[TRE]

I have done quite a bit of research but am reading opinions all over the place on this. You guys know way more about these speakers than I do so I thought I would get some advice that comes with real life VMPS experience. I have the RM40s and two of the larger vertical subs, these are not the mega woofers and the internal crossovers were bypassed by the previous owner. What is a good starting point for the crossover setting? I am thinking 50-80 Hz ballpark. I know there are probably a lot of variables involved. These are being used for two channel music listening. I am planning to use the original passive crossovers in the RM40s for now since I am on a budget so I am thinking of just passing the frequencies above the sub crossover setting to them. I apologize if I am not speaking correctly I am new to this and trying to learn. If it helps I am using an Adcom GFP500 preamp and Adcom GFA555 amp for the RM40s and was planning to use a second GFA555 for the subs. I already have this preamp and the amps which is why I am going this way. I will probably upgrade in the future. Can you recommend a good budget oriented crossover (under $1000)? Thanks in advance and Happy New Year!

[FullRangeMan]

What is a good starting point for the crossover setting?
The best adjusting is what your ears like more.
I will decline to comment spend this plenty of money on ''budget'' xovers.

[Evoke]

I have done quite a bit of research but am reading opinions all over the place on this. You guys know way more about these speakers than I do so I thought I would get some advice that comes with real life VMPS experience. I have the RM40s and two of the larger vertical subs, these are not the mega woofers and the internal crossovers were bypassed by the previous owner. What is a good starting point for the crossover setting? I am thinking 50-80 Hz ballpark. I know there are probably a lot of variables involved. These are being used for two channel music listening. I am planning to use the original passive crossovers in the RM40s for now since I am on a budget so I am thinking of just passing the frequencies above the sub crossover setting to them. I apologize if I am not speaking correctly I am new to this and trying to learn. If it helps I am using an Adcom GFP500 preamp and Adcom GFA555 amp for the RM40s and was planning to use a second GFA555 for the subs. I already have this preamp and the amps which is why I am going this way. I will probably upgrade in the future. Can you recommend a good budget oriented crossover (under $1000)? Thanks in advance and Happy New Year!

Use an active crossover with an amp for the woofers, and an amp for the RM40's. If you have a pre-amp with sub out - use that and just run the subs as mono. The RM40's don't really need additional bass - they are pretty great "as is". So my guess is that you want to increase the "aural weight" of the bottom end. The sub out will do the trick and the LFE output can be increased for movies. DO NOT use a passive crossover. You will open a huge can of works that would be an extensive response.

[TRE]

You are correct that the RM40s have enough bass (I love them) but I am trying to increase the "feel" of the bass at lower listening levels, I assume that is what "aural weight" means? When the larger subs were auditioned that is what sold me on them. Any suggestions on a crossover? My preamp does not have a sub out and I do want to run the subs in stereo. Am I correct in believing that LFE combines the sub signals into mono? I have found a lot of crossovers that combine the sub into mono and have read a lot of thoughts on stereo VS. mono on subs and I guess I am trying to cover myself both ways by buying a stereo sub crossover. Thanks for your reply and for your patience with my ignorance.

[TRE]

What is a good starting point for the crossover setting?
The best adjusting is what your ears like more.
I will decline to comment spend this plenty of money on ''budget'' xovers.

I totally agree that what our ears like is the ultimate solution.

[ZAKski288]

Hello TRE, I would use the second GFA555, to bi-amp the RM40’s. Then buy a used Crown XLS 1500 amp or (XLS 2000) for your  subwoofers. In low pass mode you can adjust your crossover points to a number of Hz. This is the Amp I’m using (actually one amp per side) on my larger Subwoofers, I think I’m at 50hz on mine. Good luck Zak

[John Casler]

Hello TRE, I would pick up the second GFA555, but use it to bi-amp the RM40’s. Then buy a used Crown XLS 1500 amp or (XLS 2000) for your  subwoofers. In low pass mode you can adjust your crossover points to a number of Hz. This is the Amp I’m using (actually one amp per side) on my larger Subwoofers, I think I’m at 125Hz on mine. Good luck Zak

I have set up hundreds of VMPS systems and one of the biggest mistakes made, is having the subs produce too many frequencies produced by the RM-40s.

They generally go down to roughly 24Hz.  This means the LARGERS should be rolled in just "slightly" above that, at the highest 30Hz.

If you go higher than that, both the subs, and FR RM-40s will be producing the SAME frequencies from what ever you set (say 80) and the lower range of the RM-40.  This means that if the RM40 woofs are not in TOTAL exact sync (phase) as the Larger, then you bass will be muddy, and fuzzy.

Now this is for High End Audio.  If it is for HT, where you are not trying for the most realistic and perfect 2 channel sound then simply set it for what ever frequency floats your boat.

And the suggestion for the CROWN is also a GREAT ones since it has digital low pass setting for you.

Finally, I have used the CROWNS also to biamp the woofers on the RM40s and they are quite up to that task.

[poseidonsvoice]

John & Evoke,

I don’t understand all the guesswork in this era of room measurement software that is FREE. Why not resort to science? Does it take work? Yes. Effort? Yes. But the results are amazing. Is the ear the final arbiter? Yes. But it is of much lower resolution imho under 300Hz and can easily be fooled especially when problems lurk in the modal region and below.

Room EQ Wizard, a calibrated usb microphone, a boom mic stand, and a laptop is all one needs (outside of the laptop, that’s a $200 investment). 

This post has the details, and links whether one sub or multiple subs:
https://www.audiocircle.com/index.php?topic=155030.msg1659006#msg1659006

Happy New Year,
Anand.

[Evoke]

You are correct that the RM40s have enough bass (I love them) but I am trying to increase the "feel" of the bass at lower listening levels, I assume that is what "aural weight" means? When the larger subs were auditioned that is what sold me on them. Any suggestions on a crossover? My preamp does not have a sub out and I do want to run the subs in stereo. Am I correct in believing that LFE combines the sub signals into mono? I have found a lot of crossovers that combine the sub into mono and have read a lot of thoughts on stereo VS. mono on subs and I guess I am trying to cover myself both ways by buying a stereo sub crossover. Thanks for your reply and for your patience with my ignorance.

Exactly - the lower the frequency the more air you need to move. A 12" may go below 20 hz, but it won't move the air of multiple larger drivers.

[Evoke]

John & Evoke,

I don’t understand all the guesswork in this era of room measurement software that is FREE. Why not resort to science? Does it take work? Yes. Effort? Yes. But the results are amazing. Is the ear the final arbiter? Yes. But it is of much lower resolution imho under 300Hz and can easily be fooled especially when problems lurk in the modal region and below.

Room EQ Wizard, a calibrated usb microphone, a boom mic stand, and a laptop is all one needs (outside of the laptop, that’s a $200 investment). 

This post has the details, and links whether one sub or multiple subs:
https://www.audiocircle.com/index.php?topic=155030.msg1659006#msg1659006

Happy New Year,
Anand.

There is a lot of free software, some fairly good. And you are 100% right - between 200 and 500 hz is a nightmare for even the most experieneced professional.


That said, there are a number of assumptions we can make from lots of research etc. One is the crossover frequency of a subwoofer. We can state that 60 - 80 is a safe number so as not to affect the sound of the larger speaker. The MMS of a sub is terrible with relationship to a high performance woofer of a main speaker, typically.


From there, there are those with some basic tools can things right. Of my clients, less than half use technical tools for room tweaking. As a point, I have a number of portable devices to measure SPL, frequency response etc. -- Lot's of stuff under $500. They are great tools and really help get things rolling. When I do want to get into the nitty-gritty, yes, the laptop, a mic stand etc is the way to go. My one argument is the microphone used. I have a lab reference mic for measurements and it was about $1500. While from 500 - 10K is not too critical, below 500 is very important to have a good mic.

[YoungDave]

I think it is very important to not run the RM40's at full range while using a subwoofer.  In other words, let the subs get the frequencies below your desired crossover point (I recommend 50-70 Hz), and only send the frequencies above that selected crossover point to the RM40's.  That will avoid the muddied phase response in the bass that John Casler referred to. 

This approach does require a stereo electronic crossover as you indicated in your original post.  Certainly, a single stereo crossover that enables running the subs below 70Hz and the RM40's above 70 Hz will get you to a good starting point.  There are a good many inexpensive crossovers out there that can give you crossover point and slope selection and level adjustment - Behringer makes some, I think, and no doubt many members will have some suggestions along these lines. Many people will struggle with the finer points of crossover slope, but I think that adjusting levels and selecting a relatively steep slope at a useful frequency will get you where you want to go. 

Years ago, with my 2 Larger subs and 2 RM40's, I built and used a really fine crossover from White Noise Audio, David White, proprietor - an Audio Circle contributor at the time.  I regret that Dr. White left the business shortly thereafter.  I used his crossover for a couple years, eventually stripping all the passive crossovers from my speakers and quad-amping them (3 amps for the RM40's and 1 for the subs).  Yes, stereo for all, although truthfully the stereo image for the subs is not important. 

FWIW, I still use my 15-year-old RM40's and 2 Largers, but my White Noise crossover is in storage as I shifted over to DEQX speaker and room correction some years ago.  I am absolutely against passive crossovers ever since I first went the electronic crossover/triamp setup within 2 years of buying the RM-40's - I cannot foresee any circumstance that would lead me back to the one-box, one-amp type of setup.  It is not that the amp cannot manage the complexity of a full-range signal; it is that the passive crossover presents a crazy-quilt of frequency-dependent impedance loads that adds a lot of coloration and phase-incoherency to the sound.

[simon wagstaff]

DQX is a great suggestion, just as long as you dont mind the analogue>digital>analogue  conversion step. I don't know, I have never used one. I understand they are pretty transparent.

I use a Marantz AV 7702II as a pre-pro for both music and movies. Mainly music and i think it sounds very fine in stereo. I have the opposite issue. I picked up a pair of funky RM2s at a yard sale. They sound better than any speaker I have owned, especially in the detail and transparency in the 250>1000 hz range. Inner detail. For some reason the dont have much output below 100hz. Something is not right with them. The crossovers are set in glue. I have the woofers bypassing the bass crossovers, straight from the inputs to the speaker terminals. Its a long story but I am not messing with them anymore. Might help to replace the woofers, and there are other things I can do. I have a pair of smaller subs with 500 watt plate amps, they also have a crossover. I run the VMPS subs up to about 100hz and then, using the line level outs in the plate amps pass pass the signal to the woofers of the RM2s using an Adcom amp with a level control. I use the crossover in the Marantz pre-pro set at 250 hz into the plate amp. I think the crossover should be 280hz.

Pretty cludgy, but really works well with audessey. Best I have had, though not a wide soundstage. I was really an wide soundstage guy, but the depth and detail really make up for it. They are no Gallo Ref 3.5s, but I much more enjoy these funky, screwed up RM2s.

[TRE]

Thanks to everyone that responded, you have really given some great information. This definitely gives me some great ideas to pursue. A safe and happy New Year to all of you.