Eq'ed flat response "problem"

[Vaughan Odendaa]

I'll get a more accurate uneq'ed graph, as the one I posted is incorrect. My levels have been boosted 5 levels above the Eq'ed graph. Inconsistent and unfair.

--Regards,

 

[mtrycrafts]

.... For me at least ideal sound comes from using my ear, but being guided by hard numbers as sometimes we don't realize what we are missing until we hear it.
.

Absolutely. We don't realize it because we didn't have a reference yardstick to listen to. We were used to whatever systems we had, or not, over the many years or decades and we are used to that not knowing what it should have sounded like. So, our reference point is skewed and all over the place.
If we use one disc to EQ to, then all the others will be off, or one will be re-EQing to each disc or song.

 

[AcuDefTechGuy]

The universe is only based on calculus to people who don't know tensor fields

I don't even know calculus now. Forget anything else.
Boy, I can't wait until my two daughters go to high school and they ask me questions about algebra, geometry, and calculus! Oh, no!

 

[Vaughan Odendaa]

I mean, looking at my now updated EQ graph, can you pick out anything that would give rise to the boomy-ish character of the bass ?

I think that one way I'll make use of more headroom is once I disable the subsonic filter of the SMS-1, I'll boost the 15 hz range to make that flat. Then I'll be able to better perceive the infrasonics that are recorded.

WOTW, here I come ! Keeping in mind that my subwoofer is virtually unbreakable, the only possible thing that I could lose is headroom.

--Regards,

 

[avaserfi]

avaserfi, what subwoofer do you have ? Would you be able to (or anyone) to verify that my results are normal ?

I know that it's a bit of an undertaking (actually one heck of an undertaking) but if you could eq your system flat and then calibrate flat with the mains, could you tell me whether you get felt impact on your favourite movies ?

I just can't believe that a single PB10 can get the most from these films at reference when I can't feel a thing from them. Tried The Incredibles, tried Master and Commander, tried Matrix Reloaded (and Revolutions).

100 odd db's down low should give me considerable felt action.

--Regards,

Its a Jamo Sub650 (listed in my sig). I have not perceived a decrease in my room pressurization with my sub equalized. Although my room is a bit smaller than yours.

My sub is as flat to the 80Hz crossover where my mains engage as it will get given my current situation and I enjoy movies greatly with it although I will likely be trying out a house curve when I have time.

Perhaps someone can answer this question. Is there a reason why once my response has been equalized, the bass while sounding much fuller also sounds more boomy ?

The bass is likely boomier now because there is more of it in the room at certain frequencies than there was before to be reflected in the corners and to some extent off of the walls so I would recommend treatments to deal with this boominess which will increase decay and give you a far tighter sound.

Also, it seems that you are completely missing the point many people are trying to make here and only reading into what you want.

So here is me repeating myself:

Just because your frequency response is flat does not perceive it to be so. Human hearing is not linear in the lower spectrum which is why many prefer a house curve. You should really try and get away from having "perfect" and focus on getting what you enjoy otherwise you will constantly be striving for something you dislike and what is the point in that?

If you want a more full low end during movies set the EQ to a house curve and apply it solely during movies using a flat eq for music.

 

[Vaughan Odendaa]

The bass is likely boomier now because there is more of it in the room at certain frequencies than there was before to be reflected in the corners and to some extent off of the walls so I would recommend treatments to deal with this boominess which will increase decay and give you a far tighter sound.

Alright ! Now this would explain the slow character of the bass. There is a lot more of it in the 50-80 hz range but the decay times are being overly pronounced because of modal resonances.

Also, it seems that you are completely missing the point many people are trying to make here and only reading into what you want.

Respectfully, that isn't the case at all. Perhaps you haven't understood the crux of my specific situation.

In fact, no one has offered an explanation as to how my subwoofer is somehow able to play back material at reference level (all details as per calibration are on page 1 and 2) with virtually no felt impact especially considering that I am able to increase the sub level by 3-4 dB's above calibrated level which gives me greater audible impact on almost all deep bass segments.

All that I wanted is to understand why my results were underwelming especially given that I now am listening at reference level and the fact that my subwoofer should be putting out a heck of a lot more than it should. The levels that I should be hitting at reference I'm obviously nowhere near and yet I can still calibrate to higher levels with no problem. It's almost as if reference level playback is a breeze on my system (except there is virtually no pressurization or low end impact).

As I said, I probably will try out the house curve but until I get to the bottom of my "flat FR /max output anomaly", I can't do it just yet.

Thank you for your suggestions on the house curve. That probably will clear up most of the low end problems but it still doesn't explain what I am currently experiencing with my setup.

Thanks again.

--Regards,

 

[avaserfi]

In fact, no one has offered an explanation as to how my subwoofer is somehow able to play back material at reference level (all details as per calibration are on page 1 and 2) with virtually no felt impact especially considering that I am able to increase the sub level by 3-4 dB's above calibrated level which gives me greater audible impact on almost all deep bass segments.

All that I wanted is to understand why my results were underwelming especially given that I now am listening at reference level and the fact that my subwoofer should be putting out a heck of a lot more than it should. The levels that I should be hitting at reference I'm obviously nowhere near and yet I can still calibrate to higher levels with no problem. It's almost as if reference level playback is a breeze on my system (except there is virtually no pressurization or low end impact).

I believe that the pressurization and physical impact you seek from your sub are not only tied to SPL out put but room interaction. The felt impact you seek from your sub seems likely due to the fact that you have such a small subwoofer in such a large room. Perhaps the subwoofer is not producing enough impact to properly interact with the room and pressurize it in the way you seek.

I am not too familiar with SVS subs and the rooms they belong in, but it seems that the PB10 ISD would be their bottom tier which is why I recommended acquiring another sub as this would help pressurize your room and give you that tactile feel we all love from our woofers.

One reason you might have felt this pressurization previously and may have lost it after equalization was possibly due to peaks in output that are no longer present hence my suggestion of a house curve which might increase room pressurization via higher SPLs.

Hope this helps!

 

[Vaughan Odendaa]

Thanks for your comments and suggestions avaserfi. Much appreciated !

--Regards,

 

[avaserfi]

Thanks for your comments and suggestions avaserfi. Much appreciated !

--Regards,

Not a problem at all. Glad to see I managed to answer the real question at hand! Be sure to keep us updated on your experience with the SMS-1!

Also, just an FYI I think Clint added the "thank you" button to cut down on clutter in threads so people don't have to post "thank you" all the time. Have a good one .

 

[Vaughan Odendaa]

BTW, you say that you don't perceive a decrease in room pressurization. Is that because you haven't touched the really low end stuff but concentrated more on the upper bass (from 50 hz up until the crossover frequency ) ?

I would be very interested to learn how you eq'ed.

It also got me thinking. Perhaps the test tones on my AVR are somehow inaccurate. I have a Yamaha RXV-450 receiver. Is it possible that perhaps the tones are not accurate ?

I also think that I should get a more accurate SPL meter. If I want to calibrate to 75 dB's with pink noise then my current RS meter is rubbish because you still need to enter correction at low frequencies.

But if I purchased the Galaxy SPL meter which has a much more accurate low end response, would reading pink noise likewise be more accurate than the Radioshack or would the meter still peg the needle like the RS ?

--Regards,

 

[Vaughan Odendaa]

I guess I now need to get some gigantic bass traps to fill the room corners.

Oh boy.

--Regards,

 

[Vaughan Odendaa]

Not to take anything away from avaserfi, as his advice and suggestions have been excellent and informative, but my prime concern I described on page 1 has not been addressed. I'll thank you later, avaserfi.

Heh.

Alright. Let me give this one last stab at it. Perhaps my communication skills are lacking. But I'll make one last attempt and then I'll go to bed. Alright. Reference level bass gives you 115 dB's at the listening position.

If speakers are set to small, the redirected bass from the main channels will then sum with the LFE bass information which would then yield 121 dB's at the listening position. My specific concern is that when playing back the "heavy hitters" at reference, there is virtually no felt impact but when I increase the levels even more, I can sense some form of impact or pressurization.

What bothers me is that it is already established that it's virtually impossible, due to physics, for my subwoofer to achieve the levels that I am talking about. So then how is it possible that when I increase the sub levels by 4-5 dB's over and above my current settings that the bass has far more impact (which is the equivalent of increasing MV 4 to 5 clicks over and above reference level).

Hopefully now you'll be able to understand the problem that I am experiencing. It's a really, really odd problem.

--Regards,

 

[AcuDefTechGuy]

But if I purchased the Galaxy SPL meter which has a much more accurate low end response, would reading pink noise likewise be more accurate than the Radioshack or would the meter still peg the needle like the RS ?

The Galaxy Audio SPL meter is digital so there is no needle: http://www.bhphotovideo.com/c/product/333306-REG/Galaxy_Audio_CM_130_CM_130_CHECK_MATE_.html

The increment is 0.5 dB, not 0.1 dB.

 

[avaserfi]

BTW, you say that you don't perceive a decrease in room pressurization. Is that because you haven't touched the really low end stuff but concentrated more on the upper bass (from 50 hz up until the crossover frequency ) ?

My room is far smaller than yours (less than 2000 SQ FT) and I mainly had minor dips to fill (nearly cubic room) throughout the response range rather than hills to tame. So after equalization I feel more bass response rather than less. Also, I enjoy my bass slightly hot so I run my sub at 4dB above my other speakers.

It also got me thinking. Perhaps the test tones on my AVR are somehow inaccurate. I have a Yamaha RXV-450 receiver. Is it possible that perhaps the tones are not accurate ?

I doubt the tones are inaccurate, but you could always get a test disc, but remember test discs are set at different levels for example Avia is set at -20dBFS and receivers are generally at -30dBFS.

I also think that I should get a more accurate SPL meter. If I want to calibrate to 75 dB's with pink noise then my current RS meter is rubbish because you still need to enter correction at low frequencies.

But if I purchased the Galaxy SPL meter which has a much more accurate low end response, would reading pink noise likewise be more accurate than the Radioshack or would the meter still peg the needle like the RS ?

From what I understand the Galaxy SPL meters are a bit more accurate than Radioshack ones, but I wouldn't get caught up in this problem. There are more important things to address here like room acoustics .

What bothers me is that it is already established that it's virtually impossible, due to physics, for my subwoofer to achieve the levels that I am talking about. So then how is it possible that when I increase the sub levels by 4-5 dB's over and above my current settings that the bass has far more impact (which is the equivalent of increasing MV 4 to 5 clicks over and above reference level).

Hopefully now you'll be able to understand the problem that I am increasing. It's a really, really odd problem.

Room modes most likely account for these SPL levels. When I first hooked my sub up and used REW I was getting usable SPLs down to 14Hz due to room interaction (my sub is rated down to 24Hz). When the waves are bouncing around in a room they can add or subtract for eachother you are likely getting some major wave on wave interaction (ohh yeah thats right ) in the positive direction. You need to remember: most SPL levels for subs are from anechoic chambers which act completely differently than a room.

P.S. Vaughan I tried to PM you but your box is full.

 

[Vaughan Odendaa]

[Room modes most likely account for these SPL levels.

Here is a rookie question for you. Wouldn't the SMS-1 graph account for the peaks and dips from said room modes ? And so equalizing the response would have addressed the modal peaks that room modes would exhibit, correct ?

If you looked at my graph on page 2, you'll see that I had, pre-equalized, a healthy boost of output between 20 to 40 hz. But if I cut those down then the room modes contributing to the reinforcement at those frequencies would then have less energy.

What are your thoughts on that ? Oh, I'm starting to get real tired, real fast. I forgot the time is only 05:19. Over here in South Africa it's 12:20, midnight. Time for bed.

Thanks for your contributions avaserfi's, I really do appreciate the time you've taken to respond to my questions. Hope I haven't been too much of a burden. To all those who responded, thank you.

I'll post back here tommorrow with some updated graphs.

--Regards,

 

[avaserfi]

Here is a rookie question for you. Wouldn't the SMS-1 graph account for the peaks and dips from said room modes ? And so equalizing the response would have addressed the modal peaks that room modes would exhibit, correct ?

Very good point, but in accounting for the room modes it does not stop them just properly equalize to account for them. This means that your subwoofer will be able to have higher output than its anechoic chamber response because it is interacting with the room.

Basically the room modes are accounted for via the SMS-1 giving you a flat frequency response, but the room interactions do not go away which means the interactions that give you a higher output than expected still exist. The problem is your subwoofer might not have the capabilities to pressurize your room as you would like.

Glad to be of help. I enjoy your questions as I either learn by reading responses or learn because I have to look up some answers for you . Hope this helps, let me know!

 

[Vaughan Odendaa]

I enjoy your questions as I either learn by reading responses or learn because I have to look up some answers for you . Hope this helps, let me know!

Heheh, you are a funny guy. We'll chat tommorrow. Good night !

--Regards,

 

[ParadigmDawg]

Oh dont get me wrong; I would love to get the "most" out of my system. I am waiting until your Christmas break before I order the SMS and you are coming over and doing all the nasty work

Very good point, but sometimes without those numbers you don't always know what you are missing. Before I started equalizing my sub and working with its placement I never realized how much bass I was missing. My system sounded good to me, but I didn't realize how much better it could sound! For me at least ideal sound comes from using my ear, but being guided by hard numbers as sometimes we don't realize what we are missing until we hear it.

Vaughan I strongly recommend you trying out a house curve at least for movies. It will likely help with your room pressurization issues and fill in the low frequencies you are looking for. As we delve into the lower octaves higher SPLs are needed for humans to perceive equal responses thus people use house curves. With your given room size and subwoofer you should be careful not to bottom out the woofer. Perhaps adding another and then using a house curve would be ideal as it will give you more output, pressurization and allow for an even flatter frequency response.

As Greg said just because your line is perfectly flat doesn't mean it is "perfect" experiment until you find something you like don't seek perfection just to have it in spite of what you like. You are shorting your self by doing this.