subwoofer with 272

Anto68 posted:

Pev posted: Also it was only £500 S/H - there's a few around if you search the usual places.

 

DD12 at only £500, I understand you correctly? An amazing deal

If I got a private sale of this type on the web I would think at a fraud

Yep - as a result of a wanted ad on the fishy forum. The seller even personally delivered it from Scotland to Somerset as he has relatives near here! 

Back on topic - I am now a big fan of subs but unless you have golden ears and endless patience I would only recommend getting one that includes help with setting up I was amazed at the number of parameters and the very real effect they had.  

ChrisSU posted:

Many active subs have the option of a high level connection, which, if using a Naim amp, should be taken from the terminals on your speakers. This is likely to use a cheaper interconnect than a low level connection from the preamp, and subjectively, is generally considered the better option for sound quality in a Naim system.

I am running 2 Totem KIN subs in my system connected the way ChrisSU mentioned above. These subs are small, extremely fast, tight, and great with music. No boom, but ooodles of nice deep quality bass when you need it. 

rohan posted:

Ardbeg10y posted:

Adam Zielinski posted:

Ardbeg10y posted:

Adam Zielinski posted:

I honestly think you don't need a sub whith those speakes and such a room. If anything:

• Install an XPS DR for your N272
• Good rack if you don't have one yet
• Upgrade to SL speaker and 4DIN - XLR cables
• PowerLines on all components if you don't have them yet

A NAP 300 is cheaper.

Of course, but may not be necessary. And with NAP 300 most of the above will be needed even more

Your suggestions will reveal the true capacity of the system, but he might be there by either repositioning of speakers (what ROHAN already tried), getting rid of the persian carpets, replacing the sofa by wooden benches etc ..

It must be truly disappointing to get such a nice line-up, considered as one of the sweet spots in the Naim hierarchy and then not having sufficient bass extention.

Is this the classical situation of being over-speakered?

I have also though for a while that it is perhaps a case of being 'over speakered' . Unfortunately as there was no way to audition proac in dubai , and based on an earlier comparison i did with SF venere 3.0, PMC26 and my friends older proac2.5. I decided to go proach for the sheer musicality. I was planning to buy a new proac d30r ( again not available to audition) . Then I spotted a great preloved d40r and got that shipped  although they were considered more power hungry, thinking the 250dr would be able to handle these speakers even at low vol.

So yes it is a trifle disappointing that having spent so much for what is a sweet spot for naim, I have to plug these gaps when I just want  get on and enjoy the music at all levels....

Anyway will try to audition a few subs and perhaps NAP300 ( but then have to flog the XPSDR and 250DR and take a hit)

 

Don't get rid of the XPS!! The more you improve the rest of your system, the more you will miss it.

Yes i realised i woudnt need to drop the xps as 272 would stay anyway and the xps does improve things a lot.

Thx

An alternative to using an expensive 'auto-calibrating' sub is the approach I have taken.  Connect the 272 sub out jacks to a miniDSP 2x4, then connect one of the outputs of the miniDSP to the low level input of the sub.

1  Use REW's room simulation mode to find a few candidate positions for the sub that should give an even LF frequency response.  Don't forget that the sub will need to be at least 1m to 1.5m closer to the listening position than the main speakers, to compensate for it's group delay (typically somewhere between 2ms and 4ms).

2  Use REW (or something similar) to measure the in room response of the main speakers (only).

3  set the crossover frequency of the sub to where the bass of the main speakers just starts to roll off consistently (look for the 'knee point').

4  start with the sub's volume control at minimum, then adjust it upwards to get roughly the right level (set by ear).

5  measure the in room response again.  You'll see peaks and troughs at the LF end.  where there is a peak, use the parametric filter capability miniDSP to reduce the sub's output at that frequency.  Note how deep the troughs are (ignore any very sharp dips, just look at the broader troughs) if they are significantly below the level of the main speakers, increase the volume of the sub.

6  Repeat step 5 until you have a fairly even response.  If you can't get a good response try a different position for the sub.  If you still can't get a good response then you'll need acoustic treatment in the room, specifically 'bass traps'.

7  Look at REW's 'Group Delay' plot and ensure that there's a smooth transition through the sub crossover region.  If the sub is leading the mains (i.e. has lower group delay than the main speakers) then either move the sub further away from the listening position or add a group delay to the miniDSP filter for the sub.  If the sub is lagging behind the main speakers (larger group delay) the move the sub closer to the listening position.

(8)  As a final optional check, look at the 'Minimum Phase' plot of REW to check the position of the sub.  If the phase through the crossover region stays within +/-30° then your position and crossover alignment are good; if it exceeds +/-45° then you may need to move the sub closer or further away (depending on the phase).

The advantage this has over auto alignment is that this will tell you if you need to move the sub, and also tell you if you need bass traps; where as auto alignment will just try to make the best of a bad position (and inevitably fail).

Thanks. I s

olved the problem at least temporarily by speaker placement close to room corner thankfully no boom.. also recalibrated the wife to accept a new min volume.

Mate of mine is an acoustic engineer and will bring a sub around to see if it makes a marked difference.. will report back.