RC80i No Bass

LinesProductions

Hi, I recently bought a pair of new RC80i speakers after reading all the rave reviews. Before cutting a big hole in the paster board, I rigged them up to my technics amplifier to test them out. I'm new to recessed speakers but have used many standard bookshelf and studio reference monitors from various brands over the years. Although the RC80i is capable of creating a lot of volume, they sound incredibly thin and tinny. (While the volume was down I was confusing them with my echo dot speaker!) I've tried dropping them in a wooden box to see if that helps, which is does marginally but nowhere near enough. Is this standard for the units that aren't installed into a wall / ceiling? and is there anything I can do to improve the base response during installation? will installing them in a wooden cabinet help? The great reviews I've read, (some of which say these give you the best in class bass for a ceiling speaker) are a county mile from the sound I'm hearing, so I'm assuming I either have a defective set or I'm doing something wrong. Any help or advice is much appreciated. Cheers

Inscrutabl0915

Have had other in-wall/ceiling (not these, but may be shopping for some soon) ... these are designed for an infinite baffle mount, so you will need a very large enclosure to mimic that ... a bare minimum of 10x the driver displacement. Perhaps you did not? Not sure you can get the requisite Thiele parameter (Vas) or at least the excursion (Vmax) with which to calculate Vas.

Inscrutabl0915

If not, on the conservative side, let’s use another known 8-inch driver ... say the Dayton RS225 ... Vas is about 2 cu ft, so you need a 20 cu ft box.

F1nut

They need an enclosure, which will be the space behind your wall/ceiling.

LinesProductions

Thanks for the info, very helpful. My box was certainly not 20 cu ft !!

VR3

Better test would be to mount them in the center of a piece of plywood

Kex

Yeah...

I’ve installed RC80i before, as a temporary 5.1 HT setup. They boast decent numbers with an 8” woofer, directional 1” tweeter, 50Hz-20kHz frequency response and an efficient 90 dB rating (which makes them very easy to drive, even with just a receiver).

The truth is, I never found them very good. They are an entry level speaker, and certainly acceptable for their price point, but even if you build an MDF enclosure behind them, with foam filler inside, you won’t ever get impressive results IMHO. There are many other affordable Polk speakers that are much better, but those are the only in ceiling ones that I’ve ever tried, so I can’t offer any comparison from personal experience.

You will definitely need a subwoofer, and that will make a significant difference. Just don’t expect too much from these. My HomePod plays lower and with much more authority, using a 4” high excursion woofer (7 tweeters, and 6 microphones for automatic room tuning).

VR3

There are no enclosures that will work well with a woofer designed for ib, your best bet is a large baffle free air that separated the front and back wave as much as possible

Kex

VR3 wrote: »

There are no enclosures that will work well with a woofer designed for ib, your best bet is a large baffle free air that separated the front and back wave as much as possible

Please elaborate, and dumb down for mere mortals! 😂

Thanks! 🙏

Inscrutabl0915

Kex wrote: »

VR3 wrote: »

There are no enclosures that will work well with a woofer designed for ib, your best bet is a large baffle free air that separated the front and back wave as much as possible

Please elaborate, and dumb down for mere mortals! 😂

Thanks! 🙏

‘Infinite’ ... think of the baffle (surface to which you are mounting the speaker) extends in all directions forever ... the speaker cone moves back and forth, compressing air (making sound) both times ... the infinite baffle is keeping the back wave coming off the speaker cone (when the cone moves backwards) from interfering with the front wave.

Technically, you CAN have an enclosure, BUT it has to be so large that it has no effect or acoustical support for the driver [hence my recommendation of the minimum threshold of 10 times the volume displaced by the driver Vas ... a combination of the cone’s excursion Xmax (linear movement in and out) and the cone’s projected area].

An IB can play very low, with very low distortion, but is easy to overdrive and is designed very differently from one made to go in a sealed or ported enclosure.

VR3

What he said

I run a full in ceiling setup, ib floor subwoofer and in ceiling on my porch.

All of the speakers exceed their bass rating performance, so if Polk is saying - 3db 50hz, you should expect that or better when properly installed.

I'm running the 90rt on my porch and while the bass is far from clean, it does put out copious amounts! They are rated at 43hz - 3db and down to around 30hz -10db

Kex

Thanks guys! Note on acronyms for the non-initiated: IB = infinite baffle.

Hadn’t realized that these were designed to be left open (although I never enclosed them, since it was always intended as a stop gap setup in my case).

I would expect the RT range to work much better than these RC but there’s nothing like that listed on The Polk Built In Selection anymore.

90-RT on sale on Crutchfield though, for $200 each. Looks like a much better design that the RC too.