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Do all speakers suffer from port noise?

Mohsin

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Jul 26, 2008
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Yesterday I was listening to my monitor audio RX1 with a nad c326bee. I had the volume at just under 9 o'clock which is about as loud as I ever go with the nad. I was playing flo-rida (I know it's not to everyone's taste) and in one of the tracks when the bass dropped I could hear a funny noise as I wasn't standing far from the speakers. I decided to investigate and found that the noise was from the bass port. It was a sort of chuffing noise. It was only noticeable on the very bass heavy tracks and the nad seemed to make it more obvious then the marantz I normally use. I also have a pair of MA BX2 but as they are front ported it's probably less likely that I have noticed the port noise. Is this common in most bookshelf speakers when trying to push too much air around?

Mo
 

stavvy

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Jul 11, 2013
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I notice quite a difference in bass depending on how well my speakers are supported - originally had the spikes on the bottom of the stands going into silicone feet so as to not scratch the laminate flooring. Then one day I removed the silicone and just had the spikes going directly to the floor. Did not like the sound at all! Was surprise at how much difference it made really. Quickly put the silicone feet back on and the bass blended into the music much better.

ps my speakers are also bookshelves, B&W 685s
 

lindsayt

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Apr 8, 2011
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Sealed box speakers and open baffles don't suffer from port chuffing.

From a port chuffing / bass quality point of view, ported speakers are ubiquitous amongst modern designs.
 

sublime

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May 14, 2014
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someone correct me if I'm wrong but - the air pressure in the cabinet is changing as the driver moves in and out (like a pump) and the chuffing is the draft coming out of the port caused by the changes in cabinet pressure. I have curved edges on my ports and haven't in 15 years noticed any chuffing (not on the speaker ports anyway:)
 

Mohsin

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Jul 26, 2008
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Sublime, my understanding of the this is exactly as you have described it. I know the RX1 have a small cabinet so not much space internally for the air to move around before it gets out the port. This would also be more evident depending on the type of music you listen to. I hadn't noticed it in the month I have had these speakers until yesterday.

Mo
 

matt49

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Apr 7, 2013
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You can reduce chuffing by sticking some rolled up foam in the ports. Obviously this will also have an impact on bass response in general: you might not like it.

Matt
 

lindsayt

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Apr 8, 2011
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Vladimir said:
This is why B&W has the flared and dimpled port aka flowport (flo-port).
This may reduce chuffing but it doesn't stop their PM1 model from having a ridiculous amount of bass distortion at generous volumes.
 

Vladimir

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Dec 26, 2013
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lindsayt said:
Vladimir said:
This is why B&W has the flared and dimpled port aka flowport (flo-port).
This may reduce chuffing but it doesn't stop their PM1 model from having a ridiculous amount of bass distortion at generous volumes.
For that you buy speakers with bigger drivers. :grin:

BTW when I stand behind my CM1s at generous volumes, there is mindblowingly heavy bombardment of air and sound, like artilery. I never felt that much compression with bigger speakers and no chuffing whatsoever. Logic tells me that smaller cabinets should suffer more from port noise than bigger ones because of the compression inside the chamber.
 

nopiano

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Feb 15, 2009
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Mo, I think you need to turn the volume down if it that obvious! However, a different amplifier might control the speaker better but I couldn't say which. Or, controversially, biwiring might make a difference, but try before you buy.
 

Mohsin

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Jul 26, 2008
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Ok I just tried the same track on a few other speakers all with the exact same results. I tried the MA BX2 the Q Acoustics 1020 and Dali Zensor 1 and if anything the RX1's probably suffered the least. I was quite surprised I hadn't picked up on this before. I also tried plugging the ports and this reduced the chuffing by about 80% but I couldn't leave these in as they just made the speakers sound without any depth especially at lower volumes.

The track I am referring to is from Flo-rida's album Roots. It's track no 4 (Shone) and there is a big bass drop from about 3:20. If anyone has spotify or access to this track while I understand it may not be your type of music but give it a go to see how your speakers behave.

Mo
 

Mohsin

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Jul 26, 2008
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Thanks for your reply. I am very happy with these speakers and had extensively tried them. As I mention it's only now that I've managed to find a track that shows there short comings. I have tried bi wiring but couldn't hear any difference.

Mo
 

Neptune_Twilight

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Apr 14, 2014
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I've never heard port noise from my RX's but I don't often play them loud, but my son has a pair of RX8's bi-amped & recently I could feel the air blowing on my face coming from front the port as he does turn the wick up, and that was a fair distance away.
 

davedotco

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Apr 24, 2013
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Interesting.

We have discussed excessive movement in bass cones before, this is a feature of reflex (ported) enclosures and is caused by the loading on the cone reducing to a minimum one octave below the resonant frequency of the speaker system, ie for a speaker tuned to 60 hz, there will be minimal loading at 30 hz.

For much music there is not that much going on at this frequency, but some modern recordings might well have considerable output at these frequencies. Given the lack of loading on the cone, even a modest amount of sub bass will make the cone move a long way, the more it moves the more it pressurises the air in the enclosure and the more the air moves in the port.

If these frequencies are important to you, the simple answer is to use a sub for sub bass and find a way to limit the low bass to the main speakers.
 

matt49

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Apr 7, 2013
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davedotco said:
If these frequencies are important to you, the simple answer is to use a sub for sub bass and find a way to limit the low bass to the main speakers.
Or as I said above: "put a sock in it".

Matt
 

davedotco

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Apr 24, 2013
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matt49 said:
davedotco said:
If these frequencies are important to you, the simple answer is to use a sub for sub bass and find a way to limit the low bass to the main speakers.
Or as I said above: "put a sock in it".

Matt
I thought you were being literal, ie plugging the port with a sock......... :doh:

Just a passing thought, did you ever get to the bottom of the bass issues you had with the SFs? Using JRiver maybe you could have 'notched out' the offending frequency, would have been interesting to find out what frequency was causing the problem.
 

Mohsin

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Jul 26, 2008
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I had the RX2 for a little while and I can't imagine them suffering with this problem as they are a big bookshelf speaker. The internal volume must be close to twice that of the RX1's.

Mo
 

lindsayt

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Apr 8, 2011
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Dave how many frequency spectrum charts do I need to post on this forum before you stop saying that there's not much going on at 30hz to 60hz in most music?

Here's a frequency spectrum chart of Suzanne Vega's Solitude Standing, vinyl version.



It's a 27 year old recording with more going on at 30 to 60 hz than at any frequency above 520 hz.

Where did you get the notion from that there's not much going on at 30 to 60hz with most music?
 

Vladimir

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Dec 26, 2013
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lindsayt said:
Dave how many frequency spectrum charts do I need to post on this forum before you stop saying that there's not much going on at 30hz to 60hz in most music?

Here's a frequency spectrum chart of Suzanne Vega's Solitude Standing, vinyl version.



It's a 27 year old recording with more going on at 30 to 60 hz than at any frequency above 520 hz.

Where did you get the notion from that there's not much going on at 30 to 60hz with most music?
I think what he meant going on as in musical details. Under 60Hz there isn't even stereo a lot of the time, just ploding monobass.
 

matt49

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Apr 7, 2013
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davedotco said:
matt49 said:
Or as I said above: "put a sock in it".

Matt
I thought you were being literal, ie plugging the port with a sock......... :doh:

Just a passing thought, did you ever get to the bottom of the bass issues you had with the SFs? Using JRiver maybe you could have 'notched out' the offending frequency, would have been interesting to find out what frequency was causing the problem.
I did literally put a sock in the bass ports, which solved the chuffing and was fine up to a point, but I realized it had no future. I would have needed to get a sub to reconstitute the bass but that would have been far too complicated and almost certainly a route to dissatisfaction.

And then I bought the Martin Logans and put the SFs in store. (I made a desultory attempt to sell them, but I do love them dearly.)

Everything is in flux at the moment. We're still trying to move house. The SFs may return in a future elegant living room. Maybe with Devialet SAM treatment. That would be very interesting ...

Matt
 

andyjm

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Jul 20, 2012
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lindsayt said:
Dave how many frequency spectrum charts do I need to post on this forum before you stop saying that there's not much going on at 30hz to 60hz in most music?

Here's a frequency spectrum chart of Suzanne Vega's Solitude Standing, vinyl version.



It's a 27 year old recording with more going on at 30 to 60 hz than at any frequency above 520 hz.

Where did you get the notion from that there's not much going on at 30 to 60hz with most music?
Hmmn. Do you have an equivalent plot of the CD?

One of the problems with RIAA pre-emph / de-emph is the tendency to boost all LF noise, be it bearing rumble, vinyl surface noise, or LF feedback from the speakers.

It is possible that your plot has more to do with the limitations of vinyl than then frequency content of the original recording.
 

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