Polk RC80i In-Ceiling Speaker Review

[dasherzx]

what is my purpose?
you play don don donki 24/7

 

[VientoB]

Where are people fitting their ceiling speakers? I was thinking one in a bathroom might be quite good. But maybe not due to the humidity?

 

[Robbo99999]

Sure. The math is simply the THD *percentage* of 86 dBSPL subtracted from that of 91 dBSPL. Since both are normalized (to their amplitude), the difference tells us how more distortion rose at 91 dBSPL vs expected. In other words, if distortion is linear, the difference would be zero. But if we have arrived at the non-linear portion of distortion graph, you get higher than zero value for the specific frequency. It is still work in progress but thought I share it.

Thanks for the explanation, that makes sense. I suppose though we already expect %THD to increase as SPL increases which is what we see in all your seperate %THD graphs for the different SPL's, but I suppose the new graph does show at a quicker glance at which frequencies it really starts to misbehave. As a seperate idea you could put all the 3 different tested SPL's onto one graph - so a seperate %THD line for each SPL overlaid on one another - yes you wouldn't be able to show all the different harmonics because there would be too many lines but you could have just the %THD line for each SPL displayed on the same graph - I think that would be another way to quickly see at what SPL and what frequencies it starts to get out of hand - which is basically exactly what you do in your headphone testing reviews - eg for example the following graph:

 

[5th element]

That actually measured better than I thought. Tweeters on a stick are awful.

 

[JDS]

This is a review and detailed measurements of the Polk RC80i in-wall/in-ceiling speaker. It was kindly drop shipped by a member and costs US $249 for a pair ($125 each).
View attachment 460354
Overall look is nice but that 1inch tweeter looks cheesy to me. There is a white metal grill which you had to push out with the mounting screws. Woofer is rated at 8 inches.

Notice the 5000+ reviews on Amazon averaging 4.5 stars.

I measured it using Klippel Near-field Scanner "baffle" mode where it computes the anechoic response of the speaker as if it were in an infinite baffle (getting rid of back reflection and edge diffractions).

POLK RC80i Measurements
Let's start with our usual CEA-2034 measurements even though it doesn't fully apply here:
View attachment 460355
Story starts good but gradually gets worse until we see massive ups and downs in tweeter range. I am guessing those are interferences from the tweeter to woofer and back. Listening window moderates them so they are worst on-axis. I measured the near-field response of the tweeter (not shown) and it was much cleaner. Given the variability in power response, EQ will be hard to do.

We see similar issues in directivity which is the same vertically as it is horizontal due to center position of the tweeter:
View attachment 460356

Normally you want a wide sweet spot for an in-ceiling speaker but RC80i delivers the opposite. Off axis is going to have significant colorations depending on angle.

Listening to the sweeps in the lab, I was pleasantly surprised by the power handling at 86 and 91 dBSPL. Only at 96 dBSPL did it get a bit unhappy:

View attachment 460357

I am working on better analysis of the distortion. In that regard, I computed the difference between 86 and 96 dBSPL. In an ideal world, as SPL would rise, distortion would rise the same amount, keeping the above ratio the same. Naturally we are already into non-linearity which means distortion is rising more than the SPL:
View attachment 460358

Please excuse the sloppy presentation. Excel doesn't let me choose a log scale for anything other than a scatter plot.

Here are the usual absolute distortion levels:
View attachment 460359

Impedance is on the high side which is good:
View attachment 460360
This reduces the impact of long speaker runs.

Step response is quite odd although it may have something to do with baffle measurements:
View attachment 460361
We see a number of resonances in the waterfall:
View attachment 460362

Conclusions
Judging in absolutes, the treble response is quite poor both from on-axis and directivity point of view. Then again, distortion is quite low considering what we are dealing with. And price of course, is excellent.

Personally I am enough of a snob to spend more to get more. But if you are on a severe budget, the Polk RC80i may be a decent option.
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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

KEF's coax ceiling speakers may be a bit more expensive, but seem a lot better executed designs.

 

[beagleman]

Looking at the "Listening window" etc, its not really horrible at all. On axis it is bad, but when do we hear something "on axis" when its above up and in a ceiling??

Not sure it would sound great obviously, but not would it sound near as bad as on axis "Shows"

 

[Madlop26]

KEF's coax ceiling speakers may be a bit more expensive, but seem a lot better executed designs.

yes but it is a 5k Invesment for a typical set up, I can't do that for ceilings

 

[beagleman]

It seems a good speaker for AM radio broadcasts because they are typically limited to 4,500 Hz. Other than that, considering the time and money required for ceiling mounting, it is a pass. Thank you Amir for a great review of a flawed product.

But VERY likely you will never hear the on axis sound as shown in the graph.
Far more reasonable to assume you will hear a lot of the off axis and early reflections, that will comingle and sound more reasonable overall.

What did they sound like when you listened to them with AM radio??

 

[JDS]

yes but it is a 5k Invesment for a typical set up, I can't do that for ceilings

The rough equivalent KEF ceiling speaker (the Ci160ER) is $400/pair

​

 

[SuicideSquid]

Given how poorly some other in-wall/ceiling speakers have measured and the fact that these are basically dead flat from midbass through lower treble, and totally decent up to about 5kHz, they seem like excellent value for the money and category.

Of course KEF's meta models absolutely kill it, but they're also 4x+ the price.

 

[alanca3]

Is THIS why ceiling speakers setups so often sound funky unless you're in the sweet spot?

I would say it’s a function of location and typical in-ceiling directivity. Even if the response were superb, the speaker fires straight down, is placed near boundaries, and the listener usually moves all around the space.


I have a large room with a fully in-ceiling 5.1 arrangement and I’m at the mercy of the power response. Other than broad EQ strokes (low-mid scoop and a high shelf), you just have to live with the variations.

 

[SuicideSquid]

Where are people fitting their ceiling speakers? I was thinking one in a bathroom might be quite good. But maybe not due to the humidity?

I have a set in the kitchen connected to a blutooth amplifier so I can listen to podcasts and music from my phone. I also have a set in my living room as my Atmos height speakers.

If you want to put a set in a bathroom, buy marine speakers, they're rated for water resistance so humidity shouldn't be an issue.

 

[amirm]

If you want to put a set in a bathroom, buy marine speakers, they're rated for water resistance so humidity shouldn't be an issue.

I seem to recall this Polk speaker is also rated for humid locations.

 

[refast]

the bad news is that I installed 10 of these in my new house for the surrounds, kitchen, dining and baths.... the good news is that I put genelec SAMs in my office/listening room! and I am pretty sure I can hear the difference!

 

[dasdoing]

How is it omni-ish at 8k and 13k? lol

 

[Torin Krell]

I always look forward to reviews of new coaxial (and hopefully reasonably coincident) designs and currently enjoy a variety of different coaxial speakers including Vintage Tannoy Reds, cheap Insignias, KEFs and Genelec Ones. Thanks Amir for all your efforts here!

 

[Jumu]

Thanks for the explanation, that makes sense. I suppose though we already expect %THD to increase as SPL increases which is what we see in all your seperate %THD graphs for the different SPL's, but I suppose the new graph does show at a quicker glance at which frequencies it really starts to misbehave. As a seperate idea you could put all the 3 different tested SPL's onto one graph - so a seperate %THD line for each SPL overlaid on one another - yes you wouldn't be able to show all the different harmonics because there would be too many lines but you could have just the %THD line for each SPL displayed on the same graph - I think that would be another way to quickly see at what SPL and what frequencies it starts to get out of hand - which is basically exactly what you do in your headphone testing reviews - eg for example the following graph:
View attachment 460442

I d love to see such graphs

 

[amirm]

It takes some manual work to create that comparison graph in Klippel (vs AP which does it automatically). But can be done.

 

[MZKM]

Reserved

 

[AnalogSteph]

How is it omni-ish at 8k and 13k? lol

It's a coax thing. Seems a bit high for breakup modes (except maybe the 8k), so I guess interference relating to the stick-out tweeter. I'm a bit surprised they made it work as well as it does with a passive crossover. A design like this is always going to have issues either on- or off-axis.