2. speakers
  3. 162804-149587

Is this how a Subwoofer Crossover is supposed to work?

I bought two Starke SW12 subwoofers that I installed.  So far I'm not particularly happy with them.  They are way too loud even with the volume set almost to off.  More importantly, I'm having trouble integrating them into my system and I'm wondering if that is because their crossover setting is really functioning as I understand a crossover should. Attached please find measurements from Room Equalization Wizard with SPL graphs of the two subs (no speakers) taken at my listening position with the crossover set at 50 Hz, 90 Hz, and 130 Hz. Ignore the peaks and dips which I assume are due to room nodes.  All of those settings appear to actually have the same crossover point of 50 Hz. All that changes is the slope of the rolloff in sound levels. This isn't how I thought a properly designed crossover was supposed to work.  I thought the frequency the levels would start to roll off would change, i.e. flat to 50 hz then a sharp drop, flat to 90 hz then a sharp drop, etc. etc..  But Starke says this is how a subwoofer crossover is supposed to work.

https://www.dropbox.com/s/8x4cr32pagwg48i/Two%20Subs%20Different%20Crossover%20Points%20No%20Speaker...
Any experts on here with an opinion about this?  Is it possible to buy an inexpensive active crossover that I could use in place of what is built into these subs?
pinwa
danvignau's avatar
danvignau
935 posts
 
Yes! That i show adjustable sub crossovers should work, except for the volume problem.
kenjit
1,771 posts
 
That is how adjustable sub crossovers should work, except for the volume problem.
hogwash. Why would anybody design an electronic lowpass filter with a variable slope and a fixed crossover point? Thats useless. What you want is a variable crossover point and fixed slope. Even better would be both variable. 
pinwa OP
239 posts
 
kenjit "Why would anybody design an electronic lowpass filter with a variable slope and a fixed crossover point? Thats useless. What you want is a variable crossover point and fixed slope." 

That is what I thought also and that is what started this whole thread.  But Starke says the subwoofer is designed properly.  And I haven't been able to find any charts that show how other subwoofers respond with changes in the crossover.

Surely some enterprising soul on Audiogon has performed similar measurements on their sub and can post them or knows of a source showing how a "quality" subwoofer works?
erik_squires
15,977 posts
 
You can make anti-modes, or dips controllable with bass traps like GIK Soffit traps, however as Duke would surely advocate, the point of the 2 subs is that the second sub should fill in the big dips, and it doesn't seem like it's happening.  This usually requires non-symmetrical placement.

I suggest you plug your main speaker ports, and re-measure. See if that helps control the peak at ~38 Hz.

Not sure how REW works, but if you are using Roon what I normally do is rip my test signals to my music library, and play the test signals in Roon. This allows me to adjust the Roon PEQ’s accurately.

All of this however is made much harder due to not having a good crossover in place already. This feels like using gum and duct tape and I really think the miniDSP on your sub, plus plugging your mains is your way to glory. Everything else is merely better than before.

pinwa OP
239 posts
 
erik_squires  How would you plug the speaker ports?  There are two of them, each about 4 1/4" in diameter.  The peak at 36 Hz is easy to tame with the parametric equalizer in Roon.  No real need for a miniDSP for that.  But the holes at 61, 77, and 99 Hz are too high for the subs to do much to.  The speakers are in my main living space so I'm limited as to what I can do with bass traps or positioning.  But the truth is the system sounds great. Could it sound better with more treatment?  Probably, but there are limits to what I can and would want to do

There is some trick with REW to measure a signal that REW isn't generating, i.e. played through Roon,  but I haven't figured it out yet..
More to discover