[guf]

HO SAMs and a rythmik 12 inch sealed GR sub, near field and crossed over at 120. I think it’s sounds wonderful, balanced, and dimensional.  I turned it up the other day because a friend suggested because we were listening to a 6 string bass player and he plays higher notes. I forgot about it and was wondering why I enjoyed my listening so much last night. Seems unconventional. Is his theory correct? And am I liking the movement or air and feeling at the expense of accuracy?

[oem-wheels]

I too cross it over at 120 and enjoying the sound... It was suggested to me to try this because so little goes down there below 120 anyway.. By doing this , you lighten up the load to the amp that powers you R/L speakers (and speakers) and will allow it to perform better.. I use monitors.. Maybe towers a different story..

[JLM]

120 Hz is smack in the mid-bass range.  There plenty going on below 120 Hz (2+ octaves of music).  But yes, if you filter the bass out before sending the signal to the amp running your mains (HO SAM's) then it would lighten the load to that amp and your mains.

What frequency were you crossing over at previously? 

Not the HO SAM's, but many smaller monitors lack mid-bass 'body' that would be solved by crossing over at 120 Hz.  Depending on the geometry of your room/setup you could be alleviating room induced bass echo the room, creating a 3-source swarm (search Audio Circle for "swarm").  Another reason for preferring the higher crossover frequency could simply be the more the better effect.

[oem-wheels]

try this...  crossed over at 120, walk to your sub and feel how hard its working ? mine, not much.. a good reason why I'm letting the sub handle everything down at the 120 mark.. I don't fully understand everything that goes on in the frequency range as to where the instruments reside in but I read that the kick drums can operate between the 60-300Hz and sometimes higher and even lower.. I still hear kick drums through my monitors and with punch..

[artur9]

I have mine so to 110Hz although my mains measure down to about 70Hz.  I like the extra clarity offloading the mains give.

[sunnydaze]

....... Seems unconventional. Is his theory correct? And am I liking the movement or air and feeling at the expense of accuracy?

Why overthink it so much?    

If it sounds better to you, it is better.  Does it matter why?   Just enjoy whatever is the most pleasing.

PS:   I high-pass my Omega Super 7 XRS at 100 hz and play my sub (Gallo CLS-10) up to 140 hz.  Sounds great.....much better than running them full range sans sub, or full range w/ sub added to the bottom.

[mikeeastman]

I recently changed my setting from 80 hz to 100 hz on my GR Research sealed sub I high-pass my Super 7s at 80 hz. The impact of my base jumped a couple of notches. 

[roscoe65]

I recently changed my setting from 80 hz to 100 hz on my GR Research sealed sub I high-pass my Super 7s at 80 hz. The impact of my base jumped a couple of notches. 

There is a big value to having overlap in the 80hz region.  This is the region responsible for a lot of our bass perception (the fabled “chest lock”).  We can also accommodate assymetric crossover slopes (such as 4th order for low pass and 1st order for high pass) that help localize the image to the mains.

[DaveC113]

IMO, ideal would be ~200 Hz but then they're woofers. 

[roscoe65]

What most of us want are really helper woofers rather than true subwoofers.  My Omega’s are helped out by a pair of Rythmik F8 “subwoofers” blended in at about 180hz.  Stereo subwoofers make this easier, but overlapping the mains really helps as well.

[Jazzaudio]

try this...  crossed over at 120, walk to your sub and feel how hard its working ? mine, not much.. a good reason why I'm letting the sub handle everything down at the 120 mark.. I don't fully understand everything that goes on in the frequency range as to where the instruments reside in but I read that the kick drums can operate between the 60-300Hz and sometimes higher and even lower.. I still hear kick drums through my monitors and with punch..

[oem-wheels]

Nice....  thanks Jazzaudio.. now I need to figure out how I can save that diagram for my wallpaper or screen saver (or whatever they call it) for my computer..  anybody looking for a test cd for bass ? find a band that uses a harp or a tuba, or BOTH.. wow..  that should be fun..   Little confused as to how the kick drum can spread across the spectrum ? is it where it changes color is where the medium is for that instrument ?

[roscoe65]

Nice....  thanks Jazzaudio.. now I need to figure out how I can save that diagram for my wallpaper or screen saver (or whatever they call it) for my computer..  anybody looking for a test cd for bass ? find a band that uses a harp or a tuba, or BOTH.. wow..  that should be fun..   Little confused as to how the kick drum can spread across the spectrum ? is it where it changes color is where the medium is for that instrument ?

There is no standard kick drum.  They come in different sizes and can be tuned.

[doggie]

There is a big value to having overlap in the 80hz region.  This is the region responsible for a lot of our bass perception (the fabled “chest lock”).  We can also accommodate assymetric crossover slopes (such as 4th order for low pass and 1st order for high pass) that help localize the image to the mains.

What are you using to high pass?

[oem-wheels]

"There is no standard kick drum.  They come in different sizes and can be tuned"

thanks, I know they all don't sound the same but near the tweeter region ?

[RDavidson]

Yes, the initial "whack" on the drum is actually quite high in frequency, but obviously drops quickly into the resonant bass tone that bass drums are known for. Pipe organs and electronic bass are much different, in that they only produce the bass tone (no "whack"). Sorry for my unscientific explanation. I'm tired and don't feel like looking up the actual terminology for all this...though you likely understand what I'm talking about.

[oem-wheels]

that was good RDavidson.. I'm tired too and if you used the terminology I'd have to get up and fetch the dictionary..

[Jazzaudio]

OEM,
I can't remember from where I copied this chart, but similar ones are online, and are more associated with recording/mixing sites.  I love them because they remind me why I listen: music! 

If I recall correctly, the entire horizontal bars are the audio frequencies produced by the instruments, with the red portion of the bars representing the fundamentals and the yellow portions the harmonics. Both affect tone, help us identify what instrument we're actually listening to, and are a function of instrument design, tuning, or both. The kick drum signature you're hearing through your monitors are the upper harmonics. Seeing (from the chart) the kick drum's harmonics start at about 500hz and represent half of the total range of the drum (up to about 8khz), it would make sense you hear it through your monitors. Or, more importantly, you should hear it!

Roscoe and JLM bring up great points about the 80hz region being responsible for a lot of our bass perception, and the 120hz being smack in the mid bass range and related to mid-bass body.  If you look at the narratives near the bottom of the chart, 80hz is near the middle of the zone often subjectively associated with a sound having "body," and 120hz is in the range subjectively associated with "boom/punch." JLM points out allowing a subwoofer to carry more of the load up to 120hz (through both the subjective "body" and "boom/punch" ranges) could compensate for the lack of  "body" in some monitors. The chart supports what both said 100% (not that they needed to be validated!)

Here's a interesting way of looking at the chart. It lists the kick drum's range (fundamentals and harmonics) as 50hz-8khz.  If you take the midpoint of that range and follow it down to the subjective descriptions near the bottom of the chart, you'll end up between the subjective "fullness/mud" and "whack" and "tinny" sounds.  Many of the frequency ranges contain both positive and negative subjective narratives. Which description actually applies depends on how the instrument should actually sound (by design or tuning), or ones personal preference.  The midpoint range of the kick drum actually falls in the subjective "honk" sound...but since the kick isn't a brass or a woodwind instrument this may not apply  But that midpoint includes the "fullness/mud" subjective range, but does not include the "whack" or "tinny" ranges. 
However, all the descriptions fall within the total range of the kick drum.  The key is the midpoint, or the balance of the instrument...as reproduced by the audio system. Perfectly reproduced, the kick drum would sound full (balanced.) But under-reproducing the lower frequencies and/or over-reproducing the upper frequencies would shift the midpoint toward the "whack" "tinny" range.  Doing the opposite would shift the midpoint towards the "mud" range.

Another thing I like about the chart is how it highlights what we hear so much about: the midrange.  Notice how often the transition between fundamentals and harmonics occurs in the midrange.

[jMelvin]

Here's a similar version of the frequency chart:

http://sineworld.com/html/basic_knowledge/freqchart.html

[JLM]

Acoustically there are a number of factors to consider regarding at what frequency to crossover to a sub:

-  bass capacity of the main speakers (to ensure mid-bass "body" isn't lost)

-  localization of bass notes (the ubiquitous THX standard of 80 Hz)

-  the Schroeder frequency of the room being used (where sound waves transition from behaving as waves to rays)

-  is bass being filtered from main speakers/power amp (a concern for small amps)

Note that the Schroeder frequency is typically around 130 Hz and so an ideal solution may not be possible.