Monolith3 Replacement Woofers

MartinLogan Audio Owners Forum

Help Support MartinLogan Audio Owners Forum:

mikebecerr1258

Active member
Joined
Jun 1, 2022
Messages
31
Reaction score
1
Location
Parma, OH
Yeah, that's worrying, I scanned DIYaudio, and others are reporting the same.
Must be a one-person show and they are either not responsive enough or have moved on.

Mike, I'd proceed with caution, only order once you'd established contact. And possibly, time to look for alternatives (Marchand is always one).
Jonathan... I haven't been able to contact Sublime either. I sent an e-mail several days ago with no response. So... armed with one of those 4 Preamps, and Two Class-D Gan 350 wpch Amplifiers, and One Polk Powered Sub-woofer... I would require a 3-Way XO (NOT a 2-way?) which COULD be either the Marchand XM44 OR the DBX Driverack Venu 360??? And if that's true, then it appears the DBX is not only cheaper ($1100 as opposed to $1400), but also offers a whole lot more in terms of features???
 

JonFo

Super Moderator
Staff member
Moderator
Joined
Jan 16, 2005
Messages
4,675
Reaction score
402
Location
Big Canoe, GA
Class-D Gan 350
That LSA GaN being discussed in this thread? LSA Voyager GaN 350 Teardown (Class D Amp)

First, I'd worry about a class D amp (especially one with bridged amps, like the modules in that one are, dealing with the raw panel. Also, it seems to have very poor value.
At that price, I'd encourage you to hunt for a used Sanders (rare as hens teeth because no one ever wants to sell theirs) or a used Coda 200wpc (or better). Coda are the OEMs for Sanders amps.

Also, no point in wasting good money on a fancy amp for the woofers, any run-of-the-mill class A/B or Class D amp will do. If part of an all balanced setup, then any number of affordable (<$700) Pro audio amps would work.
 

JonFo

Super Moderator
Staff member
Moderator
Joined
Jan 16, 2005
Messages
4,675
Reaction score
402
Location
Big Canoe, GA
I would require a 3-Way XO (NOT a 2-way?) which COULD be either the Marchand XM44 OR the DBX Driverack Venu 360??? And if that's true, then it appears the DBX is not only cheaper ($1100 as opposed to $1400), but also offers a whole lot more in terms of features???
Correct, you need an XO capable of a three-way split.

The DBX is my favorite, thanks to the flexibility and way more features, but it comes at the cost of setup complexity. Once configured, it is plug-and-play. But if anyone ever messes with settings (loading a different preset, etc.) then you need enough tech-savvy to know how to identify and recover from that.

The Marchand makes sense for a pure unbalanced (consumer audio using RCA connections) system with very low tech demands, as aside from gain levels for each output, not much to adjust on those.
 

mikebecerr1258

Active member
Joined
Jun 1, 2022
Messages
31
Reaction score
1
Location
Parma, OH
Correct, you need an XO capable of a three-way split.

The DBX is my favorite, thanks to the flexibility and way more features, but it comes at the cost of setup complexity. Once configured, it is plug-and-play. But if anyone ever messes with settings (loading a different preset, etc.) then you need enough tech-savvy to know how to identify and recover from that.

The Marchand makes sense for a pure unbalanced (consumer audio using RCA connections) system with very low tech demands, as aside from gain levels for each output, not much to adjust on those.

Correct, you need an XO capable of a three-way split.

The DBX is my favorite, thanks to the flexibility and way more features, but it comes at the cost of setup complexity. Once configured, it is plug-and-play. But if anyone ever messes with settings (loading a different preset, etc.) then you need enough tech-savvy to know how to identify and recover from that.

The Marchand makes sense for a pure unbalanced (consumer audio using RCA connections) system with very low tech demands, as aside from gain levels for each output, not much to adjust on those.
Jon... I finally received a response from Mark Longley @ Sublime Acoustics!!! He has a 2-3 week back log at this time and I am going to order the K231 Stereo 3-Way Active Crossover from his company momentarily... but first... I need your answer to a very important discrepancy! In a past post/thread, you recommended these frequencies for the active XO: Sub xo @ 80 Hz/24dB Slope & Mid/High xo @ 300 Hz/24 dB Slope for the Monolith3's. HOWEVER, Mark @ Sublime Acoustics recommends: Sub xo @ 50 Hz/24dB Slope & Mid/High xo @ 120 Hz/24 dB Slope. I have no idea of Mark's actual reasoning, but this is HIS crossover. I also know you have a very extensive background/history with these speakers and putting them through various testing. Therefore, whose opinion should I accept? Or should I simply order the XO unit with 4 frequency modules (it comes from the factory with 2) to cover all four frequency recommendations (50, 80, 120, & 300 Hz/24dB Slope) and experiment with them??? Thanks!
 

JonFo

Super Moderator
Staff member
Moderator
Joined
Jan 16, 2005
Messages
4,675
Reaction score
402
Location
Big Canoe, GA
Jon... I finally received a response from Mark Longley @ Sublime Acoustics!!! He has a 2-3 week back log at this time and I am going to order the K231 Stereo 3-Way Active Crossover from his company momentarily... but first... I need your answer to a very important discrepancy! In a past post/thread, you recommended these frequencies for the active XO: Sub xo @ 80 Hz/24dB Slope & Mid/High xo @ 300 Hz/24 dB Slope for the Monolith3's. HOWEVER, Mark @ Sublime Acoustics recommends: Sub xo @ 50 Hz/24dB Slope & Mid/High xo @ 120 Hz/24 dB Slope. I have no idea of Mark's actual reasoning, but this is HIS crossover. I also know you have a very extensive background/history with these speakers and putting them through various testing. Therefore, whose opinion should I accept? Or should I simply order the XO unit with 4 frequency modules (it comes from the factory with 2) to cover all four frequency recommendations (50, 80, 120, & 300 Hz/24dB Slope) and experiment with them??? Thanks!
Hi Mike, good to hear you two hooked up and that you can source a unit.

As for why I think Mark suggests his XO points is that he went and read the specs for a stock Monolith III :)

However, the measurements I've made on the bare Monolith panel showed that 120Hz is too low an XO point, as it was already several dB down relative to 300Hz. And since an XO is not a brick wall but a slope, you are asking the panel to still put out some serious sound at 80 to 90Hz, even with a 24dB slope.

One of the reasons I go with the higher XO point to the panel is to move it out of the worst of the dipole cancelation range. At 120Hz, there is significant cancelation from the rear wave on top of the already diminished output. So why bother pushing the panel when the output at the listening position will be down relative to the upper regions?
If the unit were to be converted to monopole operation (which I eventually plan to do to mine), then for sure, I would test at lower XO points but still above the output drop-off point.

The other reason for the 300Hz XO point is the power curve. At 75 or 85dB, sure the panel might have decent output below 300Hz, but at 100dB+, no way. Panel resonances build up and THD goes well over 1%.
So to have a consistent power curve (same frequency response at varying output levels), keeping the panel at 300Hz and above is what works best, at least per measurements and my experience.

This brings us to the recommendations for XO points.

I'll stick with my 300Hz @24dB/Octave for the panel high-pass.

The woofer to sub should be a bit higher than Mark recommends, as ESLs are typically placed in locations (multiple feet away from walls) that are not conducive to great low-end in-room output.
So I'd say 60Hz is the lowest I'd go, and 70 or 80Hz might be better. But some measurements of the current units in the locations you have them now might reveal room modes you might want to avoid. So if the current placement has a big null @70Hz at the ML (with no sub), then you definitely want to go higher than 80Hz for the XO to the sub.

So if you do not have a big null @70Hz, then I'd use that for the low-pass to the sub, high pass for the woofer.
Low pass for the woofer would be the same 300Hz as the HP for the panel.

Cheers.
 

mikebecerr1258

Active member
Joined
Jun 1, 2022
Messages
31
Reaction score
1
Location
Parma, OH
And it is important to do so, as we'll see:

Halo P6 - Sub out is from a true crossover, with the main pre-out being affected as well.

Rotel RC-1572 Neither the marketing blurbs nor the owner's manual indicate if the sub-out has any crossover, nor the frequency or slope. So the conclusion is that it is just an L/R sum of the primary signal, and the main pre-out is never affected. Wierd for an otherwise nice piece of kit clearly designed in the past few years. On the plus side, it has MQA, and is a Roon-ready target (both require software on a PC to manage the tunes, but it can be as simple as the Tidal App).

NAD C165BEE Same problem as the Rotel, it's a summed L/R, but at least here, it is low-passed at (guessing) 80Hz as the spec is -3dB @ 100Hz. The main pre-out does not seem to be affected. So pass on this for 2.1 as well.

Schiit Freya + Nice little Tube Pre-amp, but it is strictly a 2Ch preamp, no subwoofer integration at all.


So the only preamp in the list above that has an actual usable 2.1 implementation with legit low-pass, high-pass crossover for a sub is the P6.
Hello again JonFo... Keeping in mind that I have ordered the Sublime Acoustics K231 3-Way Active Crossover for my stereo 2.1 system... and I am integrating either 1 or 2 Powered Sub-woofers into this same system. So with the 4 choices of preamps listed above, would the Parasound Halo P6 still be the only true choice to make for this system? And if that's true, I really need to get your feedback on the Rotel RSP-1582 Surround Sound Processor!!! It appears that I can also use this as my Preamp, no? And if so, I can purchase it used for the same price as a used Halo P6!!! So my question is... will it perform in my system even better than the Halo P6 and would you highly recommend it???
 

JonFo

Super Moderator
Staff member
Moderator
Joined
Jan 16, 2005
Messages
4,675
Reaction score
402
Location
Big Canoe, GA
your feedback on the Rotel RSP-1582 Surround Sound Processor
If you can get that for the same or less as a P6, then jump on it.

That is a much more capable preamp, and will allow time-aligning the subwoofer output. This is a big deal and leads to better integration of the low-end.

It also has the option to configure a 10-band Parametric EQ, so you can further fine-tune the results in the room.

With a nice big usable display, this is a sweet preamp. With HDMI inputs, you can play high-res music from Apple Music, Tidal, etc. from an AppleTV4K.

So yes, recommended.
 

mikebecerr1258

Active member
Joined
Jun 1, 2022
Messages
31
Reaction score
1
Location
Parma, OH
If you can get that for the same or less as a P6, then jump on it.

That is a much more capable preamp, and will allow time-aligning the subwoofer output. This is a big deal and leads to better integration of the low-end.

It also has the option to configure a 10-band Parametric EQ, so you can further fine-tune the results in the room.

With a nice big usable display, this is a sweet preamp. With HDMI inputs, you can play high-res music from Apple Music, Tidal, etc. from an AppleTV4K.

So yes, recommended.
Thanks for your input! I went ahead and ordered the Rotel. Will give you feedback at a later date. Last question, while I am waiting for the Sublime K231 XO to arrive... Do I need ONE or TWO of these units for my 2.1/2.2 stereo system to work properly???
 

JonFo

Super Moderator
Staff member
Moderator
Joined
Jan 16, 2005
Messages
4,675
Reaction score
402
Location
Big Canoe, GA
Do I need ONE or TWO of these units for my 2.1/2.2 stereo system to work properly???

You only need one crossover box, as it is a stereo device.

However, now that you have a preamp with a built-in subwoofer crossover (a significant advantage, as it can be time-aligned relative to the mains), your crossover needs have changed.

The K231 only needs to handle a high pass for the ESL, and a low pass for the woofer.

Just ask the vendor for modules that make it a 2-way.

So the signal path in this configuration is:

Code:
Source ---> Rotel Preamp
             Subwoofer low-pass  ---> Subwoofer LFE input
             High-pass L/R out
                |     |
                |     |
          K231 2-way crossover
            |   |     |    |
           Low High
            |   |
        ----     ----
        |            |
    Woofer Amp    ESL Amp
        |            |
     Woofer         ESL

The Rotel sub out is an XLR, making it a better match for longer runs to the LFE input of the sub. So plan to cable appropriately; I recommend Blue Jeans Cable XLR (I have dozens in my rig).
 

Brandon Hartwick

Well-known member
MLO Supporter
Joined
Mar 17, 2022
Messages
186
Reaction score
111
Look at the Dayton 4X8 DSP unit for an easier, more affordable option. You can set it up easily with a laptop from your couch.
 

JonFo

Super Moderator
Staff member
Moderator
Joined
Jan 16, 2005
Messages
4,675
Reaction score
402
Location
Big Canoe, GA
Look at the Dayton 4X8 DSP unit for an easier, more affordable option. You can set it up easily with a laptop from your couch.
That's a nice unit, but this member has explicitly turned down any DSP or computer-managed units, as tech skills are lacking. So a pure analog unit with simple level knobs will do.
The preamp he's getting has a 10-band parametric EQ and will time-align the sub, so the major bases are covered.
 

Brandon Hartwick

Well-known member
MLO Supporter
Joined
Mar 17, 2022
Messages
186
Reaction score
111
That's a nice unit, but this member has explicitly turned down any DSP or computer-managed units, as tech skills are lacking. So a pure analog unit with simple level knobs will do.
The preamp he's getting has a 10-band parametric EQ and will time-align the sub, so the major bases are covered.
I missed that, admittedly I didn't read every comment.

Carry on lol
 

mikebecerr1258

Active member
Joined
Jun 1, 2022
Messages
31
Reaction score
1
Location
Parma, OH
You only need one crossover box, as it is a stereo device.

However, now that you have a preamp with a built-in subwoofer crossover (a significant advantage, as it can be time-aligned relative to the mains), your crossover needs have changed.

The K231 only needs to handle a high pass for the ESL, and a low pass for the woofer.

Just ask the vendor for modules that make it a 2-way.

So the signal path in this configuration is:

Code:
Source ---> Rotel Preamp
             Subwoofer low-pass  ---> Subwoofer LFE input
             High-pass L/R out
                |     |
                |     |
          K231 2-way crossover
            |   |     |    |
           Low High
            |   |
        ----     ----
        |            |
    Woofer Amp    ESL Amp
        |            |
     Woofer         ESL

The Rotel sub out is an XLR, making it a better match for longer runs to the LFE input of the sub. So plan to cable appropriately; I recommend Blue Jeans Cable XLR (I have dozens in my rig).
Hello Jonathan!!! I have 3 final questions to ask of you regarding this super-long thread. Initially, let me confirm the arrival of both the Rotel RSP-1582 Preamp/Processor AND the Sublime Acoustics K231 3-Way Active Crossover... although I can't comment yet on them due to the fact they have yet to be integrated into my 2.2 Stereo system! Firstly, the Rotel has only ONE set of out RCA jacks for the FRONT L & R Speakers. Since I am either Bi or Tri-Amping the ML MonolithIII's (along with my TWO SVS SB-2000 Powered Sub-Woofers)... How do I attach TWO sets of stereo RCA cables to run from the Rotel into the K231 XO??? I only have that one set of Front speaker out jacks, yet need to run cables to both the High and Mid RCA jacks on the K231. Secondly, Should I run the Sub Out 1 & 2 RCA outs on the Rotel to the K231 first, and then out to the SB-2000's with a 80Hz crossover setting, OR should I run the cables directly from the Rotel to the SB-2000's, and thus bypass the K231 altogether (for sub-woofer connection only)??? Thirdly, what type of cables/connectors should I use for these connections - I need one type going from the Rotel to the K231 High & Mid (could I use the SVS GOLD RCA Y Adaptor connector or some sort of RCA Y-Cable???). Would such an option result in some type of signal loss... and would it be significant or noticeable? And if I did decide to use the XLR/TRS connections on the 3 components... do they make, and do you recommend, a cable with an XLR/TRS connector at one end, and an RCA connector on the other? Does that even make sense? As always, can't wait for your response!
 

mikebecerr1258

Active member
Joined
Jun 1, 2022
Messages
31
Reaction score
1
Location
Parma, OH
Hello Jonathan!!! I have 3 final questions to ask of you regarding this super-long thread. Initially, let me confirm the arrival of both the Rotel RSP-1582 Preamp/Processor AND the Sublime Acoustics K231 3-Way Active Crossover... although I can't comment yet on them due to the fact they have yet to be integrated into my 2.2 Stereo system! Firstly, the Rotel has only ONE set of out RCA jacks for the FRONT L & R Speakers. Since I am either Bi or Tri-Amping the ML MonolithIII's (along with my TWO SVS SB-2000 Powered Sub-Woofers)... How do I attach TWO sets of stereo RCA cables to run from the Rotel into the K231 XO??? I only have that one set of Front speaker out jacks, yet need to run cables to both the High and Mid RCA jacks on the K231. Secondly, Should I run the Sub Out 1 & 2 RCA outs on the Rotel to the K231 first, and then out to the SB-2000's with a 80Hz crossover setting, OR should I run the cables directly from the Rotel to the SB-2000's, and thus bypass the K231 altogether (for sub-woofer connection only)??? Thirdly, what type of cables/connectors should I use for these connections - I need one type going from the Rotel to the K231 High & Mid (could I use the SVS GOLD RCA Y Adaptor connector or some sort of RCA Y-Cable???). Would such an option result in some type of signal loss... and would it be significant or noticeable? And if I did decide to use the XLR/TRS connections on the 3 components... do they make, and do you recommend, a cable with an XLR/TRS connector at one end, and an RCA connector on the other? Does that even make sense? As always, can't wait for your response!
 

JonFo

Super Moderator
Staff member
Moderator
Joined
Jan 16, 2005
Messages
4,675
Reaction score
402
Location
Big Canoe, GA
... confirm the arrival of both the Rotel RSP-1582 Preamp/Processor AND the Sublime Acoustics K231 3-Way Active Crossover... although I can't comment yet on them due to the fact they have yet to be integrated into my 2.2 Stereo system! Firstly, the Rotel has only ONE set of out RCA jacks for the FRONT L & R Speakers. Since I am either Bi or Tri-Amping the ML MonolithIII's (along with my TWO SVS SB-2000 Powered Sub-Woofers)... How do I attach TWO sets of stereo RCA cables to run from the Rotel into the K231 XO??

First, good to hear they have arrived.

The L/R signal from the Rotel preamp is just a single pair of RCA cables, per my diagram above.
Those will connect to the L/R input of the K231. So you only need what is already there.

Secondly, Should I run the Sub Out 1 & 2 RCA outs on the Rotel to the K231 first, and then out to the SB-2000's with a 80Hz crossover setting, OR should I run the cables directly from the Rotel to the SB-2000's, and thus bypass the K231 altogether (for sub-woofer connection only)???
The K231 will not be involved with the subs in any way, given that the Rotel has a much superior solution for that channel.

Ideally, you would use XLR cables from the Sub1 and Sub2 XLR outputs of the Rotel to the XLR LFE inputs on the subs. But you could use the RCA Sub1 and Sub2 outputs to the RCA LFE inputs on the subs. If purchasing new cables, get the BlueJeans XLR I previously linked to.


Thirdly, what type of cables/connectors should I use for these connections - I need one type going from the Rotel to the K231 High & Mid (could I use the SVS GOLD RCA Y Adaptor connector or some sort of RCA Y-Cable???). Would such an option result in some type of signal loss... and would it be significant or noticeable?

The Rotel L/R ouptut to K231 L/R input is via two RCA interconnects.

The Rotel Sub1/Sub2 to the subs is ideally XLR, as just mentioned in this reply.

You will need two more RCA interconnects to go from the L/R High output of the K231 to the amp L/R input that drives the panels.

Finally, you will need two more RCA interconnects to go from the L/R Mid output of the K231 to the amp L/R input that drives the woofers.

The sub outputs of the K231 are not used in this configuration, as the Rotel is already performing that crossover.
 

JonFo

Super Moderator
Staff member
Moderator
Joined
Jan 16, 2005
Messages
4,675
Reaction score
402
Location
Big Canoe, GA
And if I did decide to use the XLR/TRS connections on the 3 components... do they make, and do you recommend, a cable with an XLR/TRS connector at one end, and an RCA connector on the other? Does that even make sense?
I forgot to address this in my prior response, but best not to mix balanced, unbalanced connections if both ends can be kept consistent.

In your case, use RCA's for the L/R as that's the type of connection on the K231. And I recommend using the XLR to XLR if your subs have an XLR LFE Input, as the XLR cable is better at rejecting interference on long runs.
 

mikebecerr1258

Active member
Joined
Jun 1, 2022
Messages
31
Reaction score
1
Location
Parma, OH
Okay... I am going to run ALL unbalanced RCA connections for the 3 frequency ranges - Going from the Rotel L/R to the K231... and then out from the K231 High to the amp that powers the Panels, and out from the K231 Mid to the amp that powers the Woofers (which means the existing Monolith woofers have now effectively become the Midrange speakers). Lastly, going from the Rotel Sub1 / Sub2 directly to (thus bypassing the K231) the LFE on Each SB-2000 Sub. Note: The High/Mid XO will occur at 300Hz and then the Bass/Sub XO will occur at 80Hz per the K231.
Am I understanding all of this correctly?

Per the Sublime Acoustics website, there is access to the K231 User Manual online. On Page 4 (near the top), there is a paragraph titled "3-Way or 2-Way Active Crossover Configuration". The directions therein appear to be in disagreement with both your and my thoughts regarding how to connect the unit up properly. Can you please review and determine if it should be set up as a 2-Way (via mode switch) OR as a 3-Way? And as you can see, our thoughts as to how to run it as a 3-Way are to leave the Sub channel disconnected, whereas Sublime says if run as a 2-Way then to leave the High channel disconnected. I am totally confused... and hopeful you understand exactly what steps to take to configure properly!

Final note: Unfortunately, the K231 has only Balanced TRS jacks (not XLR) or Unbalanced RCA... and the SVS PB-2000 subs only have LFE RCA jacks (not XLR). Thus my reasoning to hook up everything via RCA's.
 

JonFo

Super Moderator
Staff member
Moderator
Joined
Jan 16, 2005
Messages
4,675
Reaction score
402
Location
Big Canoe, GA
Per the Sublime Acoustics website, there is access to the K231 User Manual online. On Page 4 (near the top), there is a paragraph titled "3-Way or 2-Way Active Crossover Configuration". The directions therein appear to be in disagreement with both your and my thoughts regarding how to connect the unit up properly. Can you please review and determine if it should be set up as a 2-Way (via mode switch) OR as a 3-Way? And as you can see, our thoughts as to how to run it as a 3-Way are to leave the Sub channel disconnected, whereas Sublime says if run as a 2-Way then to leave the High channel disconnected. I am totally confused... and hopeful you understand exactly what steps to take to configure properly!

Since when this whole thing started, the preamps you contemplated did not have sub outs or the level of sophistication the Rotel has, the thought was to place all crossover duties in the K231, so that's how you ordered it.
But now that the Rotel is here, the configuration on the K231 is a bit overkill, as all you need is a two way.
Since the modules and options are likely loaded up for 3-way operation, my latest instructions are to essentially use 2/3rds of the units I/O, basically, using it as a 2-way.

Functionally, that's fine, and you should wire it per my note yesterday with no changes to the K231 settings other than setting the levels.

Final note: Unfortunately, the K231 has only Balanced TRS jacks (not XLR) or Unbalanced RCA... and the SVS PB-2000 subs only have LFE RCA jacks (not XLR). Thus my reasoning to hook up everything via RCA's.
Understood, that sub model is RCA inputs only, make sure you use the one marked LFE and set the setting to use LFE mode.
 
Top