# broken SPL meter or unrealistic expectation? max spl of 90-95ish



## Talley (Dec 8, 2010)

Finally looked at my SPL meter with the sub playing some sine waves from 16hz to around 100 or so. there was one tone that did have a boost up to around 95 but for the most part the max I saw was around 90 and that was with the volume cranked to +8. My HSU sub was set to maximum headroom 1 port open Q.7 and even switched to maximum extension.

lots of port noise at 16hz and the wind coming from the sub was very easily felt at 11' away when in front of it. 

My room is 14.25x20.75x~10' (cathedral ceiling). My cu-ft is around 2900.

Seems kinda low don't it. the walls in the room was literally shaking though.

maybe I have a busted meter? it's only 17 years old.


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## Talley (Dec 8, 2010)

Here is the layout and where my sub sits. I had it in center mainly for localization testing. 

So... would I see a significant gain moving to outside either one of the L/R speakers? I really need to add a second sub and that would help with localization.

One thing I haven't done is the subwoofer crawl with a meter or anything. Just set it and this is where it was put.

Maybe I need to start moving things around.


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## willis7469 (Jan 31, 2014)

Was it "c" weighted and slow?


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## Talley (Dec 8, 2010)

willis7469 said:


> Was it "c" weighted and slow?


c weighted is for lower frequencies it's a switch on the SPL meter. the other switch is a slow/fast response and just gives the needles response time.


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## tonyvdb (Sep 5, 2007)

corner loading a sub will boost the output but usually not in all ranges. 95db is not bad considering the sub you have.
16Hz is punishing for just about all subs. Dont expect that frequency rang to be at reference (105db) unless you have something bigger.


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## willis7469 (Jan 31, 2014)

Bmxer241 said:


> c weighted is for lower frequencies it's a switch on the SPL meter. the other switch is a slow/fast response and just gives the needles response time.


 I was just checking if you had it set that way. I was gonna suggest the corner too. It's easy to try, but you might want to wait for your mic. My 3 subs are corner loaded and have a pretty smooth rise in output from 80hz to 20hz, by about 10db. I call it my own little house curve. Lol. 2subs are behind the LP. Can't even tell. I did that because my overall space is pretty big. Worked out.


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## Tom V. (Jul 12, 2012)

1)add about 10dB to the RS SPL meter reading at 16hz. 

2)sine waves at loud levels can easily damage a subwoofer and this won't be covered under warranty in most cases.

3)sine waves are not a good tone to use to determine max output. Music and film is transient in nature. I would add at least 3dB to your SPL readings...maybe as much as 6dB depending on how the amp limiters are reacting to this abuse..

Tom V.
Power Sound Audio


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## willis7469 (Jan 31, 2014)

Good point from Tom. There is an offset chart somewhere at HTS. You can use your spl meter as a mic also until your umik shows up. Tell rew which one you have, and enter the cal file. .....or wait. Lol


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## Talley (Dec 8, 2010)

I'll wait. I'm patient.

and I don't wanna screw up my sub so no more sine waves.

I'll report back when I get the mic and find a better spot for the sub.


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## Wayne A. Pflughaupt (Apr 13, 2006)

Bmxer241 said:


> Seems kinda low don't it. the walls in the room was literally shaking though.
> 
> maybe I have a busted meter? it's only 17 years old.


You do realize that the meter is C-weighted and as such its response rolls out below 60 Hz? For instance, assuming the meter is accurate (probably an unreasonable assumption), a 16 Hz sine wave tone is going to register 10 dB lower than it actually is.

By the way, my experience is that center-of-wall sub placement gets poor response, as there is no corner reinforcement and the potential for nulls is greatly increased.










Regards,
Wayne A. Pflughaupt


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## chashint (Jan 12, 2011)

As previously mentioned sustained sine wave testing is brutal on any speaker and most speakers/subs have fine print in the warranty that prohibits doing this.


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## Talley (Dec 8, 2010)

chashint said:


> As previously mentioned sustained sine wave testing is brutal on any speaker and most speakers/subs have fine print in the warranty that prohibits doing this.


10-4. Was not aware and will not do this again.


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