How To Improve B&W N802 Bass Response?


I’m not satisfied with the bass response of my current system in stereo. It seems weak and doesn’t seem to fill the room at low to mid volume. I’m looking for any ideas or suggestions on improving the bass response. My application is mainly 50/50 stereo music / multi-channel HT. Listening room dimension is 24’(W) x 17’(D) x 20’(H) with openings to living room, foyer, kitchen and sun room.

System configuration:
• Digital sources: Sony DVP-NS 755 DVD Player and Scientific Atlanta 8300HD Cable Box
• Digital-Analogue Converter: Apogee Mini DAC (1 week away from being replaced by Apogee Rosetta 200 DAC and Big Ben Clock Regenerator)
• Preamp: McIntosh C200
• Amps: 2 x McIntosh 501 monoblocks
• Speakers: B&W N802
• Cables: Mogami balanced XLR interconnects (soon to be replaced with Apogee Wyde Eye for all interconnects), Cobalt copper speaker cables bi-wired to N802s.
• Receiver: Denon 5803 (for HT only passing thru C200)

I had tried a few configurations along the way, though I’m not satisfied yet, they may be interesting tips for some of you with similar components:
• Canare L-4E6S Star Quad balanced XLR cables tend to “filter” out mid and high frequencies to a point that the sound becomes muddy.
• Belden 1800F XLR balanced cables are better than Canare where they are clearer and seem to give the illusion of sound stage opening.
• Mogami XLR balanced cables better than the above in my system. They are very transparent, clearer and sound stage opens up tremendously.
• Setting the output trim to +12 on C200 makes a lot of difference. It drastically improves details and sound stage even further.
• Connecting N802 low frequency taps to 8ohm and mid/high freq to 4ohm taps of MC502 helps. The bass response seems to be louder and the mid/high seems to be “sweeter” and just right.

I shall soon see what kind of performance improvements from the Apogee XLR cables, Rosetta 200 and Big Ben.

I’m also considering getting a good sub to extend the lower frequency. In my initial research, the SVS PB12 Ultra/2 ($2300) sub seems interesting. It has 1000W BASH digital amp and 2 x 12” TC Sound Ultra drivers. Anybody has any opinion about this sub for music application? I’m wondering how well it blends in with the N802s. I’m not sure how good the 1000W BASH amp is compared to McIntosh MC501 monoblocks. Would I be better off getting passive sub and let the 501’s drive it?

As an alternative to sub, would a 2-channel equalizer help boost the low frequencies of N802s to make frequency spectrum “flatter” at a given db? I hate to waste my investment on N802s, I mean the spec says it can go down to 30Hz. My reservation of EQ is it stretches out my signal path (dtx EQ has AD and AD built-in, in addition to my Apogee DA in the signal path). Not sure if this latency will lead to video syncing problem for HT application. Also, I don’t want to find myself having tinker with EQ’s instead of enjoying the music. If you have good experience with EQ, please share your experience about the brand(s) you tried.

I will appreciate any suggestions you may have on improving the bass response.

Thanks,
John
jteoh1
John,

I have a remarkably similar setup, and have experienced similar issues. My livingroom is 34x17x20 and opens into other rooms. I have a pair of N801s and they also seem to be lacking in the very lowest frequencies (or as a friend puts it, "missing that last octive"). I think some of the effect can be attributed to the shear volume of airspace that the 801s need to drive, even with their 15" woofers. But I also think that I'm experiencing room nulls / cancelations due to room dimensions and speaker placement. When listening to frequency sweeps, I can detect 3-6db drop outs at regular intervals.

I read this paper recently which suggested that multiple subwoofers, carefully placed to compensate for room modes might be the way to go: http://www.harman.com/wp/pdf/multsubs.pdf. I haven't yet experimented with this, so I can't give you my results. However, I'm considering 2 subs toward the back of the room to offset the woofers in the front. (One of these Saturdays I'll get down to taking some measurements!)

Warren
>>Buying subwoofers for high caliber speakers like the N802s is unnecessary.<<
Auaarons is way off base (no pun intended) here. Virtually every speaker system benefits from a subwoofer IF: The subwoofer is carefully matched with the main speaker system and it is postioned correctly in the room. Furthermore a subwoofer for each channel is superior to a single unit responsible for the entire system.
I’m thrilled to share with you that I’ve found the solution to my weak bass problem. I picked up the dbx equalizer (model 1231 for $300) this evening and added it my signal path, between pre-amp and amp, with balanced XLR connections. Wow, I was totally amazed what a difference this EQ makes! The bass now can extend way down low to 30Hz the B&W N802 woofers are capable of producing. The bass is extremely crisp, deep, tight, solid and punchy yet extremely musical. I can easily discern and appreciate every single low musical note. The N802s now sound like a pair of stereo subs and actually make the room rumble when watching Toy Story 2. I really don’t need a sub any more.

The EQ has +/-12db boost, it seems to “boost” the sensitivity of N802s, making N802s become alive! The midrange and high frequencies also benefit from this EQ. My system now sounds sweeter than ever.

I was looking at the Auralex acoustic treatments earlier today but was concerned about making my family room unsightly (sure won’t pass WAF). What a relief, this EQ did such a wonderful room correction job that I no longer need the acoustic treatments now.

Interestingly, I also installed the Apogee Big Ben (clock generator), nah, it didn’t improve the sound a single bit. My Apogee Mini DAC’s dual stage design is so jitter immune that making Big Ben absolutely unnecessary. The BB is going back…

Boy, am I satisfied with the big bass now! I’m glad this has been an inexpensive but highly effective solution. Thanks to all, nonetheless.

John
It's basically about getting the speakers and listening chair(s) where they give the best/flattest/most even response in relation to EACH OTHER...nothing more.
The room is basically a pool filled with bass modes/waves. You ideally put your listening chair(s) where the bass is the most even/balanced, and then placing your speakers where it compliments the reponse from the seating possition...were talking ONLY bass response here.
You can start by placing the 802's woofers/port where your head will be(once you've disovered your seating), then play some bass steady music while you move around near where the speakers are to be located, finding the best spot for bass response. Ideally you do the same for the other speaker, in a symetrical fassion. If not, you balance as close as possible and find a "balance" between them, keeping soundstage in mind as well.
You may then play test tones up to 300 hz with a sound level meter, and see how it measures. Flat/even is what you want for best dynamic range, reponse, etc.
You may then interchange the speakers for the seating possition! They correspond to one another.
Basically, if you're not getting good response, you can measure your system with test tones, an write down your measurements. If, say, you have a hole at 80hz/63hz,50hz, whatever, then you simply play the test disc at that(those) tones, and measure around till you find the spot(s) where the room couples well at that frequencies)...then move the speakers there and compare.
It's basically a balancing act.
I garantee those speakers can make bass. You just don't either have your seat(s) or the speakers(or both) set up right in relation to each other. That's it.
Other variables would be if you have a big bass hole/suckout due to structure or large trap of some sort. This is rare on a large scale, and is likely just setup error.