NBL advice please

Posted by: NigelP on 18 April 2002

I've been lucky enough to pick up a pair of ex-dem pair of NBLs and had them rigged up for about two months now. They are being driven passively by my NAP500 and had the modification to bring the NXO up to current specification. After much playing around I have the speakers about 9 inches away from the back wall and with a full two feet clearance away from those side projecting bass units. They seem to work best here but I would just like to get some more advice on the set up before making the assumption that they are working at their best. I was not particularly happy when I first bought them as they sounded nothing like the demo I had heard. I then came to the realisation that the setup and placement has dramatic effects. Anyway got any dos and don'ts for me?

Thanks
Posted on: 18 April 2002 by Andrew Randle
Moving the loudspeakers closer together or further apart has dramatic effects on the sound. I would guess that they need moving closer together. Try moving them about 6" towards each-other. If you haven't done this before then you must try it out. This has the result of giving more body to the performers and making the tunes more accurate.
Moving them closer to the back wall may also have a dramatic effect (particularly if you find the presentation needs to be heavier).

Check the suspension on the bass module. Also make sure that the loudspeakers are dead level. Also make sure that they are stable, in terms of corner-to-corner rocking.

Is the back wall an external or interior wall? Remove anything that is between the loudspeakers. Your NACA-5 is probably over the 3.5m minimum required length.

What is it about the sound that is lacking?

Andrew

Andrew Randle
Currently in the "Linn Binn"
Posted on: 18 April 2002 by NigelP
I would like to answer your questions and comments:
quote:
Try moving them about 6" towards each-other. If you haven't done this before then you must try it out. This has the result of giving more body to the performers and making the tunes more accurate.
I haven't tried this and will do so tonight. Will let you know what I find out.
quote:
Moving them closer to the back wall may also have a dramatic effect (particularly if you find the presentation needs to be heavier).
I had them right against the back wall and they were horrible. The trouble here is that they sit either side of the fireplace which protrudes by something like 6 inches from the wall. I moved them right out and then gradually moved them back until the sound from the bass cones didn't change to the "boom" effect I was getting.
quote:
Check the suspension on the bass module. Also make sure that the loudspeakers are dead level. Also make sure that they are stable, in terms of corner-to-corner rocking.
Done that and perfectly level and no rock.
quote:
Is the back wall an external or interior wall? Remove anything that is between the loudspeakers. Your NACA-5 is probably over the 3.5m minimum required length.

External wall with fireplace (blocked flu) between the speakers. I have a full 2 feet from the side of each speaker from the fireplace. NACA-5 is around 8m for each channel.
quote:
What is it about the sound that is lacking?
The bass was very "hard" and almost unlistenable on some music. This improved when I moved the speakers out from what must have been little caves and I think that the side bass units were resonating sound without it coming out into the room. I am pretty happy with them now but just wanted to be sure that I hadn't left something out.
Posted on: 18 April 2002 by J.N.
I neither have the room or the money for NBL's.

However; I have two friends with NBL's running passively from CDS II - 52 - 500. The two systems produce a very different sound in very different rooms.

I think the answer for you is that they are 'right' where they sound 'right' to you, given the restraints of where you can realistically put them.

One of the above mentioned friends is constrained to have them well into corners, firing down the room and gets an excellent sound.

Come on chaps; you know who you are!