[ka7niq]

I am having a hard time in my room getting adequate bass out of my RM 40's.
As a result, I have to really turn my ribbon panels down.
I have tried several powerful amps on my speakers, and played with the putty a lot.

My speakers were purchased used, and so I started over with new putty.
I finally found some rope caulk, and measured a 8 inch long strand as I read to do in another thread.

I added that after I removed all the old putty, and tuned.

But I just can't seem to get enough bass drive to match the ribbons.

I am using only 14 guage wire, 12 feet on one side, and 15 feet on the other.

My friend Mike who also has RM 40 suggested I get some additional wire to combine with the 14 guage, and I am going to do as he suggests.

He says his 40's bass goes away unless he has big wire on the woofers.'

Anyone else ever experienced this ?

[pjchappy]

Maybe you have a room mode, or whatever, that's doing that?

[Brian Cheney]

The first generation 40's (which you have) with the spirals had a lean tonal balance.  In a small room the reinforcement from the three main modes, particularly 71hz/8 ft ceiling, filled in.  Your larger room lacks such reinforcement, normally a good thing.  But it makes the speakers sound thin.

Solution:  Add a sub.

[ka7niq]

The first generation 40's (which you have) with the spirals had a lean tonal balance.  In a small room the reinforcement from the three main modes, particularly 71hz/8 ft ceiling, filled in.  Your larger room lacks such reinforcement, normally a good thing.  But it makes the speakers sound thin.

Solution:  Add a sub.

So, the newer 40's are warmer sounding, is this because of the raised crossover point ?

Or, a  combo of things ?

[Brian Cheney]

The new, stronger midbass 10" plus the waveguide bring up the bass nicely on the new models.

[John Casler]

I am having a hard time in my room getting adequate bass out of my RM 40's.
As a result, I have to really turn my ribbon panels down.
I have tried several powerful amps on my speakers, and played with the putty a lot.

My speakers were purchased used, and so I started over with new putty.
I finally found some rope caulk, and measured a 8 inch long strand as I read to do in another thread.

I added that after I removed all the old putty, and tuned.

But I just can't seem to get enough bass drive to match the ribbons.

I am using only 14 guage wire, 12 feet on one side, and 15 feet on the other.

My friend Mike who also has RM 40 suggested I get some additional wire to combine with the 14 guage, and I am going to do as he suggests.

He says his 40's bass goes away unless he has big wire on the woofers.'

Anyone else ever experienced this ?

Couple things to try:

1) Move the speakers closer to room boundaries, which will reinforce low and midbass

2) Check that all woofers are "in phase" with a 9 volt battery (see if they both move "in and out" at the same time

3) Press gently on each woofer and the PR, to see if the system is "well sealed" and pressing in causes the other driver and PR to move out.

4) Move your listening positions forward and backwards a few inches at a time to see if you are seated in a bass node

5) Try the Sonic Director "tweak" (do a search for Sonic Director) posted some time ago on this site.

6) Remove PR and perform the Elmer's Glue Vitrification, if it has not already been done

7) Upgrade to the new "midwoofer".

Separate amp (bi-amp) Woofers

9) if single amp/wire plug into woofer (upper) binding posts first

10) Try your friends suggestion and run a "double run" to the woofers.

Just a couple things to try.

[ka7niq]

The new, stronger midbass 10" plus the waveguide bring up the bass nicely on the new models.

My RM 40's sound great, as is, but one is always looking for improvements.
Are the waveguides ready for the older spiral RM 40's yet ?
I realize I need to do something to the crossovers as well to correct for waveguide use.
I am not scared of going inside my speakers, and I can follow instructions.

For anyone who might be reading this thread, I am in a very large room, and the only place I can put my speakers is almost a "bass hole".

I do not want anyone to think that the VMPS RM 40's, even the older ones that I own, are a "deficient" speaker in any way.

My son has Cerwin Vega CLSC 215's with two 15 inch woofers in large cabinets.

They will almost break windows at his house.
In my room, they too need a subwoofer, even with all that cone area.

I am going to try some bigger wire on the woofers ?
What the heck ?

Marty De Woulff in his excellent review of the old RM 40's in Bound For Sound said he too had excellent results with really large wire size.

My friend Mike also owns the same older RM 40's as I do and swears by the bigger gage wire, so what the heck ?

[Brian Cheney]

RM 40 waveguides are $400pr plus shipping and include the xover updates.
New midbass 10" are $95ea and are needed with the CDWG.

[ka7niq]

I am having a hard time in my room getting adequate bass out of my RM 40's.
As a result, I have to really turn my ribbon panels down.
I have tried several powerful amps on my speakers, and played with the putty a lot.

My speakers were purchased used, and so I started over with new putty.
I finally found some rope caulk, and measured a 8 inch long strand as I read to do in another thread.

I added that after I removed all the old putty, and tuned.

But I just can't seem to get enough bass drive to match the ribbons.

I am using only 14 guage wire, 12 feet on one side, and 15 feet on the other.

My friend Mike who also has RM 40 suggested I get some additional wire to combine with the 14 guage, and I am going to do as he suggests.

He says his 40's bass goes away unless he has big wire on the woofers.'

Anyone else ever experienced this ?

Couple things to try:

1) Move the speakers closer to room boundaries, which will reinforce low and midbass

2) Check that all woofers are "in phase" with a 9 volt battery (see if they both move "in and out" at the same time

3) Press gently on each woofer and the PR, to see if the system is "well sealed" and pressing in causes the other driver and PR to move out.

4) Move your listening positions forward and backwards a few inches at a time to see if you are seated in a bass node

5) Try the Sonic Director "tweak" (do a search for Sonic Director) posted some time ago on this site.

6) Remove PR and perform the Elmer's Glue Vitrification, if it has not already been done

7) Upgrade to the new "midwoofer".

Separate amp (bi-amp) Woofers

9) if single amp/wire plug into woofer (upper) binding posts first

10) Try your friends suggestion and run a "double run" to the woofers.

Just a couple things to try.

Thanks John!

I will try your suggestions!

I wanted to upgrade to the new mid woofer, but Brian suggested I wait until waveguides were ready for the older RM 40's and do it all at once.

The nice thing is that my friend Mike also owns the same speakers as I do, and we are practically neighbors!

We can both upgrade our speakers together, and assist each other.

He might be a "harder sell" on the upgrade path then me, LOL

I think his RM 40's like his room better, my room is a difficult one.

The RM 40's have sounded the best of any speaker I have tried in here, but like all audiophiles, I am always looking to improve.

[fredgarvin]

Hi Chris, I see you got your Moscode back! I do not have 40's but I had the old rm1's and now have the new 626's with the new woofer and higher xo point. They definately sound better in the midbass IMO. If nothing else I bet a new megawoof with xo will really help, and no doubt the cdwg.

[audiochef]

ka7niq,
there has been significant upgrades since the original spiral versions . All ,I think in what your looking for.
New mid bass , cut off is 280 hz from 166hz. Your mids now are essentially big tweaters,they go up to 10,000hz.New cut off is at 6900hz. I've lined the mid  chamber with foam in addition to lambs wool which very noticeably added fullness and warmth. finally,it will be awfully awfully sweet with the addition of the new G3 tweater which you have room for.

Dream on. Stan

[ka7niq]

ka7niq,
there has been significant upgrades since the original spiral versions . All ,I think in what your looking for.
New mid bass , cut off is 280 hz from 166hz. Your mids now are essentially big tweaters,they go up to 10,000hz.New cut off is at 6900hz. I've lined the mid  chamber with foam in addition to lambs wool which very noticeably added fullness and warmth. finally,it will be awfully awfully sweet with the addition of the new G3 tweater which you have room for.

Dream on. Stan

I haven't been inside my speakers, YET.

But what you say concerning the damping of the midrange ribbons intrigues me!

No speaker is perfect, and sometimes compromises between fullness and low coloration  have to be made.

I wonder, since I am in a larger room that has no "fill in" from room nodes IF my ribbons would benefit from remeving some damping behind them.

They do sound "overdamped" a bit, since I have no room nodes to fill in the lower mids.

My Von Schweikerts midranges were overdamped, since Albert tuned them for a much smaller room.

Just the removal of about 1/4 of the damping material really warmed them up, like night and day!

I did detect just a bit of coloration, but it was far preferrable to me then the flip side, low coloration, and a thin, shouty, lifeless sound.

I find it interesting that you ADDED damping material, instead of reducing it.

Usually, more damping lowers Q, reduces coloration, but at the expense of Q.

The higher the Q, usually the warmer the sound, I thought.

[audiochef]

Yes , I don't understand these things from an engineering stand point as well at all. I'm a mechanical tweaker/ tuner and  though not everyone finds these changes to their liking, the improvements are tried and true , like Sonic barrier, cabinet bracing and lambs wool. Wool is $20.00 per lb at Maddisound, you'll need 2 . They have the foam as well.
 And one very important mod that  may not have been performed on your version is the mid panel rebuild thats done at the factory. Check with Brian on this.

Stan

[ka7niq]

Yes , I don't understand these things from an engineering stand point as well at all. I'm a mechanical tweaker/ tuner and  though not everyone finds these changes to their liking, the improvements are tried and true , like Sonic barrier, cabinet bracing and lambs wool. Wool is $20.00 per lb at Maddisound, you'll need 2 . They have the foam as well.
 And one very important mod that  may not have been performed on your version is the mid panel rebuild thats done at the factory. Check with Brian on this.

Stan

Thanks Stan!
My RM 40's do have the latest panels.

[Harvey]

I also have an older RM40 that doesn't have the pr vitrification done.  Could someone explain how this can make an improvement and not be just a change for the sake of change.  To me all your doing is adding weight to the cone which is the same thing as adding more putty. So then I'll have to remove even more putty.  What can I expect sound wise and how is it done.  I have my speakers apart right now while I wait for my midwoofer upgrade to come in.
Thanks Harvey B.

[ctviggen]

Harvey,

I believe it stiffens the surface of the cone.  It also affects the putty level (obviously, as the weight of the cone changes).  However, the cone distorts shape less, which leads to your ear hearing less distortion.

As for Q, lower Qs (basically) mean that the response is slower; higher Qs mean that the response is faster, so fast to overshoot.  I'm not sure which one would translate into "warmer". 

[ka7niq]

Harvey,

I believe it stiffens the surface of the cone.  It also affects the putty level (obviously, as the weight of the cone changes).  However, the cone distorts shape less, which leads to your ear hearing less distortion.

As for Q, lower Qs (basically) mean that the response is slower; higher Qs mean that the response is faster, so fast to overshoot.  I'm not sure which one would translate into "warmer". 

Higher Q is warmer, lower Q is faster

A sealed alignment with a q of .707 is considered optimum, a q of 1 would be boomy, and a q of .5 would be fast, but cold sounding

Personally, I have zero plans to vitrify my passive radiator.
Here is why.

The additional weight of the vitrification process cannot be removed from the passive, hence the ultimate range of the tuning is reduced.

Maybe with the increased out put of the new mid woofwers and higher crossover point, I can get away with it.

In MY room, I must run my RM 40's with lower putty levels then most to get enough warmth, and turn my levels down considerably.

This really makes the RM 40's very power hungry.

I wish Brian made some more efficient woofers for those in my situation.

I would GLADLY settle for 45 hz bass, with more efficiency, and simply use a sub.

[woodsyi]

Harvey,

You don't have to bother with the glue if you are also ordering CDWG (which I think is the most effective upgrade to my 40s) because you have to get lighter PRs which will already be vitrified. My take on bass change is that vitrified PRs have tighter presentation as long as you have enough damping factor and juice on your amp(s) driving the woofers.

[Harvey]

I don't know the damping factor of my amp...which I would like to recommend to for those on the cheap, it's a Counterpoint SA220.  It's a hybrid amp, tube input section with mosfet output-220 watts. They both work well together.  I don't expect to be able to do the CDWG upgrade for quite some time so if I want to keep things on the warmer side, do I have the pr done or leave them the way they are?  It might help to mention also, that with the upgraded midwoofers I'm doing the BH5 treatment and ordered TRT caps for only the midwoofer section, not the whole crossover.  I'm assuming it's just one cap per side.
Harvey B.