New Rel T5i. Anyone heard them?

@murphythecat

A question here on the T5i and its ability to blend with speakers. I read your comments on SH forum with the T5i not being able to use with a Harbeth speaker because the crossover on the T5i would not roll off enough below 55Hz. I am not versed in using subwoofers, so I am rather confused about this. And I may not be understanding what you said.
What I am considering is to pick up a T5i to augment a center channel speaker in a home theater system. I would be using the Speakon high level connection cable. This would not be for the LFE track. The center speaker is a Polk LSiM706, which is rated down to 50Hz, -3dB. Basically, the goal would be to turn the Polk into a full range speaker. The sub would sit on the floor directly below the Polk speaker.

https://www.polkaudio.com/products/lsim706c

Could you comment on whether or not this T5i would or would not work with the Polk speaker for my purpose? The frequency response would not have to be perfect. It would just need to extend the bass reach of the Polk speaker.

yes, my mesurements of the REl t5 and rel t5i made clear that at the lowest setting (30hz) on the knob, the rel t5or t5i only starts to roll off around 55hz. therefore, if your speakers are -3db at 45hz, you will get a quite serious bump at from 40hz to 80hz, making the sub imo useless

IMO, its only with the P3esr or Atc scm7 which are about -3db at 65hz that I could have decent integration. I think the rel t5/t5i only works with very small speakers that a limited in extension.
if your speakers extend down to 50 or even 60hz, i dont think tis a good match.

and tbh, a 8 inch sub is really only meant to go with very small 5 inch or 4 inch based speakers. makes no sense to add a rel t5 with speakers using 6.5inch or 8 inch woofers.

my recommendation? get bigger speakers or get a real sub with at least a 12 inch woofer. those rel t5i with their weird ass roll off behavior are toys

@murphythecat
Thanks, well that's not good, since I wanted to use the REL's Speakon connection.  I wonder if I could keep the volume on the sub low enough to extend the center speaker's bass just enough.

Why would you want to run a center channel full range?   Home theater is designed to roll all the speakers off below 80hz.  Take advantage of that.

Because the center channel, just like the front L/R and surround channels, is a full range channel, and it is independent from the LFE channel.  I like to hear the full frequency range of that channel.
The problem comes in particularly with deep male voice, a good example of which occurs with Russell Crow's voice in Mummy.  If you saw the movie at a theater, you know his voice in some scenes should be positively subterranean.  I don't think the LFE channel carries the lower frequencies of his voice.  And I have tried in vain to set crossovers on both subs and AV receivers to get that vocal quality in deep male voice.  The only way to get it is with a true full range center speaker.
I have seen a store demo of a HT setup in which they used the REL Ti series of subs to augment and extend the bass of the front L/R channels, and the improvement was great.  They employed a separate sub for the LFE channel.