Active Crossovers, Subs, Maggies, etc.

[Mark Wayne]

I haven't done a thorough search here, but perhaps someone can point me in the right direction.

I'm buying some Magnepan .7s soon and am trying to figure out how to use either an active
crossover (maybe a mini dsp at some point but that seems to be a whole other issue).
What I'm looking for is a high pass filter so that I can remove the lower frequencies from the Maggies
(or perhaps a pair of bookshelf speakers that I have) and eventually run two subs.
If you have any experience with active crossovers, I'd appreciate any advice you have.
This is a bit confusing... I currently have a Rogue Audio Cronus Magnum II which is an integrated.
See: https://www.whathifi.com/rogue-audio/cronus-magnum-ii/review

Rogue Audio Cronus Magnum II review | What Hi-Fi?
Rogue Audio Cronus Magnum II review This valve amplifier is a fine alternative to transistor-based amps Tested at £2495 By What Hi-Fi? 15 August 2016
www.whathifi.com

I'm also considering buying something new at some point, such as the new PS Audio Strata, an integrated with a built in DAC, or maybe a Hegel H190 which also has a buit in DAC. See: https://www.psaudio.com/products/stellar-strata/#tab-rear-panel

Stellar Strata | PS Audio
The idea of combining a cutting edge DAC, full-featured analog preamplifier, high-definition streaming module, and a robust 200 watt per channel power amplifier was the basis of the Stellar Strata™ design imperative. We wanted an easy, simple, no-compromise musical experience whether streaming high-resolution audio from Tidal or Qobuz, exploring the millions of choices on Spotify, or ...
www.psaudio.com

I currently have a REL sub, but I think the ideal would be two Rhythmik FM8s because they play up to 250 Hz and I want to try to cross over relatively high... perhaps around 200 Hz (basically bottom of the female vocal range) with a sharp rolloff (18/24 db). See: https://www.rythmikaudio.com/FM8.html
Rythmik Audio servo subwoofer 8" FM8
The subwoofer for audiophiles with the need to play up to upper bass. For audiophiles looking for uncompromising accuracy in both bass and upper bass frequency range and higher crossover frequency up to 250hz, our F8 subwoofer is the ultimate choice.
www.rythmikaudio.com

The Rhythmiks are active and mention that they have a high pass out. The site says: FM8 uses two Hypex Ucd class D modules in the power amplifier with each module independently driving an 8" driver. Hypex Ucd modules are considered as one of the best sound quality class D modules available. The standard amplifer is HX585 (300WRMS x 2 for a total of 600WRMS), It has two RCA inputsand one highpass filter output.

So, if I understand correctly, does this mean I just feed the DAC into a pre section of my Rogue into the sub, and then high pass out to the power section of my Rogue and then out to the speakers? It's just not clear to me whether I can do this with the Rogue or maybe that PS Audio Strata in the future.

As far as active crossovers, the Bryston 10b-sub is available on the used market. Not "cheap", but I trust the Bryston name. See: https://6moons.com/audioreviews/bryston2/crossover.html There is also Marchand electronics XM-44. I'm not sure of the price though. I think there was a mention of needing to remove a jumper from the pre to power section of an integrated somewhere in an article about another possibility...

Anyway, this is all a little confusing. First step is to get the Maggies in December and hopefully sell the Klipsch, but I'm going to try to integrate a sub at some point and want to avoid making a purchasing error.

Any suggestions are welcome including any other forums where I might get some good feedback.

 

[JoeESP9]

Currently I use a DBX-223SX crossover set at ~65Hz to drive the amplifiers for my Maggie 1.7's and DIY TL subwoofers. Tubes on the Maggies and SS for the subs works for me. Although there are passive high and low pass filters available, IME an electronic crossover is a big improvement if for no other reason than its easily adjustable for levels and frequency.

Using a crossover frequency much higher than 100Hz with Maggies and Acoustat ESL's results in a discontinuous sound as easily heard on many Martin Logan hybrid ESL's.

A single sub or subs crossed over at 250Hz is simply to high a frequency. Once you start driving a subwoofer with signals higher than 100Hz or so the sub becomes an easily audible separate speaker. This is exactly what you don't want with any subwoofer.

IMO/E a 250Hz crossover between any panel speaker and a cone type woofer doesn't sound cohesive. The higher the crossover frequency the easier it is to hear the difference between dipolar sound (Maggies, ESL's) and a cone (sub). 100Hz is the highest I've ever gone. That was because the Acoustat Spectra 22's w/SPW-1 (bought new in 1989) have built in high and low pass filters.

As soon as I acquired an electronic crossover I started lowering the crossover point. ~65Hz has become my go to setting after lots of listening and tweaking.

Have you heard Maggies? I ask only because their sound is as different from Klipsch as you could possibly imagine. If you like the Klipsch sound it's highly probable you won't like Magnepans or ESL's.

I love the sound of ESL's and Magnepans. OTOH, I've never heard a Klipsch speaker that didn't make me want to cut of my ears and run away.

 

[Akustic]

Why do you want to cross over from a Maggie at 250hz ??

They're quite capable far below that, and it seems to me that you would lose the Maggies very quick and accurate lower end ..

They have the quickest, most accurate upper bass/lower midrange that I've ever owned
Seconded in my opinion by the best 8" acoustic suspension drivers but the cone driver is definitely second.

 

[twiiii]

M&K used to make delightful little sub with dual 8's that performed well down to 25 HZ. But if you want to reach lower you will need one with the dual 12's. They aren't cheap. but you can start out with one and select the frequency where you think your Maggies are beginning to be compromised. Then you can add an active crossover later. Rane use to make a nice active crossover with 24 db per octave slopes meaning their very are very few issues in one speaker influencing the other allowing for better combining in the very narrow crossover region. They are almost indestructible being made for professional application. AC 22 and AC 24 come to mind, but you will have to do your due diligence.

 

[ehoove]

I use a HNT X1 crossover with 2 NHT W2 Sealed subs with excellent results. Each has a 12 " woofer in a sealed enclosure. I drive them in Stereo with a Aragon 4004 MkII amplifier I cut off the MGIIIa's at 48Hz and run the subs up to 58 hz. The integration is seamless.
Regards,
Jim

 

[a_retent]

@Mark Wayne
I currently drive a pair of 1.6QRs bi-wired and full range from a pair of audio research vm220 tube monoblocks. To fill in the bottom freqs I use a pair of Carver knightshadow subs positioned behind each panel and powered by their onboard amps. Both subs are crossed over at 60-65Hz by way of a dbx 120x-ds subharmonic synthesizer at line level. This arrangement allows the 1.6s to roll off the bass naturally while the subs fill the fundamental information the maggies just aren't capable of doing (like down to 18Hz if necessary).
If I were to simplify the knightshadow and maggie connection I would run high level out (speaker wires from the amplifier output) to the high level input on the subs utilizing the sub's on board xover still crossing over at about 65Hz. Then send the crossed over high level output, located on each sub, off to the maggie's speaker wire connections.

I realize not all powered subs have high level input/output so this type of connection wouldn't be available in all instances. I highly recommend you review the connection instructions contained in the owner's manual for the sub you are looking to purchase to be certain the unit will work in your set up. I did see your CMll does have fixed and variable line level (RCA) output connections on the back of the unit. The variable connection (VAR) may be a point of connection for the active crossover which would raise and lower subwoofer volume at the same time main speaker volume is raised and lowered...again, refer to the owner's manuals of each unit to find out what those connections were designed to perform.

So much more information is available here on AK about bi-amped subwoofers and their integration into 2-ch audio systems. We the audience here cannot accurately tell you what to buy as we don't have your identical system set up in an identical acoustical environment listening with your ears. I cannot speak for the collective here but I can tell you after more than 40 years in this hobby I've made my fair share of bad moves but learned from each and every one. Sometimes trial-and-error is the way to find what you're looking for in this hobby.
Best of luck to you in your journey here.

 

[Blue Shadow]

does this mean I just feed the DAC into a pre section of my Rogue into the sub, and then high pass out to the power section of my Rogue and then out to the speakers?

DAC>>Rogue>>preamp output of Rogue>>sub>>high pass out of sub>>can't go to the Rogue based on no power amp input on the back panel that I saw. It appears there is a fixed output for a recording unit and a variable output to use the unit as a preamp.

The Strata does not appear to have power amp inputs and neither does the Hegel.

Without info on the current sub, I can't tell what the first step might be with the speaker swap. I have subs with line inputs and outputs and amplifiers to take this split signal and drive the magneplanars, sub keeping what it wants, preset high pass, though.

There is discussion of painting yourself into the box that you buy if you buy one with a built in DAC. A new DAC sure no problem but then you have that built in you paid for doing nothing a few years or less down the road.

You need separate amplification, independent of the preamp functions (preamp output power amp input could be enough) to use the preamp full range and the power amp for the top end of the rig with the sub keeping its parts. Whether the sub splits the signal or you use an electronic crossover or minidsp, you need a way to get a volume adjusted preamp signal into a power amp section of your gear.

A bit more discussion here would be good on this. But you asked for other options and maybe the planar forum at audio asylum would have some additional info.

Most seem to think that running Magneplanars as full range as possible and using the sub for the very bottom yields the best results. The .7 probably rolls off fairly high up compared to their larger speakers but anything over 80 might be to high. You don't want to hear the sub, you want to hear Magneplanars with a filled in bottom end.

 

[sqlsavior]

I currently have a REL sub, but I think the ideal would be two Rhythmik FM8s because they play up to 250 Hz and I want to try to cross over relatively high... perhaps around 200 Hz (basically bottom of the female vocal range) with a sharp rolloff (18/24 db).

Wrong approach, IMO. Cross over as low as the .7s will play, maybe 45 Hz.

 

[Mark Wayne]

Thanks to all who replied. Happy Thanksgiving everyone. I will need some time to digest this but you have already been a big help. Be back next week to respond...