RBH Sound PM-8 Monitor Measurements (from Audioholics)

[hardisj]

Not sure if you guys have seen this. I didn't see it mentioned anywhere. The review - by James Larson - is posted here (starting with 2nd page; the first is just intro stuff).
https://www.audioholics.com/bookshelf-speaker-reviews/rbh-pm-8-monitor/conclusion

These are ~$1600 USD EACH. $3200/pair. For the standard finish. More if you want fancier.

I replied to their YouTube channel post about it with the following:

Eek. $3200/pair for the 'standard' speakers? I'm not seeing that kind of performance in the supplied data. 1) Apparently a port resonance ~550Hz results in cancellation (dip). Maybe not a big deal audibly. But for $3200, that should not be there. 2) Some sort of high-Q breakup ~1200Hz. I'm guessing this is the 8-inch midwoofer (beaming is about 850Hz, so breakup above that is typical). 3) What is the crossover point for this speaker? If 48dB/octave is the slope, combined with the fact that AMT's can't generally cross as low as their dome-sized counterparts, then I'm going to guess they crossover is somewhere in the 2000-3000Hz region, based on the narrowing directivity met with wide dispersion again (per the SPIN data). IF that is the case, then what is going on @4-5kHz; cabinet diffraction? These are all educated guesses, but obviously without more information "guesses" is all they are. The (measured) performance is pretty bad. I'm sure with 8-inch woofers they have the benefit of having some output, but then again... AMTs.

Regardless of the root cause of the issues, based solely on what I am seeing, at this price the response should be immensely better. There are a lot of flaws for a $3200/pair of speakers.

My $0.02.

- Erin

Curious if you guys think I'm crazy. I'm just not seeing it.

 

[MZKM]

My comment on their post:

Why is the woofer on their site silver?

EDIT: Are the accent panels an attachment? If so, that changes the shape of the cabinet and will change the far off-axis horizontal response and maybe the baffle diffraction/step. So, that may address my comments below.

Honestly, not super impressed by the Spinorama, the ~3000Hz-5000Hz region is a bit wonky and dispersion between 600Hz-1500Hz is weird. It seems that they really didn’t do much DSP besides the crossover.

At $3200, I expected a bit better.

Gene replied that the woofers come in both colors (not stated on their site), and that vertical performance is great (it is) and that James loved them so they must be doing something right.

I wonder how much better the measurements would look with the panels off.

 

[hardisj]

My comment on their post:



Gene replied that the woofers come in both colors.

I wonder how much better the measurements would look with the panels off.

I didn't see your comment... but I do now. I agree. IMHO, RBH needs to go back to the drawing board on this one. Who cares about FIR filters if the final product isn't good? (not me)

 

[richard12511]

Not sure if you guys have seen this. I didn't see it mentioned anywhere. The review - by James Larson - is posted here (starting with 2nd page; the first is just intro stuff).
https://www.audioholics.com/bookshelf-speaker-reviews/rbh-pm-8-monitor/conclusion

These are ~$1600 USD EACH. $3200/pair. For the standard finish. More if you want fancier.

I replied to their YouTube channel post about it with the following:


Curious if you guys think I'm crazy. I'm just not seeing it.

I disagree that these are "pretty bad". I think we're in a bit of a bubble here at ASR, and that somewhat skews our standards. They're not great, for sure, and I see no reason to buy these when there are much better options for the price, but these are still flatter than most of what stereophile measures. I think we see a disproportionate amount of top tier speakers(Revel, KEF, Genelec, etc.) here at ASR, as those are usually the only ones people aren't afraid to send in.

*Edit: I see now this is supposed to be a studio monitor. That does somewhat change my opinion. SPDI seems to have some issues.

 

[hardisj]

I disagree that these are "pretty bad". I think we're in a bit of a bubble here at ASR, and that somewhat skews our standards. They're not great, for sure, and I see no reason to buy these when there are much better options for the price, but these are still flatter than most of what stereophile measures. I think we see a disproportionate amount of top tier speakers(Revel, KEF, Genelec, etc.) here at ASR, as those are usually the only ones people aren't afraid to send in.

That's fair. At least how we have been conditioned to see a lot of good stuff. But we also see a lot of bad stuff as well.

Still, for $3200/pair, I don't see any value here other than the fact they are active studio monitor speakers. An 8-inch woofer mated (seemingly poorly) to an AMT with diffraction effects and port resonance. That's what I see. And when I say that back to myself and then follow that with "for $3200/pair"... well... that's a no go.

 

[richard12511]

That's fair. At least how we have been conditioned to see a lot of good stuff. But we also see a lot of bad stuff as well.

Still, for $3200/pair, I don't see any value here other than the fact they are active studio monitor speakers. An 8-inch woofer mated (seemingly poorly) to an AMT with diffraction effects and port resonance. That's what I see. And when I say that back to myself and then follow that with "for $3200/pair"... well... that's a no go.

I edited my post after learning it's supposed to be a studio monitor. I think that changes things a bit. How do I view comments? I only see 1 comment that just says "Another cool review. Thanks Shady!"

 

[hardisj]

I disagree that these are "pretty bad". I think we're in a bit of a bubble here at ASR, and that somewhat skews our standards. They're not great, for sure, and I see no reason to buy these when there are much better options for the price, but these are still flatter than most of what stereophile measures. I think we see a disproportionate amount of top tier speakers(Revel, KEF, Genelec, etc.) here at ASR, as those are usually the only ones people aren't afraid to send in.

That's fair.

Still, for $3200/pair, I don't see any value here other than the fact they are active speakers. An 8-inch woofer mated poorly to an AMT with diffraction effects and port resonance. That's what I see. And when I say that back to myself and then follow that with "for $3200/pair"... well... that's a no go.

I edited my post after learning it's supposed to be a studio monitor. I think that changes things a bit. How do I view comments? I only see 1 comment that just says "Another cool review. Thanks Shady!"

They posted a link to the review via their YouTube channel. I can’t figure out how to link that post though.

 

[MZKM]

How do I view comments? I only see 1 comment that just says "Another cool review. Thanks Shady!"

Go to their YouTube channel, then go to Community then click on the PM-8 post.
YouTube doesn’t have anyway to link to these types of posts.

 

[heflys20]

Looks like they went back to the drawing board. Apparently, these speakers replace those. Not bad, but $3,500 is a lot, considering the competition:

RBH Sound 61/AX Active Monitor Speaker Review

The RBH Sound 61/AX is a fully active 2-way bookshelf speaker system that employs SOTA DSP with active crossovers and 400 watts of built in amplification for pristine, dynamic sound quality we review.

www.audioholics.com

 

[jhaider]

It’s striking to me that AH used one of their 2nd string reviewers (and one with a conflict of interest I didn’t see disclosed in the review) to cover these - furthermore, the measurements are both incomplete (no horizontal polar map, no Spin) and poorly sourced (from the mfg? The reviewer?).

 

[amirm]

from the mfg?

It says in there it is supplied by RBH. They have heavy conflict of interest there so the least they could do is measure it themselves. And post something that has bass response and not be gated and show only 500 Hz and up. Really low quality work here.

 

[jhaider]

It says in there it is supplied by RBH.

Where did you see that? Here’s the only sourcing information I saw:

“All measurements of the 61AX were conducted outdoors at 2 meters in an open parking lot by RBH Sound's facility.”

That relates only to where, not who took.

 

[amirm]

I read it as "All measurements of the 61AX were conducted..... by RBH Sound's Facility." No way they would schlep out there to measure something there outdoor.

 

[jhaider]

I read it as "All measurements of the 61AX were conducted..... by RBH Sound's Facility." No way they would schlep out there to measure something there outdoor.

Agreed it’s poorly written and edited, but “facility” is a place not a person. There’s nothing in there identifying the technician(s) or their affiliations. It could be the RBH dealer who wrote the review or it could be RBH personnel.

 

[amirm]

Oh, I think the "review" is written by AH folks. I was talking about the measurements from RBH. Don is a custom installer who did Gene's house and has now contributes to AH on content side (both videos and it seems now in writing). He has no technical abilities to measure speakers.