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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
recluse
270 posts
 
Pinwa,
Thanks for posting.
Curious. Did you mention what amp you are using?
erik_squires
16,056 posts
 
I disagree with Erik’s assertion that "if you can’t integrate 1 sub, you can’t do 2. " As the number of intelligently-distributed subwoofers goes up, not only does the in-room response become smoother, but the specific location of any one sub becomes less critical.

Hi Duke,

I don’t disagree that things get smoother, but if you don’t know what 1 sub will behave like, you have no idea of the second is making things better or worse.

Attempting to set crossover points, and delays for both subs at the same time is a lot of work. Far easier to do after you’ve gauged the overall response of a single sub. The FR response of the OP using two subs was, I think you’d agree, pretty awful. Seeing a single sub’s FR would clarify much.

However, it is clear to you, and other experts that 2 subs are better than 1.  :)

Best,

E
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. 
erik_squires
16,056 posts
 
Gah, can’t type today. Or any day. I wrote:

However, it is clear to you, and other experts that 2 subs are better than 1. :)

I meant to say:

Duke, Toole and other experts agree that 2 subs are better than one, and I agree.

I’m just offering up a simple way to get to done from where the OP is, so I am suggesting to measure the single sub FR first. It can’t really be as awful as the first measurement was, can it ?

Of course, a final 2 sub install should be equal or better than 1.
audiokinesis
2,737 posts
 
"Attempting to set crossover points, and delays for both subs at the same time is a lot of work. Far easier to do after you’ve gauged the overall response of a single sub."

Hi Erik,

My experience, and the experiences of many customers who are using four subwoofers intelligently distributed, has apparently been different from yours.

To the best of my knowledge most if not all of my customers have previous and often extensive experience with subwoofers (no newbies as far as I can recall), and instead of integration being far more difficult than when they were using a single sub, many report it to be far easier and faster. Not a single one has reported setup to be more difficult than when they were using fewer subs. And is seems reasonable to me that two subs (intelligently distributed) would fall in between one and four in difficulty of integration.

I don’t dispute your experience, but I do disagree with your generalized conclusion that "if you can’t integrate 1 sub, you can’t do 2", though a different setup paradigm may be called for.

Duke
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