PMC Twenty.21 Bookshelf Speaker Review

[YSC]

Just seen this thread. I saved up for 2 years (my wife and I are poorly paid) to buy a "high end" pair of speakers, and in 2013 splashed out on some twenty 22 (at the time darling of UK hifi forums) - trading in some Castle Richmond 3i. Immediately regretted it, always felt thin sounding to me and I had massive buyers remorse tinged with guilt. Sold them for small loss 2 years later - replacing them with xtz 99.25, less than half the price of the pmc. Kept xtz for 5 years until seeing the DBR62 review from our Dear Leader. Halved price of xtz. So now I have speakers a 5th the price of the pmc, that I adore at least a 10th the amount. Thank god for this forum

I went a less terrible loss prior to joining here, just bought the KEF X300A where the mids have a bit of ackward response and slight boomy undefined bass. I enjoyed them for 3-4 years but mainly used the HIfiman HE500 headphone for music. until I read the review of Genelec and pull the trigger on the 8030C and never looked back (actually took the X300A for TV use, coaxial did wonders for family movie sessions and the bass boost from wall is welcomed) really loved this forum

 

[Pharos]

There is something very odd about our subjective experience and assessment of a speaker. Unlike a science based measurement, we are not the fixed objective, unaltering and static beings we may think we are. My perception of my setup varies enormously across a given period of weeks and days, whilst physically remaining the same.

I use FM as a source, because I am a radio fan, and also because that process allows me to get on with other things whilst listening. It also results in 'subconscious listening' as opposed to the intense approach involved when we are deliberately auditioning to assess equipment. To that end I bought a very well regarded Accuphase T-107 FM tuner in the summer, and also re-vamped my loft aerial gaining about 6dB with a new arrangement; the S/N is good.

Since then my response to the equipment in question, my speakers, have produced on FM sound ranging from faultless and similar to CD, to absolutely dire, even within one day, or just a few hours. One of my objectives was to be 'on the arse' of the BBC, whose quality some 50 years ago was regarded as beyond reproach, my attempting to monitor what they are doing.

It is obvious to me that what I hear now bears little resemblance to what I heard all those years ago In the BBC control rooms and studios, and in particular speech on R4 is very badly dealt with in mic. terms and in pronunciation; both surprising for an Intelligence station.

But in addition I suspect that what I perceive is variable because of internal psychological factors, we are after all concerned with far more important things in our lives, and these, entering our massive internal computers, must affect our perceptual ability. So can we rely on a snapshot subjective assessment of a speaker? This is I think an especially a valid question because we adapt to a new auditory experience because the main aim of the brain is to maximise its understanding of the sound from a survival point of view. It adapts to the new sound in order to 'see through it' in order to understand the nature of the source of the sound, and whether or not it represents a threat to us, and we are attempting to deceive it, hence the need for very quick changeover AB comparisons to attempt to avoid the adaptation.

I argue that the better the reproduction, the greater will be the variation in perceived sound quality because the system is adding no obscuring artefacts to the source. Does anyone else experience what he may consider to be indefinable variability with a system?

 

[welsh]

Rough review and hard criticism for a company that's generally regarded as producing top of the line stuff. I'm not going to discount Amir's scientific review, but I would like to recommend everybody to keep an open mind. In the end, Amir is only 1 person testing 1 single item/product. The strength of a brand should be based on the experience of the many. In the end, measurements are only that; measurements. Listening to audio, like so many other things, is a subjective experience. For example: Your watch might not be the most accurate watch out there but it doesn't mean that it's a bad watch. You might really personally like the design and it might compliment you. It's the same for audio/speakers.
That being said; I now want to listen to scientifically perfect speakers (without having to do all the room EQ)! I happen to own PMC LB1's (which I was able to get for $100 from a guy who didn't know what he was selling) and they have been great speakers to me. I know that I could easily do much better these days as audio technology has improved. I was looking at PMC's professional lines, like the PMC IB2. Unfortunately I haven't really been able to find any good reviews. But now with all the bad reviews that PMC's been getting if somebody wants to sell me some for cheap, let me know!

So you cheated the guy who didn’t know what he was selling?

 

[Zvu]

Why is that a cheat ? One should never take advantage of someones bad financial situation but if in the age of internet (and you can even have it for free in most public places) you are still uninformed about something you sell, it's on you.

 

[dfuller]

I've recently joined a Discord server with a number of audio professionals and it truly seems to be "cult of PMC" land. I sincerely hope their DSP'd pro stuff (twotwo line) measures better than this, because if this is what the pro line looks like... Yeesh. I'm rather wary of the fact that they quote their frequency response without even specifying what the cutoff points are - that kind of thing really sets off alarm bells in my head because it tells you literally nothing about the speaker's response.

At least ATC, who have their own issues with a general lack of bottom end, are entirely honest about their frequency response in their specs (last I checked, they quote +/-2dB as well as -6dB cutoffs). I suppose it does help that ATC isn't trying to reinvent the wheel with regard to woofer loading...

 

[617]

I've recently joined a Discord server with a number of audio professionals and it truly seems to be "cult of PMC" land. I sincerely hope their DSP'd pro stuff (twotwo line) measures better than this, because if this is what the pro line looks like... Yeesh. I'm rather wary of the fact that they quote their frequency response without even specifying what the cutoff points are - that kind of thing really sets off alarm bells in my head because it tells you literally nothing about the speaker's response.

At least ATC, who have their own issues with a general lack of bottom end, are entirely honest about their frequency response in their specs (last I checked, they quote +/-2dB as well as -6dB cutoffs). I suppose it does help that ATC isn't trying to reinvent the wheel with regard to woofer loading...

By audio professionals do you mean people who work in recording studios?

 

[dfuller]

By audio professionals do you mean people who work in recording studios?

Yep.

 

[keenly]

Yep.

There is definitely a PMC cult lol

 

[DanielT]

Hm, with so much damping, the efficiency becomes like a sealed box, or? If so build a sealed then. Why build these aisles? Whats the point?

It does not seem to be the easiest thing to get a good TL speaker.

 

[dfuller]

It does not seem to be the easiest thing to get a good TL speaker.

That's because it's a much trickier thing than standard bass reflex to design, and unless you damp it super hard, you get these phase response caused dips and peaks in the frequency response.

 

[DanielT]

That's because it's a much trickier thing than standard bass reflex to design, and unless you damp it super hard, you get these phase response caused dips and peaks in the frequency response.

And then it ends up being like a seal box I suspect, so what's the point? That regarding efficiency that is.Or am I thinking wrong now?

What are the benefits with TL?

 

[thewas]

That's because it's a much trickier thing than standard bass reflex to design, and unless you damp it super hard, you get these phase response caused dips and peaks in the frequency response.

And even more difficult for a compact standmount speaker.

 

[Kal Rubinson]

That's because it's a much trickier thing than standard bass reflex to design, and unless you damp it super hard, you get these phase response caused dips and peaks in the frequency response.

Also, the principle does not scale down well since the relevant wavelengths don't.

 

[mhardy6647]

Also, the principle does not scale down well since the relevant wavelengths don't.

Col. Klipsch was wont to say something similar.

“They make miniature tubes and miniature loudspeakers, but they have yet to come up with a miniature 32-foot wavelength.”

Klipschisms — Klipsch Museum Of Audio History

www.klipschmuseum.org

 

[Kal Rubinson]

Col. Klipsch was wont to say something similar.

Klipschisms — Klipsch Museum Of Audio History

www.klipschmuseum.org

I do recall that but I made no claim of originality.

 

[DanielT]

What I'm looking for is that it seems to be difficult to get, at least for PMC, a sensibly tuned, well-measuring TL speaker. Wouldn't it have been easier to construct a seald or BR instead?

 

[wwenze]

What I'm looking for is that it seems to be difficult to get, at least for PMC, a sensibly tuned, well-measuring TL speaker. Wouldn't it have been easier to construct a seald or BR instead?

Maybe. And maybe that's why most people do that.

 

[DanielT]

Also price vs performance:

PMC Twenty.21, US $ 2,000

Compared to, for example:

Elac Debut Reference DBR-62, US $ 600 a pair

Elac Debut Reference DBR-62 Speaker Review

This is a review and detailed measurements of the Elac Debut Reference DBR-62 bookshelf speaker. It was kindly purchased new and drop shipped to me for testing. The DBR-62 costs US $600 a pair from multiple sources/dealers. The DBR-62 comes in black and walnut finish or the distressed Oak and...

audiosciencereview.com

Que? Strange this world of HiFi.

Of course:

Home review

If you’re looking for a top class pair of small standmounters these are well worth a listen

www.whathifi.com

Welcome to:

That song by Tears for Fears was at least something good British.

 

[dfuller]

What I'm looking for is that it seems to be difficult to get, at least for PMC, a sensibly tuned, well-measuring TL speaker. Wouldn't it have been easier to construct a seald or BR instead?

Well, yes. That's why most people don't bother. TL designs are by and large a mess, unless they're huge. And even if they are, performance is not really any better than a traditional bass reflex design - or a traditional sealed design, at that.

Acoustic transmission lines are a solution in search of a problem.

 

[amarsicola]

Shame on me just bought the twenty5.24 few monhs ago as i was fooled by the sharp highs and boomy bass... All that happened before knowing ASR!
After few weeks i started to get fatigued, so bought a Umik microphone since i thought the problem was with the room, at that point i understood the main flaws were depending from the speaker.
...

Thanks to a good price from a well known Italian retailer (Di Prinzio) i'm now produly owning them...
Night and day!
My two cents on transmission line: all the frequency response graphs i've seen of a transmission line are problematic in the bass region. This technology cannot be implemented easily (if not at all) on a compact speaker, while on a large speaker its claim would be to make possible a great bass response from a 2-way speaker. The point is that price/performance of a 3-way + bass reflex is incomparably superior. After so much money thrown away for the PMCs now I can testimony it.