What are the frequency limits of a WiiM?

[guy48065]

A week ago I was demoed a pair of large speakers & one of the songs played--from CD--had several parts of the song where the woofers were pumping at about 3Hz. It couldn't be heard but it was visually striking. I've never seen anything like it and I left wondering if it was deliberately encoded onto the disc, or if there was something wrong with the system.

I couldn't reproduce it at home (I bought the same CD) but I doubt my entire signal path is DC-coupled.
In both my systems nearly everything now goes thru a WiiM. IF a source has content below 20Hz can a WiiM pass it on to the amp?

I tried running my CD/DVD analog out straight into my amp, thru only a passive volume control. No infrasonics were seen. I know my amp is rated -3dB at 3Hz so I think it would drive the speakers, if the CD player could output it.

 

[slartibartfast]

A week ago I was demoed a pair of large speakers & one of the songs played--from CD--had several parts of the song where the woofers were pumping at about 3Hz. It couldn't be heard but it was visually striking. I've never seen anything like it and I left wondering if it was deliberately encoded onto the disc, or if there was something wrong with the system.

I couldn't reproduce it at home (I bought the same CD) but I doubt my entire signal path is DC-coupled.
In both my systems nearly everything now goes thru a WiiM. IF a source has content below 20Hz can a WiiM pass it on to the amp?

I tried running my CD/DVD analog out straight into my amp, thru only a passive volume control. No infrasonics were seen. I know my amp is rated -3dB at 3Hz so I think it would drive the speakers, if the CD player could output it.

You could rip the CD to a file then open the file in Audacity to check the spectrum of the tracks.

 

[guy48065]

I'm pretty sure now the WiiM can process & output infrasonic frequencies.
As a quick test I used a function generator app I have on my phone & set a frequency sweep from 1Hz to 20Hz in a 10-second sine sweep. I then Bluetoothed that to the WiiM >> my old PS IV preamp >> Adcom GFA-5800 amp >> Thiel CS7 speakers. These old components output the sweep all the way down to 1Hz. I didn't try to measure any roll-off... Really didn't care... Just wanted to see if there was a lower limit to the WiiM and my system.

View attachment 20241223_190451.mp4

 

[guy48065]

I'd love to know if anyone else has seen infrasonic content on a commercial CD? Is it just a trick? Recording engineer showing off?

 

[guy48065]

You could rip the CD to a file then open the file in Audacity to check the spectrum of the tracks.

Never used Audacity.
How would I search for content below 20Hz?
On my PC I won't be able to see woofer movement--no real woofers there

 

[slartibartfast]

Never used Audacity.
How would I search for content below 20Hz?
On my PC I won't be able to see woofer movement--no real woofers there

Audacity can calculate and display the spectrum of the waveform so if there is anything below 20Hz you will see it.

 

[Valentino]

Well. It does play the 16.4 Hz organ pedal that opens Richard Strauss’ Also Sprach Zarathustra on the Deutsche Grammophon Original Source vinyl reissue of the Boston SO and William Steinberg recording from the early 1970s.
It also frightens my dog when I play Elektro Kardiogramm from Kraftwerk’s Tour de France Soundtracks (CD rip). I haven’t checked the actual frequencies on that album, but it is very good for finding loose items of furniture.

 

[574stereo]

Infrasonic information is often missed at mastering.

Whether you’ll see it as cone movement is also to do with the loading of your woofers. If they’re in a ported enclosure then yes, extreme infrasonics will result in cone movement. In a sealed box however the volume of air in the box will counter the motion of the driver at the very lowest frequencies.

 

[guy48065]

Infrasonic information is often missed at mastering.

Whether you’ll see it as cone movement is also to do with the loading of your woofers. If they’re in a ported enclosure then yes, extreme infrasonics will result in cone movement. In a sealed box however the volume of air in the box will counter the motion of the driver at the very lowest frequencies.

Where do these infrasonic "mistakes" come from in an all-digital mastered song?
I can understand it creeping into an analog production--but not digital.

 

[574stereo]

Where do these infrasonic "mistakes" come from in an all-digital mastered song?
I can understand it creeping into an analog production--but not digital.

It's not just to do with the mastering, there are a huge number of places infrasonics can creep in regardless of whether the process is analog or digital. If anything, it's arguably easier for these to slip through the net with digital production.

Very fast compressor settings often generate infrasonics, other dynamic processes too (gating, dynamic EQ even).
Synthesizers can generate insane infrasonics (approaching DC).
Low frequency saturation can generate intermodulation tones which are very low in frequency.

 

[guy48065]

Ok.
I think if you saw this, in this song, you might agree it was intentional.

I've seen the effect once or twice in a commercial. It's eye-catching.

 

[slartibartfast]

Ok.
I think if you saw this, in this song, you might agree it was intentional.

I've seen the effect once or twice in a commercial. It's eye-catching.

Unless I missed it you haven't said which song or CD you are talking about.