Sub disappointment!



Current set up is:
Marantz SR4300 Amp - preouts into Arcam to power the two front speakers - BW 601S2, Centre speaker is BW LCR60 S3, Rears are Mission M71i.

Just bought and added an sub, have to admit I hadn't heard it first as none of the Hi Fi shops stock it near me so I wen't from various recommendations, the MJ Acoustics Reference 100.

The sub is set up as follows:
Use the lo input right channel to connect to the amp.
Low level gain is set to 11 o'clock
Frequency Contour 120 Hz (LFE)
Phase set to 90

Question is am I doing something wrong or going deaf - for £350 I'm a little unimpressed with the addition to the overall sound, I either don't really 'feel' or 'hear' the base or when I turn the gain up to 1 o'clock I 'hear' the bass but it doesn't seem to fit into the sound i.e. I can hear it too much but still can't really feel anything - were my expectations too high?

p.s. I know I was a fool to not listern to it first but I thought with that many good reviews in mags and forums I couldn't go wrong!


Active Member
What are you listening to Movies or music? If music I really recomend using a high level cable, after fitting mine to my Ref 1 I REALLY noticed the difference.
Unfimiliar with your amps etc but is LFE enabled?
Also I would adjust LFE to either 100 or 80.

Ian J

I think that you may not have it set up optimally but I am no expert in using two amps so will leave it for someone else to answer.

Speakers set to small with all bass & LFE to sub, crossover on sub switched out so that amp controls bass management and try the phase at 0 to start with.


Thanks for the tips, front speakers are currently set to large, will try setting them to small to see what the difference is. Am only using the sub for Movies. The Arcam amps are a bit of a red herring as I use them for music but in combination with the Arcam (to power the FR FL speakers) with the Marantz amp for Movies. The Marantz displays LFE for the Sub but the Sub only displays LFE when I set the frequency contour to 120 i.e. full on - any further tips greatly appreciated.


Standard Member
Have you tried using Avia to check that you are getting a SPL?

Also try the sub in different places.



Active Member
If your'e gonna set the fronts to large you need to connect with the high level neutrik cable, otherwise do as I J says and set them to small, as much as iv'e noticed much of the soundtracks bass is often on the front left and right speakers.


Thanks for the tips, have switched the fronts to small and there is a great improvement. Only one last issue, when the Sub is set to LFE it gives off an audible buzz - anyone experienced this or got a solution?


Ref the buzz, try disconnecting the earth lead from the sub plug, my MJA Ref 150 buzzed until I removed the earth lead, I spoke to MJA and Denon about it, Denon reckoned it was down to MJA who agreed to see what they could do about it, but I have not heard anything yet. Hers Denons reply:
Dear Sir

Thank you for your e-mail regarding Denon products.

On some manufactures Subwoofers there is a circuit
that bypasses the earth so there is a clean signal
flowing through the amplifier to the Subwoofer (Kef
have introduced a switch on one of there subwoofers
to cut out this problem.

We would suggest connecting MJA to see if there is
away of cutting out the earth loop which can cause
mains hum through Amplifiers, also check to see if
you have a good quality Subwoofer cable from the
Amplifier to the sub.


Product Support

I will Email MJA now and ask for an update.


Weird, it only does it when switched to LFE though, whys that? Will find another mains lead and try it out - any danger in this though?


Originally posted by mcgillm
Weird, it only does it when switched to LFE though, whys that? Will find another mains lead and try it out - any danger in this though? [/QUOTE

Yes that’s right the Buzz is loudest on LFE setting, that’s what mine is set to.

It is not recommended by MJA, they tell me the earth is there for safety, it is your decision, but mine has been running without the earth since I got it in Oct 03, I just took the top off the plug and disconnected the earth, no Buzz!

Have a look at this thread:


Active Member
Are you using a GOOD quality sub cable. I have installed an MJ REF 100 with its supplied cable and had the same buzzing problem. (all the time but much worse on LFE) After replacing it with a QED PSW cable the buzz disappeared.
This goes for other subs as well

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