Sierra2 port chuffing

[SAFETYpin]

I've been away from home for work about 1 week and the first thing I did when I got home was fire up the HiFi. To my horror the 2nd track I listened to had this odd noise. I initially thought something was rattling on a shelf but it seems to be coming from the ports. I don't really recall hearing it before I left but I'm getting significant noise from the ports. I'm pretty sure it's due to the air turbulence of the port which I believe is text book "Chuffing"?

The track was "It Could Be Sweet" by Portishead (https://play.spotify.com/track/1cpnpMvnvmdy3hzYgd5oo9), which is very bass centric. I don't really notice it with other tracks.

In total disclosure, the day before I left I was doing some measurements and messing with subwoofer phase. I had played Pink noise and set volume to ~85db. I then played a 50hz sine and adjusted the sub phase until reading the highest SPL at the listening position. I definitely heard significant port noise while performing my measurement but I kind of just wrote it off due to the sine wave.

I also spent some time setting a PEQ on the sub to help tame the room mode @ 55hz, I unfortunately have no way of doing anything for the mains at the moment.

All of my amp's tone controls are bypassed via a "pure" switch on the amp.

I didn't really get a chance to evaluate anything I was doing before having to leave town.

Anyone else able to evaluate this track and notice anything....?
Could I have damaged something by playing a sine wave for an extended period?
Could the room mode be contributing to the noise?

Larger (http://i.imgur.com/ekGCCoX.jpg)
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[sharkman]

I don't have that track, but if you're getting odd noises like that I'd suggest you need to back it off a little.
My Sierra 2's are driven by a Parasound Halo A21 with 250 wpc on tap. I've never heard any kind of port noise. These are quality speakers, but every speaker has its limits.

[curtis]

First...are you sure it isn't some anomaly in the track itself...bad recording?

Second...are you sure the noise is coming from the port? The port on the Sierra-2 is quite large and flared, hard to believe it can be chuffed without turning the volume up very high. I demo'd a pair at Ascend, no sub, to some crazy high levels with The Sheffield Lab: Drum and Track disc with no sign of chuffing or distress.

When driven full-range, I have not heard issues like that from my Sierra-2's.

Room node at 55hz? You should not fix nulls by EQ, only peaks. If you turned the PEQ up at 55hz, I bet that is your problem. Oops...nevermind, that was for your sub only.

I'm assuming you are crossing over to the sub at 50hz...why so low? I cross at 80hz.

[curtis]

OK...I played the track off of Tidal.

Definitely moves air, but no chuffing...I had it pretty loud at full-range.

I am wondering if your room is accentuating the frequency and making it sound bad...like chuffing.

[SAFETYpin]

My Sierra 2's are driven by a Parasound Halo A21 with 250 wpc on tap. I've never heard any kind of port noise.

I don't have any where near that amount of power on tap, 100wpc @ 8ohms Yamaha A-S801.
Maybe I'm not familiar with what real chuff is, but if I put my fingers in the port the noise changes or goes away.


First...are you sure it isn't some anomaly in the track itself...bad recording?
Second...are you sure the noise is coming from the port?
Room node at 55hz? You should not fix nulls by EQ, only peaks.
I'm assuming you are crossing over to the sub at 50hz...why so low? I cross at 80hz.

It might just be something weird with that track. I added a link to spotify incase anyone wanted to check it out.

I actually have the crossover set to max but have the LPF on the sub set to 50hz/24db Rythmik F12. 80hz seems pretty high unless you have some sort of HPF. Are you running full range with your Sierra2? I figure the sub is just there to fill in where the Sierras start to lay down.

[curtis]

I actually have the crossover set to max but have the LPF on the sub set to 50hz/24db Rythmik F12. 80hz seems pretty high unless you have some sort of HPF. Are you running full range with your Sierra2? I figure the sub is just there to fill in where the Sierras start to lay down.
Yeah...I am running a HP (but did fullrange to test the track). No need to stress the Sierra's woofer/low end if you don't have too...and bass is cleaner from the Rythmik.

[curtis]

Maybe there is something different with the Spotify track.

That Yamaha is nice...feed it some high quality source. :)

[SAFETYpin]

That Yamaha is nice...feed it some high quality source. :)

I can't hear a difference between 320kbps Vorbis and FLAC, so I'm not terrible worried about it.

I was able to capture the sound on my phone. YouTube (https://youtu.be/hFnQXe6dd5c) This was recorded roughly 3-4in. away from the port and off to the side of it and at ~2:15 in the track. Playback volume was peaking around 93db according to an app on my phone, I didn't bother getting the measurement mic out.

That flutter/port noise is pretty prominent on this track. The phone did a good job picking up the noise, IMO. I'm getting this on both speakers so if it is damaged somehow, I managed to do it to both.

[curtis]

That certainly doesn't sound like port noise or what I hear from my speakers.

Can you reproduce something like it with other music?

93db peaks are not extremely loud...but the SPL/FR apps on the iPhone are not accurate...although for this application it should be fine.

[SAFETYpin]

I can recreate it with REW and a sine wave, I don't notice it in other tracks as much. I was incorrect at the spl levels I was using during my phase adjustment. It was probably closer to 90db with pink noise and then playing a 50hz sine. If I recreate this scenario I can start to hear the noise at ~63-60hz but it gets louder as I drop the frequency, and starts rolling off ~45hz.

50hz sine 90db video (https://youtu.be/1Tv04pKPjuQ)
Hand near port 50hz sine (https://youtu.be/dsApGcZmhz8)

Another track I notice it in.... "Never End Land" by Infected Mushroom (spotify:track:3FIE2YHX3OkqnWHxCBBoiU) very noisy around 1:10

[curtis]

Time to call Ascend...or hopefully Dave will see this post.

How loud are you testing with the sine waves to get the noise? Sine waves are very demanding.

[SAFETYpin]

Time to call Ascend...or hopefully Dave will see this post.

How loud are you testing with the sine waves to get the noise? Sine waves are very demanding.

I'm setting volume to 90db with pink noise and then playing a 50hz sine. Actual measured volume during the 50hz sine is a higher than with the pink noise about 96db.

[sharkman]

Well that's an odd noise for sure. Are you getting a lot of woofer movement during those noise events?

I just remembered that I have my Sierras crossed over to a sub at 80 Hz, so I'm no help! But originally I did push the volume when I first put them in the 2 channel system and had no issues at that time.

[Beave]

Wait a second....the Yamaha integrated amp you are using doesn't have bass management, does it?

In other words, it doesn't have a high-pass filter (or a selectable or variable) high-pass filter for the mains output.

Are you using an external EQ device with a high-pass filter?

Otherwise you are still feeding a full-bandwidth signal to the Sierra 2's.

[Beave]

Just watched your videos. Something seems off for sure. That port noise is weird.

Do the speakers sound ok otherwise when playing music (with no subwoofer playing)?

Do both speakers make the same noise (for the same test signal)?

[RicardoJoa]

Make sure is not the damping material that is vibrating inside the cabinet

[theophile]

Time to call Ascend...or hopefully Dave will see this post.

How loud are you testing with the sine waves to get the noise? Sine waves are very demanding.

Agreed...Call Ascend!

My Sierra 1 NrT's playing warble 50 Hz, then 40 Hz test tones have no audible port noises, unless I stick my hand into the ports during the test playback at substantial volumes (95+db).

The S2's shouldn't be either!? Anyway, during this audible port chuffing, what are your S2 cone travel excursions looking like?

Ted

[SAFETYpin]

Wait a second....the Yamaha integrated amp you are using doesn't have bass management, does it?

Are you using an external EQ device with a high-pass filter?

Otherwise you are still feeding a full-bandwidth signal to the Sierra 2's.

Correct I'm not running any kind of HPF to my mains, full range only.


Anyway, during this audible port chuffing, what are your S2 cone travel excursions looking like?

Ted

You can tell they're moving because they appear out of focus but there's not much extension during the sine wave. Outside of this noise, they still sound good, and both speakers are behaving this way.

As someone else suggested it could be dampening material moving...

[davef]

In total disclosure, the day before I left I was doing some measurements and messing with subwoofer phase. I had played Pink noise and set volume to ~85db. I then played a 50hz sine and adjusted the sub phase until reading the highest SPL at the listening position. I definitely heard significant port noise while performing my measurement but I kind of just wrote it off due to the sine wave.

This was really a bad idea... Sine Waves are not music, they are steady state and heat up voice coils very quickly. 50Hz also happens to be where the port is tuned and as such, this is where the woofer has minimal movement so the voice coil has the least amount of cooling (nearly all output at this frequency is from the rear port)

With setting the level to 85dB using pink noise, it is highly likely that 50Hz could be -10dB or even more depending on your room modes. If you were measuring SPL at 10 feet back, you were hitting the speakers with a 100watt 50Hz sine wave. Frankly, I am surprised the woofer coils didn't completely burn up.

It is highly likely you damaged the woofers but please answer these questions.

1. How far back were you sitting when you measured the SPL?
2. What did you use to measure the SPL and what weighting?
3. When you hear this noise, is it only this particular song?
4. Are you running the speakers full range?
5. Did you send the sine wave to both speakers at the same time or one speaker at a time?
6. What amp or receiver are you using?

And most importantly -- please stop hitting the speakers with sine waves :)

Also, please feel free to send me an email directly.

Thanks in advance!

[SAFETYpin]

This was really a bad idea... Sine Waves are not music, they are steady state and heat up voice coils very quickly. 50Hz also happens to be where the port is tuned and as such, this is where the woofer has minimal movement so the voice coil has the least amount of cooling (nearly all output at this frequency is from the rear port)

With setting the level to 85dB using pink noise, it is highly likely that 50Hz could be -10dB or even more depending on your room modes. If you were measuring SPL at 10 feet back, you were hitting the speakers with a 100watt 50Hz sine wave. Frankly, I am surprised the woofer coils didn't completely burn up.

It is highly likely you damaged the woofers but please answer these questions.

1. How far back were you sitting when you measured the SPL?
2. What did you use to measure the SPL and what weighting?
3. When you hear this noise, is it only this particular song?
4. Are you running the speakers full range?
5. Did you send the sine wave to both speakers at the same time or one speaker at a time?
6. What amp or receiver are you using?

And most importantly -- please stop hitting the speakers with sine waves :)

Also, please feel free to send me an email directly.

Thanks in advance!

OH NO!!!!

1. ~8ft to the mic, it's a pretty small room but does have two open doorways to the rest of the house.
2. Umik-1 Z weighting as it's what REW recommended with the USB mic
3. I've noticed this in two tracks
4. Speakers are full range, I don't have any type of HPF with my amp.
5. I don't recall, i've probably done both.
6. Yamaha A-S801 http://usa.yamaha.com/products/audio-visual/hifi-components/amps/a-s801/

What is my mistake going to cost me, approximately?

[davef]

Just a few more questions...

When you hear the port noise, at what SPL? Also, when you lower the volume level, does the port noise decrease as well?

Do you hear the port noise at your listening position or only when you are behind the speakers?

[SAFETYpin]

Just a few more questions...

When you hear the port noise, at what SPL? Also, when you lower the volume level, does the port noise decrease as well?

Do you hear the port noise at your listening position or only when you are behind the speakers?

I can hear the noise during the two tracks I listed in the listening position at ~88-90db. The noise does decrease when I turn down the volume.

[davef]

I can hear the noise during the two tracks I listed in the listening position at ~88-90db. The noise does decrease when I turn down the volume.


I can hear the noise during the two tracks I listed in the listening position at ~88-90db. The noise does decrease when I turn down the volume.

After listening a bit more carefully, it sounds more like distortion than port noise, but I really can't be sure without a proper evaluation. As mentioned, hitting the speakers with sine waves at these volume levels is not recommended. My advice at this point would be to send the pair back to us for complete evaluation. Additionally, deep bass tracks at high volume levels will certainly cause port noise and/or mechanical noise from the woofer reaching its excursion limits.

It is also possible you are reaching the limits of your amp's available power. Best to let us evaluate the pair at this point...

[SAFETYpin]

Thanks Dave. I'm currently out of town for work again, but I'll be in touch when i get back home.

[SAFETYpin]

Thought I'd stop back in and say my Sierras received a clean bill of health from Dave, thanks for everyones help.

[goldark]

What was the issue causing the noise?

[SAFETYpin]

I believe Dave's opinion is its port noise. Due to a lack of bass management on my amp, the speakers are receiving full range. These specific tracks have a lot of content in a frequency below the tuning of the speaker port. Perhaps Dave will step back in and more eloquently explain.

My only real solutions are to avoid the tracks at the volumes I was playing them OR try to get some bass management in my system and only send 60hz and above to the Sierras.

I think it's nearly impossible to get these features in my current amp so I suppose I'll have to start shopping for a replacement.

So the big question is stick with an integrated amp or go with an AVR?

I never plan on having a 5.1 as I don't have the space to set it up, but most of the AVRs have the feature I need. BUT I really like the classic looks of the Yamaha integrated amps. If I step up to an A-S1100 I'll get preamp outs/main ins and be able to setup a DSP to get the features I need. Plus I've been lusting after some V.U. meters.

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They're just so expensive, bah....

[N Boros]

Another fix is to get a subwoofer with speaker level inputs. Let the sub do the bass management and improve your overall experience by filling in those largely missing bottom two octaves. Sounds like a win-win experience to me.

[curtis]

Another fix is to get a subwoofer with speaker level inputs. Let the sub do the bass management and improve your overall experience by filling in those largely missing bottom two octaves. Sounds like a win-win experience to me.
He's got an F12...perhaps that will do the trick?

[curtis]

Does your integrated amp have a tape loop/monitor. If so, I believe you can use the Rythmik's crossover and RCA input/output and the loop/monitor to achieve bass management.

I am just thinking out loud here...

[sludgeogre]

Or go separates with Emotiva. The XSP-1 has an amazing bass management system and it is $1k. Get whatever external amp you want or splurge and get an XPA-2 Gen 3. The Gen 2's are out there for pretty cheap used as well.

https://emotiva.com/products/pres-and-pros/xsp-1

[davef]

I believe Dave's opinion is its port noise. Due to a lack of bass management on my amp, the speakers are receiving full range. These specific tracks have a lot of content in a frequency below the tuning of the speaker port.

Yes, it is just port noise. Deep bass content (below port tune frequency) at even moderate volume levels will always cause port noise in any ported speaker.

[SAFETYpin]

Just to continue the conversation some. I pulled the trigger and purchased a Yamaha A-S2000, this will allow me to run a DSP and setup a HPF to the Sierra2s. Now I need to purchase a DSP and a DAC.

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Anyone that's walked this path before care to share what hardware they purchased?

[sludgeogre]

I've researched using a DSP more than once, but never did it. The MiniDSP 2x4 is appearing all over the place, I've even heard that some companies are looking to build them right into their products. It really offers the best bass management and DSP option available by far, especially at the crazy low price they sell it for. They also have a very active and informative community.

https://www.minidsp.com/products/minidsp-in-a-box/minidsp-2x4

[SAFETYpin]

Well I purchased a Schiit Modi 2 Uber to replace the loss of the built in DAC of my Yamaha A-S801 and a MiniDSP 2x4HD.

[sludgeogre]

Well I purchased a Schiit Modi 2 Uber to replace the loss of the built in DAC of my Yamaha A-S801 and a MiniDSP 2x4HD.

Right on! Great choice! I have the original Modi and it was my first step into audiophilia, I still remember being so amazed at how great it sounded.

Have fun with the MiniDSP, I haven't used one before, but I have heard many great results. You will have to spend some time tweaking with it, but just having the low pass filter alone makes it worth it. Eventually you may want to buy a UMIK-1 microphone and play around with the DSP filters a little bit.

Hope you enjoy it.

[SAFETYpin]

Eventually you may want to buy a UMIK-1 microphone and play around with the DSP filters a little bit.

Hope you enjoy it.

I already have the UMIK-1 so this just continues the trip down the rabbit hole.

[sludgeogre]

I already have the UMIK-1 so this just continues the trip down the rabbit hole.

Nice! You are well equipped for the journey. Should be a lot of fun!

[SAFETYpin]

Well I think I messed up again!!!! I'm reviewing the A-S2000 Instructions and it sounds like I cannot run the Preamp out and back into the Main In..... I just spent a pile of cash and I'm still not going to be able to do what I want... I'm very frustrated....!!!

Yamaha A-S2000 Manual (http://download.yamaha.com/api/asset/file/?language=en&site=au.yamaha.com&asset_id=23095)

From the manual
• Switch to the MAIN DIRECT position to select the component
connected to the MAIN IN jacks. When MAIN DIRECT is
selected as the input source, no signals are output at the PRE
OUT, REC, and PHONES jacks.

[sludgeogre]

Yeah I don't know of any preamp or integrated that you can go out and back in from, unless you do use one with a tape loop thing meant for recording I guess?. I would suggest you spend one last $50 and pick up a Schiit SYS passive preamp, then you can go from your Modi 2U DAC, to the SYS Preamp, then the MiniDSP unit, then into your A-S2000 and subwoofer. That'll get it done.

[SAFETYpin]

I guess I assumed it was a normal feature as my buddies 40 year old Marantz 2270 has it. BAH!!
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[sludgeogre]

I guess I assumed it was a normal feature as my buddies 40 year old Marantz 2270 has it. BAH!!
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Yeah, my Dad's very old McIntosh C26 preamp has a tape loop on it for recording, same kind of thing (I think...). It also has a weird center channel mix thing that it does. It's a neat preamp.

[SAFETYpin]

Well I purchased the Schiit SYS too, but I'm really not happy about it. Seems like such a huge waste to not use the Preamp section of the Yamaha, also I lose remote control for volume duties... I should have just bought an AVR....

[curtis]

Well I purchased the Schiit SYS too, but I'm really not happy about it. Seems like such a huge waste to not use the Preamp section of the Yamaha, also I lose remote control for volume duties... I should have just bought an AVR....
I can understand your frustration, and I am not going to advocate that you spend more money.

That said, I think your best solution, if you do not want to do an AVR, is separate pre-amp/amp combo with the miniDSP in between. Although, I might be stating the obvious at this point...if so, I apologize.

[sludgeogre]

I can understand your frustration, and I am not going to advocate that you spend more money.

That said, I think your best solution, if you do not want to do an AVR, is separate pre-amp/amp combo with the miniDSP in between. Although, I might be stating the obvious at this point...if so, I apologize.

Yeah, the integrated amp is what makes this difficult. If you can return the Yamaha and go with separates then you won't have this problem. Schiit will hopefully be making preamps with remote controls very soon as well, but yeah, more money.

[SAFETYpin]

More follow up.

The MiniDSP 2x4 HD has an IR sensor and can also function as the DAC and PREAMP. This significantly simplifies the signal chain and I don't need the Schiit Modi or SYS, plus I retain remote control functionality :o. Setting up a HPF for the Mains at the Sub Xover (60hz) really improved the low freq clarity, and completely fixed the objectionable port noise I was getting in the select tracks from my original post. Next up I'll start learning about Room Correction and the Do/Don'ts of that rabbit hole.

I did try to use the Modi/SYS with the MiniDSP but the volume control of the SYS was really odd. At low volumes I would just get high frequencies and as I increased the volume the frequency response would begin to balance out. This made normal TV watching or any listening below a "Loud" volume very irritating. I don't know if this is just a normal characteristic of a Passive PRE amp or caused by something else in my signal chain.

[sludgeogre]

More follow up.

The MiniDSP 2x4 HD has an IR sensor and can also function as the DAC and PREAMP. This significantly simplifies the signal chain and I don't need the Schiit Modi or SYS, plus I retain remote control functionality :o. Setting up a HPF for the Mains at the Sub Xover (60hz) really improved the low freq clarity, and completely fixed the objectionable port noise I was getting in the select tracks from my original post. Next up I'll start learning about Room Correction and the Do/Don'ts of that rabbit hole.

I did try to use the Modi/SYS with the MiniDSP but the volume control of the SYS was really odd. At low volumes I would just get high frequencies and as I increased the volume the frequency response would begin to balance out. This made normal TV watching or any listening below a "Loud" volume very irritating. I don't know if this is just a normal characteristic of a Passive PRE amp or caused by something else in my signal chain.

That is great news! Didn't realize that the MiniDSP would sound that great as a DAC as well. Not sure why you're getting that issue with the SYS, might be due to a lower line level that it is designed for? Anyhow, maybe you can just return the Schiit gear and spend the extra cash on more music :)