the SubMersive at these levels.



Am I imagining things or are my main speakers really good at producing bass?



One last question! Is it "okay" to push the SubMersive into clipping? Is it safe to say that as long as the SubMersive does not go into "protection mode," everything it alright?
 

·
Registered
Joined
·
1,395 Posts
When your main speakers are run full range, the SPL meter may be reading the mids and highs at 120dB. I doubt the speakers are putting out more bass than the Submersive.
 

·
Registered
Joined
·
4,672 Posts
Discussion Starter · #3 ·

Quote:
Originally Posted by Eddie Horton /forum/post/17002120


When your main speakers are run full range, the SPL meter may be reading the mids and highs at 120dB. I doubt the speakers are putting out more bass than the Submersive.

I was running the "The Whole Lotta Bass" test on The 5.1 Audio Toolkit DVD. There are no high or mid frequencies, only low (bass) frequencies during that test.


EDIT: Whoops, I just understood what you said. I don't think it matters because when I am testing the SubMersive, all speakers are also playing.
 

·
Registered
Joined
·
6,980 Posts
Hi Kain,


The "Whole lotta bass" track is not meant to be a track to set levels with, but rather it is a torture test track which allows you to listen to what the subwoofer is doing without the higher frequency content covering noises or rattles from your room or subwoofer.


Calibration should be done with the first page of test signals under "Acoustic Test Signals" where you should go through each speaker such that the meter reads 75dB C-weighting, slow mode.


Based on your descriptions of lots of bottom octave shaking and power but you having to turn it up a lot to get big impact, the current location in the room has a good deal of deep bass delivered, but probably a hole or big recession somewhere in the 40-80Hz range. Any subwoofer in the same location will suffer the same relative behavior with the room. While small rooms can provide plenty of deep bass gain, they often have big variations in response vs. frequency, so placement of the subwoofer or the listening position are critical, and EQ can be a big help if you are limited in those options.


This upper octave of the subwoofer range is also what dominates the level settings made with an SPL meter. If the response is low in this range due to the placement of the subwoofer, you will end up setting the subwoofer level rather high at deep bass frequencies relative to the main speakers. This is because the SPL meter is less sensitive at very low frequencies and the noise test signals have less deep bass content to match what the SPL meter reads (at least this is the case on the 5.1 Audio Toolkit you have).


The fact that your main speakers added to the bass level also suggests that the front of the room is more efficient at getting the louder perceived and measured bass to your listening position. The best bet would be to try moving the subwoofer to another location in the room and compare the results. Equalization of some form would be the next plan of attack.


FYI, many subwoofer cry mercy well before reaching 115dB @ the listening position on the Whole Lotta Bass track on the DVD.
 

·
Registered
Joined
·
457 Posts

Quote:
Originally Posted by Kain /forum/post/17002040


One last question! Is it "okay" to push the SubMersive into clipping? Is it safe to say that as long as the SubMersive does not go into "protection mode," everything it alright?

Starting with the easy part first. Yes it is safe to tickle the clip warning light. If your SubMersive could go in to protection mode, that would be safe too, that was the point of it, the amp shuts down before things break. The newer DSP settings are supposed to handle hitting the limits more gracefully than the antiques like mine. If I understand correctly, you will get compression where the SubMersive will play as loud as it can but no louder, rather than a signal cut protection mode. FWIW, it is not easy to get the old school SubMersive to trip into protection mode, I don't think I have ever done it without pushing beyond reference, by more than a few db.


The only thing that I think is not safe with the SubMersive is to run a sine wave at very high output for a long time, as in many minutes. That will build up heat in a way normal material will not. Other than that have at it, Mark designed it to be smarter than his customers, or at least to be tough enough to take the abuse we can dish out.


As for the speakers not straining with the high SPL when set to large, I would assume they have some sort of high pass (electronic or physical) that is limiting the deep bass. The woofers probably are not being asked to play the difficult parts of that scene.


As for the levels, it sounds like you are doing something wrong setting them, or perhaps the processor is not behaving as it should. The mains should see peaks of 105 db max (at reference) no matter if they are set to large or small. The LFE channel is supposed to have a 10 db bump which allows it to go to 115db. I say supposed to because some gear has had bugs with this. What may be happening is your receiver is seeing sub set to small and sending the LFE to the mains which I guess it should do if you tell it you don't have a sub. What it may be doing wrong is adding on the 10 db boost and also sending the same signal to both mains adding another 6 db gain. That would put the max peak level at 121db or so. I don't know what the pink noise is composed of, but if there are higher frequencies in the signal that the mains are reproducing, you may be getting a reading on frequencies above the point where the RS meter is rolling off, hence adding the 3 db may not be appropriate.


I would set your levels using either the receivers test tones or the tollkit tones at 75 db or Avia at 85 db. If you have REW or another graphing system, I would verify with a sweep from 0 to about 500 or so. If you are off by 5-10 db it will be easy to see especially with 1/3 or 1/2 octave smoothing turned on.
 

·
Registered
Joined
·
20,181 Posts
I think Mark said it best, it seems the best placement for your sub would be up front with your speakers. Also, if you are truly getting great bass from your speakers then you may benefit the most with your speakers on large or full range and your subwoofer on to cover below 20 hz. First thing first, place the submersive up front and recalibrate everything flat and listen to how it sounds, then try different crossovers, etc.... Experiment, my subs sound best up front going across the front stage.
 

·
Registered
Joined
·
721 Posts
I think the solution here is a second submersive ;-).
 
1 - 8 of 8 Posts
Top