PDA

View Full Version : Underwhelmed by Subwoofer



Alp
20-01-2018, 17:03
I had never tried a subwoofer before in my AV set-up which is a Marantz NR1403 AV Amp powering a B&W HTM2 centre speaker and the pre-outs going to my monoblock amps to drive a pair of B&W 804N speakers. Without the a subwoofer, this all sounded pretty good but I felt it was missing some low end umph. I bought a B&W PV-1 subwoofer on e-bay for 400 plugged-it in, connected it to the Marantz, ran the set-up using the Audessy and sat back to play a few movies to hear if there would be a difference. I have to say I was underwhelmed by the result, there is barely any difference. I then manually set the crossover frequency to 40Hz, but no change.

The 804Ns go down to about 45Hz and the PV-1 has plenty of power (500W) and goes down to 21Hz, so I was expecting an improvement. Any thoughts why this might not be?

struth
20-01-2018, 17:07
set it a fair bit higher. say 100hz to start

Firebottle
20-01-2018, 17:54
It rather depends if there is the low frequency energy actually there.

My sub is set to cross over at 40Hz, with normal radio programs it makes little (no) difference, when the low bass lines are there it is very satisfying.

Alp
21-01-2018, 16:05
Thanks I will try 100Hz and see if it makes a difference. As Firebottle noted, it of course depends on the content in the source. I tried films which were supposed to have great bass.

CageyH
21-01-2018, 17:08
I would check the set up again.
When running movies, my similarly powered sub sub (https://www.xtzsound.co.uk/reviews/sub-1x12) makes a massive difference.
With the HiFi, I have a smaller sub (MJ Acoustics Pro 50) which is barely noticeable, but that is how I want it.

Macca
21-01-2018, 17:33
What's the reference for it going down to 21hz? Does not seem to be any spec about this on the B&W site. My guess is that it is not doing much useful under 50hz.

If you want proper sub bass you'll need a big REL, or a Paradigm. Very few subs have useful output below 40hz and those that do tend to be large and expensive.

CageyH
21-01-2018, 18:06
If you want proper sub bass you'll need a big REL, or a Paradigm. Very few subs have useful output below 40hz and those that do tend to be large and expensive.

Or an XTZ, Velodyne, SVS etc.

jandl100
21-01-2018, 18:07
Where is the sub sited? Maybe you have just hit a room null? Does the bass appear anywhere else in your house?

The TechRadar reviews are usually pretty reliable and they give it a decent write-up. So there is probably decent performance to be had if you shuffle things around a bit.
http://www.techradar.com/reviews/audio-visual/hi-fi-and-audio/hi-fi-and-av-speakers/b-ampw-pv1-98121/review

Stryder5
21-01-2018, 18:22
I didn't find Audessy very good, after saying that did you follow Audessy instructions using the microphone in all the different positions it requires?

I turned it off eventually and set up by ear.

I also found using high level inputs to the sub bettered the low level input.

Alp
29-01-2018, 20:41
I didn't find Audessy very good, after saying that did you follow Audessy instructions using the microphone in all the different positions it requires?

I turned it off eventually and set up by ear.

I also found using high level inputs to the sub bettered the low level input.

I did follow the Audessy set-up, using the microphone in all 6 positions several but to no avail. In the end I went manual as you did. I made sure the AV amp outputs bass to both the Mains and the Sub (it was doing Mains only) and set the cross-over frequency to 100Hz. Audessy had set the sub levels at something like -7db so I tweaked this to -5db (also I tried -3db and it was too much - really shaking the room) which leaves it adding weight when needed but not overbearing. I am sure there could be more fine tuning but I am pretty happy with it now. Thanks to everyone for their advice!

Alp
29-01-2018, 20:44
What's the reference for it going down to 21hz? Does not seem to be any spec about this on the B&W site. My guess is that it is not doing much useful under 50hz.

If you want proper sub bass you'll need a big REL, or a Paradigm. Very few subs have useful output below 40hz and those that do tend to be large and expensive.

From the PV1 Brochure "3dB 21Hz – 31/110Hz adjustable (EQ at i)"

Macca
29-01-2018, 21:16
From the PV1 Brochure "3dB 21Hz – 31/110Hz adjustable (EQ at i)"

Pretty good performance. Might look out for one myself now you've established the problem was Audessy.

Primalsea
29-01-2018, 23:49
My theory is that with subs although the goal is to extend bass response you primarily tune the sub so that it acoustically sums with the other speakers in order to better align the bass frequencies and extension of those frequencies is something that happens as a result. If you try to just extend tha bass without fine tuning the way the sub sums with the other speakers the result can be disappointing.

The same for supertweeters. You don’t actually listen to the supertweeter you listen to the acoustic sum of the supertweeter and the tweeters of your speakers.

walpurgis
29-01-2018, 23:52
My theory is that with subs although the goal is to extend bass response you primarily tune the sub so that it acoustically sums with the other speakers in order to better align the bass frequencies and extension of those frequencies is something that happens as a result. If you try to just extend tha bass without fine tuning the way the sub sums with the other speakers the result can be disappointing.

The same for supertweeters. You don’t actually listen to the supertweeter you listen to the acoustic sum of the supertweeter and the tweeters of your speakers.

Spot on.

Although I would have said 'acoustically gels' rather than "acoustically sums".

Primalsea
30-01-2018, 00:13
Spot on.

Although I would have said 'acoustically gels' rather than "acoustically sums".

But potato, batahaa (as us cockneys says, guv).

Marco
30-01-2018, 09:25
If you want proper sub bass you'll need a big REL, or a Paradigm. Very few subs have useful output below 40hz and those that do tend to be large and expensive.

I can't deny the truth of that statement, but as you know I've got a pair of these little chaps, fitted with 12-inch drivers, strategically positioned in my lounge (albeit not a massive space), and the low-end 'oomph' they provide with movies (especially bomb explosions), in conjunction with my Celestion 15XRs (I suspect their ABRs also help in that respect), is fantastic:

https://imagizer.imageshack.com/v2/xq90/922/v93C6H.jpg

Unquestionably, they make a considerable difference, and not just with movies, but also 5.1 music SACDs/DVDs and YouTube videos. Cheap as chips, too: around 80 each from Richer Sounds! :)

I think how good an effect you'll get with subwoofers, is as much down to careful positioning and adjustment, and seamless integration with the room (size, especially), as anything else. Alastair, I hope you sort your sub issues out soon :cool:

Marco.