Chesty nasal sound

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Hi guys,

I'm hoping to get some advice on possible causes and remedies of a nasal / chesty quality from a center speaker.

It is a Legacy Audio center speaker that i got second-hand, supposed to have retailed at more than 1k new.. I had opened it up previously to add some foam and stuffing, it did help the problem slightly, however it is still rather obvious and unpleasent.

The enclosure is very solidly built 3/4 in MDF, with two shelf bracing (this is a regular sized MTM center speaker), using a pair of Vifa woofers and a tweeter. The crossover looked very well built, almost like a hand assembled DIY design, with quality inductors and capacitors.

Guess what i'm trying to say is that the nasal / chesty sound is definitely not because of a poorly constructed, resonant cabinet, crappy drivers and a cheap crossover.

If so, what could be the cause, and how do i begin to try and fix it? I will try to get pictures and specs posted.

Thanks!!
 
Hmm, not broken or faulty, just that vocals in movies and 5.1 audio have a chesty and nasal colouration. Does not sound neutral and natural, as in a real voice.

I would imagine it to be related to a uneven or frequency response, as if a certain frequency is particularly prominent.

Could this be due to a particular driver resonance not filtered out using a notch filter?
 
Did you try reversing the phase at the speaker terminals ( of the center channel )? If it's causing a bass hump it should reduce this. If it now sounds OK just leave it or introduce an 'informed' bass roll off with normal polarity!
 
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It's just on top of the console infront of the LCD tv. Previously it lived on top of a rear projection tv. Same problem. Don't it's due to location.

Will try the polarity. I thought the cancellation generally results in no bass.

Do woofers need notch filters? In what circumstances?
 
I'm hoping to get some advice on possible causes and remedies of a nasal / chesty quality from a center speaker.

'Chesty' = pronounced mid-bass (~128-896 Hz), so a higher F3/lower Q is normally the fix.

'Nasal' = mids distortion (~896-2560 Hz), so depending on the driver's/XO's combined response, raising F3 may solve it all or you may need to also insert some amount of 'BBC dip' to tonally balance it all out with the trade-off being potentially some loss of the high speech intelligibility that the center is mainly there for.

GM
 
What are you using to drive the speaker? Legacy Audio center speakers tend to have low nominal impedance ratings. They may present a difficult load to some amplifiers, something which can affect the sound quality of the speaker.

Is your speaker a twin-ported bass-reflex design, as with other Legacy Audio center speakers? If so, you can try experimenting with plugging the ports with open cell foam or poly-fill, as others on this forum have suggested. This may help with the mid-bass emphasis your experiencing. You can refer to the thread http://www.diyaudio.com/forums/multi-way/161886-bass-reflex-aperiodic-conversion.html for a discussion on this subject.
 
It's just on top of the console infront of the LCD tv. Previously it lived on top of a rear projection tv. Same problem. Don't it's due to location.

Will try the polarity. I thought the cancellation generally results in no bass.

Do woofers need notch filters? In what circumstances?

You're probably getting a mid-bass boost from the furniture and previously the RPTV. Front projection with an acoustically transparent screen and good speaker placement is the ideal solution, although you'll spend less money on a shelving high-pass filter or AV receiver with room correction.

Put the speaker on a stand well away from any walls or furniture and listen to it. Assuming the problem goes away you can then decide how much time and money to put into the fix.
 
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