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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

Showing 2 responses by millercarbon

millercarbon's avatar
millercarbon
12,531 posts
 
The volume control that turns the sound to your speakers up and down must also be the one turning the sound to your subs up and down.

Bingo! And I already provided the simple $2 solution to getting exactly that from his existing amp.
https://www.epanorama.net/circuits/speaker_to_line.html
millercarbon's avatar
millercarbon
12,531 posts
 
pinwa,
First, congratulations on the Moabs. How long you had em? Should sound real nice with that Willsenton. KT88 or EL34? How's it sound? Aside from the subs I mean. 

Sounds like your problem is the line level from the DAC is high enough you're not able to attenuate it down to where you want it. If the Willsenton had RCA pre-outs that would be ideal. Doesn't look like it does. So your solution would be to do like I did with mine and create a pre-out by using what is called a Line Out Converter or LOC.   

An LOC is nothing more than two resistors that serve to drop your amps speaker voltage down to line level. Here is the circuit https://www.epanorama.net/circuits/speaker_to_line.html 

If you remember my Melody amp didn't have pre-out either. What I did was modify one of my extra unused RCA inputs by adding the two resistors to turn them into a pre-out. You can see a photo of the mod on my System page https://systems.audiogon.com/systems/8367 Its not much, very simple. Total cost for the 4 resistors was just under $2. 

If you don't want to mod your amp (its easily reversible btw) then you can make your own LOC for $2, connect it to ordinary speaker wire, put an RCA on the end and plug it in. Or buy the cheap one from Parts Express. Same result either way. This should totally solve your problem. 
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