Recommendations for a new subwoofer?

I have struggled with integrating subs. I tried dual RELs with my previously owned ATC 11s with some success but had none with my new Harbeth C7ES-XDs. No matter what setting I experienced a loss of transparency, increased midrange warmth and a less open soundstage. When I turn off the sub the soundstage opens up and the atmosphere and air return. I believe it’s because these subs bleed into the lower midrange, warming it and moving it forward. 
 

I’ve since sold the RELs. Plus these types of  “subs” are really bass enforcement. My Harbeths have really good output to about 40-45hz. So crossing over at even at the low 30s affects the lower midrange. Subs such as the REL T Series are just bass reinforcement. And they roll off into the midrange. I’d need a sub that can handle 20-30hz and with a steep roll off to avoid muddying up the lower midrange that can also allow a low crossover below 30. . 

@jfrmusic 

“I’ve since sold the Rels”

l agree with your decision. I have said a lot of good things to endorse the brand on this thread which might appear odd. Honesty and not blind biased judgement should not be on here, but yes l actually agree with you….but only in your case.

l use 40 year old Acoustic Energy AE1 speakers on their designed pedestals. I bought some newer Acoustic Energy Reference 1 speakers thinking it was a good choice to upgrade. The two Rel T9i subs l have just would not meld with the new ones…..too much bass and my settings were so low on the subs to almost make them redundant. The problem however was not with the Rels but with the speakers.

The Regerence 1’s bass response is formidable for the size of speakers. They go down to the 40Hz area you talk about. The Rels were just filling in the last 10 Hz of their specification. They were almost off just filling in one octave of range.

I lived with the new speakers for a few weeks and realised there was just no grand spacious and beguiling sound coming forth. I switched back to the old AE 1’s and put the Rels on again…..The magic returned… large soundstage and dynamics.

l came to the conclusion that the newer Reference 1’s didn’t need any subs, they were that good with just the last octave missing. End of story… l am now still using the original 1984 Acoustic Energy AE1 mk1’s and the Rels.

l think your speakers must have had the same roll off and a bit of overhang on the bass response to make the Rels meaningless.

For me it proved the older speakers still hold their own but with bass reinforcement. The newer ones are now in my second system where the extra bass is not required.

Hope this may help explain some other aspect of sub or no sub integrations 

I've never had subs in my 2 channel systems until now, i'm waiting as I write this post on a pair of REL special carbons to be delivered.  I did look at the T9s as well as some other brands, but I landed on the REL's based on speed and the particular model to match the rest of my gear.  I'll post an update once i have them setup on ease and sound. 

@mylogic 

Yes the same conclusion I had. The Harbeths don’t really need a sub. And if I wanted to add that octave between 20 and 30 I would need a sub with a crossover  below 30 and a steep fall off that does not affect the upper bass and low midrange. 

@jfrmusic 

The only other small to mid size pedestal speaker l have owned to have had the same bass response is Mission 770 Freedom’s. The front port could blow out candles and rustled my fern plants as if King Kong was behind them.

l still have them and can’t bare to let them go as l fire them up occasionally and have a blast sans Rels.