Sierra2 port chuffing

[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...s/amps/a-s801/

What is my mistake going to cost me, approximately?