amplifier imbalance

[Murphyv310]

Mark Hennessy wrote:
"Having said all that, that room looks like a total nightmare acoustically - all that glass and a wooden floor will make for a very lively space. Of course it looks lovely, but a thick rug and some heavy curtains will do far more for the sound in that room than anything else. But I appreciate that can be easier said than done if trying to maintain domestic harmony!"

Indeed, this was mentioned back on the first page of the thread by Radioman and myself, post 8 or thereabouts.

[Bushbaby]

New stands applied and these are near in size to the original ones. The music sounds somewhat more aggressive being near to the ground. Yes, I also agree that the room is nor particularity brilliant with regards to any inner acoustic damping but we will have to live with this as this was how we planned it to be.

Best Regards


   

[Murphyv310]

The music sounds somewhat more aggressive being near to the ground.

Best Regards

Hi Rob.
No more AC-DC then, a switch to Enya on the cards

[Bushbaby]

Hi Trevor,
Definitely no AC-DC - mostly blues, jazz, jazz rock and classical music. Never more than half volume either.

Best Regards

[Diabolical Artificer]

They look better, some big thick curtains would help and some amps on the top or other junk would make them look smaller as would a few plants.

Andy.

[Bushbaby]

Oh dear, something appears to have happened! The output sound has suddenly become very aggressive and bright sounding - I will have a look at the amp and I know that I have got to rewire the speakers as both Andy and Trevor has indicated. I did continue to temporarily use the horrible huge Mission internal cable but it was horrendous to solder to small contacts.

Best Regards

[Murphyv310]

Can you explain what you mean by aggressive.
Has the bass and treble dropped? Had the mid range changed? Is this on both channels? Does the wife notice any change? Is your hearing aids working properly?
I'm being sarcastic but we need more info, even to the extent has the curtains been changed?

[Bushbaby]

Apologies, and I will endeavour to clarify. The speakers etc have not been moved and the system is still sitting as placed. The bass level appears to have dropped as has the midrange and treble has very much increased. No change to any of the output controls, the bass and treble are still set at 12 o'clock (neutral) on the amp. Where I have had the amp at about 50% volume which I had been using over the last week or so, the output is almost painful on the treble side (which I may have wrongly called 'aggressive') to listen to and I've had to turn the volume down.
I am aware that the room is not set up well for a hifi system but Angie and agreed that we wouldn't be putting up any thick curtains but blinds will be fitted. The floor will be left as is with no rugs etc. and we will have to live with this. However, the current change in sound is different from as it was a few days ago so I am wondering if anything has become faulty??

Best Regards

[Mark Hennessy]

What difference are you expecting to hear from changing wire?

Members here might not be aware that these speakers have been discussed in a couple of other forums:

https://pinkfishmedia.net/forum/threads/...le.185796/
https://www.diyaudio.com/community/threa...le.288599/

No rule against that, naturally, but multi-forum threads do get confusing when we don't know that the OP is receiving advice from multiple places.

Reading the DIY Audio thread, I see that you received a lot of advice about tweaking the crossover to suit the new drivers. Of course, this advice was remote, so we (nor the people giving it) have no way of knowing what effect it actually had.

But I also read (post #11) that you bought a measurement microphone!

In this and previous threads, I have stressed the importance of measurements. Ears might be the final arbiter, but measurements are absolutely essential. If anyone tells you otherwise, they simply don't realise how little they know about speaker design!

So how about you show us some measurements? Because until you do, everyone - myself included - is simply guessing. But at least I'm trying to help you from the perspective of someone who designs loudspeakers.

Which reminds me - no-on has commented on my explanation of the "reference axis" that I gave in post #30. Presumably because that went against the advice to lower your stands. I wouldn't dream of telling you to raise or lower your stands because I have no way of knowing how high your ears are when you sat down - and nor does anyone else on this forum. Hence my advice to ensure your ears are level with the reference axis, which was probably the tweeter originally, but who knows now that these speakers share literally only an enclosure with the original design. But with your measurement mic, you'll be able to take measurements to discover what the best listening height relative to the tweeter might be. That gives you actual data about the ideal height for your stands, based on science rather than aesthetics.

To the current problem, have you checked the frequency response of your amplifier? It's literally a 5 minute job.

It could have an intermittent fault. Have you exercised all the controls, in case they need cleaning. Likewise, does the fault affect all source equipment, hence narrowing it down to the amp or speakers? For the speakers to suddenly change their tonal balance to that extent, they either have a dry joint that (presumably?) affects both at once. You'd hear if the woofers had a fault like rubbing voicecoils.

If nothing else, have you tried swapping equipment with another system? I don't understand the reluctance to make use of the test gear you have, but in the absence of suitable test gear, we "test by substitution". It's sometimes a little inconvenient, but it might be easier in the first instance before dragging gear to the workshop.

It's really very frustrating. With no measurements, nor any sign that a logical, engineering-based approach is being employed here, I'm afraid we end up with threads containing little more than guessing and speculation - and leave me with the nagging impression that my detailed explanations and attempts to help (here and in previous threads and email conversations) are being ignored. At least tell me if my input isn't useful, or is not pitched at the right level, and I'll either butt out, or try to tailor my advice accordingly...

[Bushbaby]

Hi Mark
Again, I do apologise as I do go on numerous forums but I can image that other members do too.
Yes, I have completely forgotten that I do have a measurement microphone but having being away from home on numerous projects, its packed away somewhere and I will have to find it. Ok, I shall a) find the microphone and take some measurements and b) also check the amplifier.
As you have indicated, what is needed is factual info at this stage.

Best Regards