If you calibrate to specific levels, then what difference do better subs make? (1 Viewer)

[Chris Rock]

I am searching for a technically accurate answer. I just calibrated my system with the help of a friend, and he asked me why I got a new sub (JBL PB 12). I told him that the frequency response was better, it has a larger woofer, and more power than the old one (an 8" 100W Kenwood HTB sub).

The question came up - if you're calibrating the system to specific listening levels, than why does it matter what sub you have, provided it can reach those listening levels and be balanced with the rest of the system.

I couldn't come up with a technically correct answer, but I know that my new sub sounds better than the old one.

Can someone help me? I'm being totally serious, here. Knowing this answer will help me when I upgrade to a better sub in the future.

 

[Vince Maskeeper]

1) While overall "volume" might be the same- the goal is to have accurate level over the entire freq spectrum. Better subs will go lower, where cheaper subs will simply roll off the really low stuff. While the volume of an overall filtered pink tone might be the same--- you will never listen to pink noise in your system. The response levels at specific freq will vary greatly, which will be a telling issue during playback of actual program material.
2) The metered pink noise volume might be the same SPL overall- but the goal is to have flat response. Cheaper subs tend to be more boomy in certain freq, so while the meter will measure the same- it's measuring the boomy freq sticking out. Nicer subs will give more flat response.
(see my post here: http://www.hometheaterforum.com/htfo...999#post429866)
3) The biggest problem with cheap subs is running out of headroom in the driver or amp. Most commercial subs include some sort of limiter in their amp stage- meaning you are probably hitting max on the sub and not even knowing it- the limiter is limiting the signal to prevent the sub from bottoming out. Have serious amplifier power, and nicer drivers will give you full powerful playback without squashing the signal with a limiter.
4) The above is also true about distortion. Cheaper subs tend to burp out more distorted signal due to limitations of the driver and the amp. This distortion isn't necessarily as obvious as distortion on midrange- rather is a smearing of the lows into a boomy nasal sound. Most cheap subs I hear have some degree of distortion, and some people actually prefer that sound as it sound more like bass you get in a cheap car stereo.
5) Of course there is also the issue of build quality and logevity that is at issue when buying anything "nicer" than the walmart brand.
There's a few to get you started, I could probably do a dozen if I had more time.
-Vince

 

[RichardH]

Vince hit the main points. There's also the issue of transient response. Better subs will give you better pitch definition.

 

[Chris Rock]

Thanks for the answer, Vince. Your points make a lot of sense.

I love the HTF.