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Looking for a crossover/high-pass solution for integrating mains and powered subs

S

sooner8888

New Member
I would like to crossover/high-pass my mains so they are spared frequency demands of 80Hz or so and lower. It would be a bonus to also prevent the power amp from being asked to deal with the demand of these lower frequencies.

Currently...
I have a pair of KEF passive LS50s, and a pair of SVS SB12-NSD powered subs. My system includes a Schiit Freya+ preamp with one pair of RCA outputs feeding the subs directly, another pair of XLR outputs feeds an Anthem power amp which feeds the LS50s.

I want to limit the full range signal to the LS50s, and let the subs handle all the bass.

I could route the signal from preamp to subs, then to power amp, then LS50s, and use the sub's active crossovers to highpass the power amp/LS50s. However, since the subs are RCA only, I cannot use the XLR outputs from pre. Freya+ has passive, JFET buffered and tube buffered modes. I use the JFET mode for most of my casual listening to extend the tubes' life, and Freya+ performs noticably better in JFET with balanced connections, so I'd prefer to use balanced XLR outputs from pre.

What to do?

Are there audiophile-ish quality active crossover I can route everything through, and incorporates balanced XLR? Bass blockers?

I thought about miniDSP with XLR, but as I often do my critical listening though Schiit Sol turntable, it doesn't make since to me to convert analog to digital and then back to analog. Am I overthinking this solution, or overly concerned about degradation of the analog sound quality with all the signal conversions?

I've considered pro audio solutions, like the dbx DriveRack, but these can be noisy, and lots of extra circuitry for the signal to pass through getting "dirty" all the way.


Setup...https://imgur.com/a/UrdCv75
 
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I have used a pro audio (Rane) crossover without any problems. XLR to RCA cables made the connections easy.
 
I currently use two electronic crossovers, one for front and one for rear. Both are "pro" and need RCA to XLR adaptors.

An electronic crossover and multiple power amps have been part of my system for 20+ years.

As for an "audio quality" crossover, it depends on your desires and wallet. There are electronic crossovers that cost $100. There are also ones that cost $2000.

Investigate and buy whatever you think is best for your purposes.
 
I would suggest a miniDSP 2x4 ( https://www.minidsp.com/products/minidsp-in-a-box/minidsp-2x4 ) which lets you configure the 4 outputs - 2 with high pass for the speakers, and 2 with low pass for the subs. You can experiment with the crossover frequencies and slopes. This is single ended, so that is not helping get anything balanced.

I am using the 2x4 HD as an active crossover with my Linaeum LT1000, and it adds the ability to have custom EQ, which can correct frequencies that may be too high. It can pull up small drops in response; but is better at lowering peaks, or flattening a wide region.
 
CraigVMN said:
Go to partsexpress.com and search for bass blockers
Click to expand...
Thanks. The Harrison Labs Inline Crossover fmod look to be useful. These can be had for an inexpensive 25$ per pair. Unfortunately, the XLR versions are 70$ each, and aren't available at PartsExpress. Still, it may be the cheapest solution. Thanks
 
The 4
NeilBEN said:
I would suggest a miniDSP 2x4 ( https://www.minidsp.com/products/minidsp-in-a-box/minidsp-2x4 ) which lets you configure the 4 outputs - 2 with high pass for the speakers, and 2 with low pass for the subs. You can experiment with the crossover frequencies and slopes. This is single ended, so that is not helping get anything balanced.

I am using the 2x4 HD as an active crossover with my Linaeum LT1000, and it adds the ability to have custom EQ, which can correct frequencies that may be too high. It can pull up small drops in response; but is better at lowering peaks, or flattening a wide region.
Click to expand...
4X10 HD (500$) is balanced capable, although requires adaptation to from XLR to Phoenix connectors (not a deal breaker). How is miniDSP for introducing noise? Is my concern for analog sources going through conversion to digital and back again to analog overblown in my mind out of ignorance, and not possibly audible with artifacts, losses or mistakes?
 
If I'm not mistaken, your subs already have high-passed outputs. Have you tried using them?

IMO, it is definitely possible to over-think audio. ;)

Personally, I've never high-passed my mains. In my flavor of over-thinking, wave-front timing cues from full-range mains help with blending, and bass articulation. I would set the sub's low-pass crossover really low, like maybe 40 Hz, and run the mains full range. I would place the subs near the mains, and run them as a stereo pair, with each sub only getting input from one channel, left or right. Stereo bass is the cat's meow! :)
 
sooner8888 said:
I thought about miniDSP with XLR, but as I often do my critical listening though Schiit Sol turntable, it doesn't make since to me to convert analog to digital and then back to analog. Am I overthinking this solution, or overly concerned about degradation of the analog sound quality with all the signal conversions?
Click to expand...
One thing I tried with some success was a DSP solution, but one that does the analog-to-digital conversion only on the subwoofer signal, leaving the mains signal all-analog. The DSPeaker Anti-Mode 8033 unit only digitizes and room-corrects the sub's signal. It really does improve sub performance, especially in difficult (rectangular) and smaller rooms. I moved it on because my room is not difficult, and to do stereo bass, I would have needed to buy another. It has a microphone, and a self-calibrating routine for setup that worked pretty well, if you ran the calibration when the house is QUIET.
 
One 250uf cap in series with your mains, if you wanna go cheap just to check it out. This will be a gradual roll off. I would think the sub (as mentioned above) would have high pass out, which could be just passive caps.
I use an inexpensive Behinger CX3300 or something, I’m not at home, that works great the rare times I use it. I think I paid $75 at a pro audio store that sold used gear.
 
sqlsavior said:
I would set the sub's low-pass crossover really low, like maybe 40 Hz, and run the mains full range. I would place the subs near the mains, and run them as a stereo pair, with each sub only getting input from one channel, left or right. Stereo bass is the cat's meow! :)
Click to expand...
This is pretty much where I am currently...although subs are getting their respective channel signal starting around 60Hz.

I overthink it as why ask the LS50s to try to do bass while midrange too. They do the mids so well, why mess that up with bass frequencies too. I'm certainly no audio engineer or psychoacoustic expert, tho.
 
sqlsavior said:
If I'm not mistaken, your subs already have high-passed outputs. Have you tried using them?
Click to expand...
I did indeed. Only issue was that the subs are RCA only, and my pre is best with balanced XLR connections. I can't hear a difference in passive or tube buffered mode, but JFET mode is reduced. I use JFET for most of the casual listening, and tubes for the less frequent critical listening. I guess I could just move to passive for casual and background listening.
 
What genres of music do you listen to?

Because different people listen to different music, different people have different needs for a disc player. For classical music, Blu-ray audio/video, Ultra HD Blu-ray, Pure Audio Blu-ray, SACD, and hi-res (e.g., 24bit/192kHz, or DSD) downloads are indispensable.

The Oppo UDP-205 supports:
  • CD,
  • DVD,
  • DVD-Audio,
  • SACD,
  • Blu-ray,
  • Pure Audio Blu-ray,
  • Ultra HD Blu-ray, and
  • Hi-res downloads.
The Oppo universal players (e.g., UDP-205, BDP-105, BDP-95) feature "bass management" - i.e., a built-in configurable crossover, and an RCA connection for a powered subwoofer. With Oppo's bass management, the low frequencies are off-loaded from the main amp and speakers, thereby facilitating greater overall dynamics.

Analog audio connections are supported for 7.1 via the UDP-205’s built-in audiophile-grade DACs. Main L&R connections (i.e., stereo) are available as RCA connections, and XLR balanced connections.

The Oppo’s variable output can directly drive power amps, in addition to integrated amps and preamps. (An Oppo adds a remote volume control to vintage amps.) I drive vintage tube power amps with my UDP-205 (and BDP-105 and BDP-95) – i.e., no pre-amp or AVR. Stereo and multi-channel.

If you just need support for CDs, DVDs, and SACDs, the Oppo DV-980H will do the job and is readily available - cheap.

Of course, the Oppos don’t support LPs … which gets back to the question of genre of music.

In my living room system, I have an Oppo BDP-95 for playing Blu-ray, SACDs, CDs. and a USB hard drive containing high-res FLAC recordings. For LPs I have a Dual 1249 with Stanton 681EE equipped with a new Shibata stylus. For digital recordings the Oppo provides bass management and connects the subwoofer. For LPs, there is no crossover or subwoofer, which I think is OK because I have full range speakers, and I don’t think of LPs as having powerful bass compared to modern hi-res digital recordings. LPs playing through the main speakers provides a different (vintage) listening experience, vs. modern 5.1 hi-res recordings played via the Oppo and subwoofer.

For serious listening, I employ modern hi-res multi-channel classical recordings on Blu-ray, Pure Audio Blu-ray, and SACD, which blow away LPs and CDs in terms of audio quality. For me, LPs can be fun when guests want to hear them, but there is no comparison with Blu-ray’s DTS-HD MA 5.1 audio.
 
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sqlsavior said:
If I'm not mistaken, your subs already have high-passed outputs. Have you tried using them?

IMO, it is definitely possible to over-think audio. ;)

Personally, I've never high-passed my mains. In my flavor of over-thinking, wave-front timing cues from full-range mains help with blending, and bass articulation. I would set the sub's low-pass crossover really low, like maybe 40 Hz, and run the mains full range. I would place the subs near the mains, and run them as a stereo pair, with each sub only getting input from one channel, left or right. Stereo bass is the cat's meow! :)
Click to expand...

Excellent advice.
I run my Hales Signature Twos full range while using two stereo subwoofers and a central subwoofer.
Would hate to snuff out the GREAT, tight, fast bass the Hales provides down to about 45- 50Hz!
Plus a crossover puts another series of electronics in the signal path...
Set Up.JPG
 
TubeMon said:
Would hate to snuff out the GREAT, tight, fast bass the Hales provides down to about 45- 50Hz!
Click to expand...

In the OP's case his speakers I would say are less capable the lower frequency and likely indicate irregularities
on the way down hence his current questions.

Mid bass drivers are a common example.
 
sooner8888 said:
The 4

4X10 HD (500$) is balanced capable, although requires adaptation to from XLR to Phoenix connectors (not a deal breaker). How is miniDSP for introducing noise? Is my concern for analog sources going through conversion to digital and back again to analog overblown in my mind out of ignorance, and not possibly audible with artifacts, losses or mistakes?
Click to expand...

I was quite skeptical about the whole concept of an active crossover, but I am a convert. The killer feature is the custom EQ that you can get, using the miniDSP UMIK-1 (calibrated mic) and REW (Room EQ Wizard). You can do in a day or so, what an experienced speaker designer would take far longer to do, and I daresay the control you have on the speaker's output is much better.

You can do pretty precise phase matching with a sub (though I have not done this).

The miniDSP 2x4 HD is quieter than my system. I recently added diodes to the ground wire to my amps and the miniDSP, and it is a vast improvement (I had an intermittent ground loop hum), and I don't hear any noise now, for all intents and purposes.

The clarity and dynamics are better than any speaker that I have ever heard.
 
NeilBEN said:
I recently added diodes to the ground wire to my amps and the miniDSP, and it is a vast improvement (I had an intermittent ground loop hum), and I don't hear any noise now, for all intents and purposes.
Click to expand...
I'm curious about exactly how you did this. I'd like to try it myself.
 
sqlsavior said:
I'm curious about exactly how you did this. I'd like to try it myself.
Click to expand...
Sure - I read about someone tearing down a device that is sold to eliminate ground loop hums, and the working parts were simply two 400V 6A diodes that are connected together in opposite orientations i.e. the anode of each diode is connected to the cathode of the other. I am not sure of how this works, but it does.

The 6A pair is rated for 450 watts, I think, so i did 3 pairs of diodes - which is a bit of a pain to solder. It is more than enough to draw 15amps. I bought a quad outlet box, and wired the ground through the bundle of diodes. I plugged my two power amps and the miniDSP 2x4 HD into it. It is much quieter - but also the resolution of details, and the clarity of vocals, was a startling surprise.

I literally can easily make out the lyrics better, of every song I listened to. I was not expecting anything more than lower noise.
 
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