Drivers in VMPS RM2

RSorak · « **Reply #20 on:** 21 May 2018, 02:51 pm »

The CSS 12 PR's are just slighly larger in diameter than the stock PR's. I enlarged my holes w a drill mounted rasp. They dont need much maybe a 1/16"

Stimpy · « **Reply #21 on:** 21 May 2018, 03:00 pm »

Parts Express also sells 2 different versions of their Dayton brand of passive radiators. I've never used them, so I can't comment on performance.

https://www.parts-express.com/dayton-audio-sd315-pr-12-designer-series-passive-radiator--295-496

https://www.parts-express.com/dayton-audio-rss315-pr-12-aluminum-cone-passive-radiator--295-502

G E · « **Reply #22 on:** 21 May 2018, 04:12 pm »

Quote from: RSorak on 21 May 2018, 02:51 pm

The CSS 12 PR's are just slighly larger in diameter than the stock PR's. I enlarged my holes w a drill mounted rasp. They dont need much maybe a 1/16"

When I updated my RM30 to Series 2, I used the CSS 10" passive. It was just slightly too large for the existing hole. I then realized the rubber ring could be removed from the frame. It then fit perfectly without needing to dremel or rasp. And, the side grill covers fit over the passive drivers.

I used a 3Mm automotive product as a gasket. Sticky as all get out. Doesn't harden. Doesn't act like glue.

Now I am motivated to install my megawoofers this week.

Glad to hear Simon is finally getting his VMPS speakers. He is the one who got me started on them.

simon wagstaff · « **Reply #23 on:** 4 Jul 2018, 02:33 pm »

Any comments on whether the PARTS Express aluminum PR or the other one would be better. I am just not getting the bass I expect out of these RM@ and suspect this might do the trick. I have felt around and it seems that the surrounds are intact.

G E · « **Reply #24 on:** 4 Jul 2018, 08:15 pm »

Quote from: simon wagstaff on 4 Jul 2018, 02:33 pm

Any comments on whether the PARTS Express aluminum PR or the other one would be better. I am just not getting the bass I expect out of these RM@ and suspect this might do the trick. I have felt around and it seems that the surrounds are intact.

Check settings in your sources. Make sure front channels are set to LARGE not small.

Also check crossover settings in receiver. If set to 80 hz or higher they ain't getting the deep juice.

RM-2 speakers can produce usable sound to the low 20's without modification.

simon wagstaff · « **Reply #25 on:** 6 Jul 2018, 01:24 am »

Um, thanks, but you didn't answer my question.

Stimpy · « **Reply #26 on:** 6 Jul 2018, 01:40 am »

Quote from: simon wagstaff on 6 Jul 2018, 01:24 am

Um, thanks, but you didn't answer my question.

I remember Brian not liking metal cones on woofers. Though, I'm not sure if that would apply to passive radiators or not? But, there have been VMPS owners on AC, that upgraded to the CSS passives, and all seemed to like them. If me, I'd stick with the CSS. Especially since you can easily tune it from the front via washers. The PE passives would have to be removed, in order to tune them.

revg1952 · « **Reply #27 on:** 6 Jul 2018, 01:44 am »

I 'll throw my 2 cents in since I have used P.E. pR's.. For the money (less$) I think the Model: SD315-PR will work out just fine. I like specs better,17hz. Just my opinion.
RevG

revg1952 · « **Reply #28 on:** 6 Jul 2018, 01:53 am »

Just one more thought No matter what model of VMPS I sold or upgraded, The PR's were not very expensive in build quality or in materials used (they are treated paper).. Just my experience and opinion.
RevG

simon wagstaff · « **Reply #29 on:** 7 Jul 2018, 11:50 am »

I ran Audessey last night. It identified the RM2s as small with a crossover of 110 hz so that tells me perhaps something is up. The woofers seem to be getting a signal just fine. Time to open up the bottoms and take a look. Thanks for the input.

The 626 that I had rebuilt sound great, and they were identified as large with a crossover of 60 hz, so it's not a matter of incorrect measurements.

I have to say though that the 2 neo panels in the RM2 seem to convey the transparency in the lower midrange better than the single one in the 626. I am going to play around with the RM2 and see what I can do. They do sound very fine with them set as small and a crossover of 90hz. I will play around with the setting some more today, and take a look at the PRS.

G E · « **Reply #30 on:** 7 Jul 2018, 02:34 pm »

It could be a software/firmware bug, but double check all settings in source device and receiver. If all appears correct perform a Reset to factory settings and re-run calibration.

To rule out hardware issues in RM-2, connect a source with variable output to your power amp. Double check that front speakers are set to large, no low frequency cut off. If you get good bass, then look to your receiver and equalization software.

There is nothing to be gained by opening up the speaker and plenty to be lost with an errant screwdriver.

simon wagstaff · « **Reply #31 on:** 7 Jul 2018, 03:01 pm »

It is not a software bug.

I am taking a look at the PRs in a little bit.

simon wagstaff · « **Reply #32 on:** 8 Jul 2018, 11:59 am »

The saga continues. Yesterday I played around with the RM2s some more. I reran Audessey, still nothing below 110 hz, also now the channel levels were 6 db off, with one speaker 6 db lower than the other. I think the binding posts are not very good, I am not getting a good connection. My Morrow bananas don't seem to fit well. I have some bi-wire cables around, I am going to hook them up using those and see what happens. The bass response can perhaps be fixed by replacing the PR, but a channel imbalance tells me there is more going on. When these were right they sounded VERY good. I think the order of business is to open them up, check the wiring, look for loose connections. See what I find. Replace the Pr. If that doesn't do the trick there is a company in Gaithersburg that might be able to pull out the cross-overs and check them out, maybe replace some caps. Any other suggestions welcome.

Would it be useful for me to post some pics?

It will be a process, but I think all the drivers are fine, so it likely will be worth the effort.

Cheers!

Stimpy · « **Reply #33 on:** 8 Jul 2018, 04:51 pm »

Even though the RM-2's are technically bass reflex speakers, they still need a tightly sealed cabinet for the passive radiators to function properly. So, carefully check all the driver mounting screws for proper tightness. Also, make sure the woofer and passive radiator surrounds are in good shape. If old and worn, the passive surrounds can deteriorate, causing loss of bass. Check the rear input terminal plates as well, to ensure they're still tightly sealed to the cabinet?

Oh, a couple of other things. Do the woofers use rubber surrounds? Do they still feel soft and compliant? Rubber surrounds can sometimes harden. This would negatively affect bass performance. While down there, go around the whole surround, along the basket edge and cone edge. Is the inner and outer perimeter stilled glued down properly? If not, any loose areas need to be reglued, to seal the surrounds.

The only other trick to try, is re-tuning the passive radiator. You can buy rope caulk at a home supply store. I believe Brian used a piece roughly 7 to 9 inches in length. Remove any old caulk from the centers of the passives, and apply the freshly cut pieces. Just kind of spiral it into a blob onto the center of the passive. Then you start Putty Pinching. This process re-tunes the bass response to your room and equipment. This thread discusses VMPS Set Up & Putty Pinching.

https://www.audiocircle.com/index.php?topic=47927.0

As to the crossovers, Brian seemed to always use polypropylene capacitors. They should be OK, as they don't age like electrolytic caps. But, poly's can be over driven and over heated. That can cause damage. Visually check the crossover parts to make sure none looked scorched. While in there, inspect the solder joints. It might not hurt to reflow the joints. Look at the L-Pads too. Maybe clean them with some Deoxit. Once you spray the cleaner into the L-Pad, rotate the shaft fully from on to off, 30 to 40 times, to make sure the internal wipers get properly cleaned. This could help with the channel imbalance.

If all of that fails, I'll come up to take them off your hands...!

simon wagstaff · « **Reply #34 on:** 9 Jul 2018, 12:03 pm »

Thanks for all the input!

I haven't turned the l-pads yet, I will do so today. I hooked them up with some old Tara biwire cables I had lying around. Connections are good, the bananas are just a little bit larger then the Morrow ones I have. If I run room correction, and set the crossover to the subs at the recommended 140 hz, and adjust the channel balance, these things sound great! Super big soundstage, detail in the lower midrange is enveloping. I would be very happy with them, like this, funnily enough.

A little backstory. From the same guy I bought a pair of 626R. Sent them off for rebuilding by a guy who has done this before. He told me that the spiral tweeters in it were dead, and what is weird is that the cutout in the baffle was for the G ribbons, and that these tweeters were filled in around those cutouts with silicone. Weird. So the spiral tweeters replaced with the proper ribbons. He also said that there was no crossover on the woofers, just straight wired in. These sound nice now, and I have the frequency plot to show it. They still don't sound nearly as good as the RM2s.

My plan is to have at it with the l-pads, twist them a bunch, and see what happens.

Replace the PRs with the CSS ones, just because. It will be an upgrade? While I am at it it will give me a good reason to pop out the old PRs and have a look inside. Take off the woofers and get access to the crossovers and take a good look at them. I suspect that there may be some weirdness in how the woofers are wired up. They are definitely getting a signal, just not a lot. When I press on the PRs the woofer cones move, so there is a good seal in the cabinet.

I am not ready to let these go yet, sorry.

Stimpy · « **Reply #35 on:** 9 Jul 2018, 02:36 pm »

The RM-2's are capable of low 20Hz bass. So, your RM-2's should be outputting outstanding bass. The 12" active and 12" passive was the same combination used in Brian's original Smaller and Dedicated Subs.

http://pointillistic.com/vmps-audio/index.htm

RM-2 Specifications:
Bass: - 30cm (12") woven carbon fiber, 30cm (12") Passive Radiator
Mid:    - two rectangular 10 x 20 cm (4 x 8") Neo ribbons, 280 Hz - 6.9 kHz
Treble: - FST, 6.9kHz - 30kHz
Impedance & Sensitivity: - 4 Ohm (3.6 min.) 91 dB/1W/1m
Power handling: - 300 W rms / 4 Ohms, 20 W min.
Frequency response: - 22 Hz - 25 kHz +0/-3dB
Dimensions & Weight: - 114H x 38W x 41Dcm, 55kg (45"H x 15"W x 16"D, 120 lbs)
Output levels and distortion: - max. 1% THD fullrange/1 W, max. 112+ dB SPL / 1 m
Finishes:    - standard lite oak, dark oak

Dedicated Subwoofer Specifications:
Drivers: - 30 cm (12") WCF Megawoofer bass, 30 cm (12") Passive Radiator
Crossover: - 90 Hz at 6dB/octave, adjustable high pass speaker level
Internal wiring: - 12 gauge Monster Cable
Impedance & Sensitivity: - 8 Ohm, 90 dB/1W/1m
Power handling: - 300 W rms / 4 Ohms, 20 W min.
Frequency response: - 24 Hz - 600 Hz +0/-3 dB
Dimensions & Weight: - 69H x 37W x 42Dcm, 38 kg (27"H x 14,5"W x 16,5"D, 84 lbs)
Output levels and distortion: - max. 2.5% THD fullrange / 1 W, max. 112+ dB SPL/1m
Finishes: - standard lite oak, dark oak

Also, before you get too involved, you should probably check the internal wiring phase of the 2 speakers. You could have one woofer wired out of phase to the other. That would definitely cancel out bass.

Pull the woofer on each speaker. Double check that the wiring matches up between the speakers. + to + and - to - are correct and match. Check the wiring at the crossover too, and make sure that each matches one another as well.

One thing, if the woofer is using Monster Cable wiring, in my experience; it had a tendency to tarnish and decay over time, and turn green! It might be worth cutting the wired ends free, restripping and exposing fresh wire, and resoldering it. It can't hurt.

You sure I can't come up and "help"???

simon wagstaff · « **Reply #36 on:** 9 Jul 2018, 04:16 pm »

I have a pair of the smaller subs that I am running as well. I upgraded them to the super mega woofers and big bump passives as few years ago, while they were still available. I have the old woofers around, but I don't think they are the carbon fiber one. Are the super-mega woofers still available? Those things are massive. huge surrounds

Might get even more bass from the RM2 since the cabinets are so big?

Really do love the sound.

So I will stick with the plan, rotate the l-pads, order the new PRs from CSS, when they come in I will plan on taking everything apart and checking it out. I am hoping I have decent access to the crossovers through the woofer hole?

Want to help? Sure! I am in Frederick Md. I'll even supply the beer.

Stimpy · « **Reply #37 on:** 9 Jul 2018, 05:00 pm »

AC member Patrick Malaga bought all the old VMPS stock. Pat advertises on Craigslist that he still has 10" & 12" mega woofers available. Oh, this is one of his CL ads. It might be worth checking into?

https://sfbay.craigslist.org/eby/ele/d/vmps-new-subwoofers/6623938061.html

Not sure about super-mega's. Though, I have a pair of super-mega 6.5" wcf woofers. I need to decide how I want to use them?

And hey. No beer needed. I'm an iced tea, diet soda type of guy. Sorry, I'm weird!

simon wagstaff · « **Reply #38 on:** 9 Jul 2018, 07:17 pm »

I sent him an email, just in case. My guess is the drivers are fine. More likely to be a problem with the wiring.

That's OK, I drink plenty of green tea myself.

simon wagstaff · « **Reply #39 on:** 27 Jul 2018, 02:01 pm »

Any way for me to get the schematics for the crossovers in the RM2 SDE? There is a channel imbalance of about 8 db that I think is due to dirty l-pads. Processor still shows speakers as small with crossover of 110 hz. Given the condition of the 626R anything could be happening in there.

Even with these issues they sound FANTASTIC. Best speakers I have owned. Truly.

I purchased the replacement passive radiators and will have them installed. just because. I have a local guy who will take a stab at them. The crossovers for the NEO and Ribbon are fine, I might look at some cap upgrades. I don't really want to change a thing there.

Something is likely up with the woofer crossover. I don't think they are out of phase, because Audessey measures them individually.

Worst case scenario is I will just hard wire the woofers to the binding post, and use the crossover in my processor at 250 hz and bi-amp. That's the highest setting I have.

Thanks!