About the KEF Q150 bass

Hi, I'm kinda new in the "audiophile" world. I've tried already quite a few speakers/amps and recently I've sold my Q acoustics 3020s for a pair of KEF Q150. I'm quite happy for the sound except for the bass response and I don't know if it's because of my amp, or if it's just how they're supposed to sound like.
I get very loud deep bass, they sound quite bloated and they lack definition / punchiness. I don't feel the bass when in certain sound I know I should feel it. They're currently powered by a Marantz M-CR511 (40w in 8ohms), could the problem be there?
To be more specific, they're in a 20 square meters room, both on 60mm stands, 30cm from the wall.

I really like the details I get in the medium and high frequency but I'm thinking of returning them because of the lack of punchiness. In this small room I also don't want to purchase a subwoofer.

 

Are you using the port plugs? I have found ALL of my KEF speakers sound better with the port plugs. You might want to pull them out from the wall a bit more also. Don't give up until you're sure you have good placement. You might be sending back a speaker you actually really like.

 

I tried them with and without the port plugs but I didn't get a really big difference bass wise (at least in the punchiness department), and I got the feeling that I was loosing some soundstage, is this possible? I'm gonna try to move them a bit more in the room but I don't have a lot of different places I can set them here. Sound wise, it's definitely an improvement over the Q acoustics but it's just that bass response that's bothering me.

 

I also want to add that I have the Q100, kinda the little brother of the 150 and I thought the bass was tighter than my mains (R500), but obviously didn't go as low. They're being driven by a much more powerful amp than yours though. The amp can definitely effect bass control. I didn't find them boomy at all.

 

Can you tell me which amp you’re using? I usually don’t listen to my music very loudly but maybe a more powerful amp can improve the sound even at low volume?

 

It's not about being loud. It's about control. I auditioned them with my Parasound Hint. One thing I noticed when I got my first pair of actually good speakers is that I could really hear my room for the first time. My R500's sounded boomy at first until I spent a lot of time moving them around and then did a little corner treatment to tame the bass. Now they sound incredible. They also needed some time to break in before the bass sounded right. Maybe your old speakers were a little bright but sounded more flat because your room is bass heavy (most rooms are). You'd be surprised what small changes in placement can do. I mostly suggest just pulling them away from the wall a little. Remember that they're rear ported. Front wall proximity can have a huge effect.

 

I don't think the problem is the Marantz. From your description, it sounds like some kind of bass over-reinforcement (at some frequencies) and cancellation (at other frequencies). Especially as plugging the ports didn't change much. Try moving the speakers to radically different places, and even change your listening position, temporarily.

It could also be that, like many 5" speakers trying to sound big, the KEF Q150 *may* have a kind of bass bump to sound "stronger." Can you change and try a Q350 with the bigger woofer? That got some very nice reviews.

 

Ok so I spent hours listening to different musics that I know and placing the speakers at different positions in my room. I finally found something that sounded good! Without any ajustement on my receiver I finally was able to detach the voice of Jack Johnson from the bass in "Middle Man". The only problem is that it was almost in the middle of my room and facing a corridor so I could not let them there but what's sound the closest at the moment is when I place them in their original place and change the output frequency characteristics to cut the low frequencies of 60 Hz or under by –12dB/oct. Still not perfect I guess because I feel like I'm loosing some bass...but I'll try to buy another amp later if I can to see if it improves. Something like a Marantz PM6006, I heard that it might have better control than my AVR. I won't be able to try the Q350 as it's a bit over my budget at the moment and I thought that for the size of my listening room the Q150 would suffice.
Thank you for the tips!

 

I went through a very similar issue, and tried all sort of things to fix it: EQ, moving speakers, different amp with better control, even different cables... you name them. Nothing really worked, so I finally understood that it's the room, not the amp or the speakers.
I've come to the conclusion that the only thing that works (except for placing speakers in the middle of the room, which would bring a whole different kind of issue) is putting some sound absorbers or diffusors in the corners of the room, or on your first reflection points.

 

I didn't know that positioning would have so much impact. When I placed them in the middle of the room facing the corridor, there were like totally different speakers, so much more mids, less bloated bass. Can't wait to move out to another appartement now haha...

 

Your corridor works as a natural bass trap. There are numerous articles and forum threads dedicated to bass trapping. I would absolutely do that before bothering with a new amp. Doing this will ensure that all future hardware purchases will sound their best. You'd probably buy a new amp to find you still have the exact same problem.

 

The bloated bass is the result of KEF's choice of enclosure alignment.. they want to give the impression of more bass by allowing ripples in the pass band.
Just like in the LS50s.
So to change the alignment, the use of the port plug is the only solutiuon, with the addition of a subwoofer, that would have to be crossed-over too high imho to sound nice and integrated.
Without the use of port plugs, solutions range from better placement to an amp with greater damping factor to a different choice of cable gauge.