Who uses an active electronic crossover with their subwoofer(s)?

Watching everyone’s favorite audio goofball, OCD HiFiGuy…

Whether you like him or not, he’s got an interesting vid on active crossovers… He’s got his Magnepan .7’s set up with his subs and an active crossover, so the maggies get no bass frequency below, ahdunno, 80hz or so.

Pretty impressive to hear the difference before and after.

I know @paul has a video or two about them, but anyone else use one? And if so, care to share the details about the device and how you have it set up? Interested more in crossovers between speaker and sub, rather than between individual drivers within one loudspeaker.

For the most revealing “test” go to these three timestamps in the video:
Bass Check 2:05 3:53 10:26

Full video here:

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Not me, but I will be once I have saved up for a pair - I’m set up already with the crossover corossing between “hiss” and “oi”/“honk” on the main system. I do have a thought though (and apologies I seem to be very chatty across the forum today!).
I am aware of, and of course respect, Paul’s oft-said statement that it is better to hook the sub using high level to the main speakers. However it seems to me that is both a waste of main amp power, and risks harmonic distortion from the low notes within the main woofer being audible further up the spectrum (I think that woofers have higher harmonic distortion on the very low notes).

line level crossovering removes this load from the main woofers so ought to improve things,
it used to be that way back in the day on tri-amped sound re-inforcement anyways - going to quad-amp and removing sub-80 ish Hz from the main low end drivers was a Good Thing ™.
as it cleaned up the overall sound.

Now I’ll shut up and let folks with relevant HiFi experience speak :slight_smile:

Yeah, it’s interesting. That’s the REL company line, too.

I’m mulling over new subs behind the maggies, and RELs are definitely in the mix. Not sure I’d use the high-level speakon connections, or stick with the trusty low-level ones. You may have noticed that OCD guy is dead set against the high-level option, for the exact reasons you mention.

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I use a MiniDSP with 4 subs and calibrated with REW. Then tweaked by ear. I find the crossover and level controls essential and it easy to tweak the subs when I want to adjust for a particular song or album.


JL Audio CR-1 on crossover duty followed by a Xilica DCP-3060 dedicated to subwoofer PEQ.

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For both my main and desktop systems I use all-in-ones (Boo! Hiss! Go stand in the corner!). Both have LFE outputs and the ability to switch them on and cut out low bass from the speaker feed. On the Arcam the frequency at which this happens is configurable down 50Hz (too high for my TL speakers) and on the Powernode 2i it is fixed at 60Hz (too low for the P3ESRs). In both cases setting up the sub using LFE to blend seamlessly with the speakers is impossible; you get dips or bumps in the SPL for the frequency range. By using a high level input for the sub I can get the response of the system pretty much flat down to 20Hz. I prefer my speakers to do as much work as they can, since they are designed for that, and just use the sub to fill in the bits they can’t reach.

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I have a friend who has a Trinnov and it sound awesome to my ears. I would love to own one.

I was unable to get enjoyable integration of subs into my two channel system using several speakers and two different subs. Until I added the JL Audio CR-1 crossover.

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Yes to crossover (I use a CR-1 from JL Audio) with two JL subs. However, the subs and mains MUST be phase corrected (At the crossover frequency setting such at 80 Hz) to get the full and jaw-dropping benefits.
Also, regardless of what you might think (intuitively) start with a crossover setting of 80 Hz. I have 4 12s in each main speaker and still crossover at 85 Hz (due to room mode in that area, so that I can adjust the Q). This lets the JLs do their job and let’s the main speaker woofers and PSA monos play with more ease.

On my older system an active electronic crossover box came with my Infinity Modulus system. RCA output from preamp out to Infinity box, and RCA’s from Infinity box to power amp. The box has it’s own cord to the powered Infinity sub. Have it set at 90hz with volume level adjusted by ear. With my newer system the speakers run full range (no active crossover) and the upper range of the subs is currently set at 50hz

Once again I am educated by other folks experiences, I do like this forum :slight_smile:

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I use a DSPeaker X4 to integrate my 2 subs and speakers- like it a lot.

Mmm, I think you’re confusing what Paul (and REL) recommends. Yes, it’s the high-level signal from the ‘mains’ amps feeding the subs, but it’s not the mains amps powering the sub rather the subs amp(s) driving the woofer. This presents a negligible load to the mains amp. Unless the sub is passive which almost no ones does anymore because of what you said.

The high-level signal is used so that the subs get the exact same wave form as the mains as they come from the same ‘source’.

I think the title/question would be better stated ‘who uses a crossover to roll of their mains instead of allowing them to naturally roll off?’

I use sealed mains and sealed subs, feeding the subs the same high-level signal from the mains amps. They blend as magically as can be as the slope is configurable in my active subs, along with phase/delay and gain, of course. Clear as mud?

My subs don’t have a high-level input so I inserted a Jensen transformer to accept the high-level signal and feed the sub the low-level it can accept. It was one of the absolute best changes I ever made to my system.

Yeah I know it’s just a feed that is then amplified separately in the sub, but it doesn’t prevent the main Amps still trying to drive the woofers in the main speakers lower than they can handle, however I may have overestimated the impact this might have on the overall sound. It does as you say mean the subs get whatever colouration and or phase shift the main Amps do, which seems to be a good thing for integration:)

Right, but the woofer in the mains is the job/problem of the speaker designer? I would go by what they recommend regardless of a sub or not.

The mains will have a natural rolloff and I think it’s best to let them do this and then using the sub(s) controls to match the slope and frequency of the mains natural rolloff as opposed to actively rolling the mains off when the designer didn’t intend for this to occur.


And this is why I am here - when you put it like that it makes perfect sense :slight_smile:

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