We’ve all heard that a turntable’s dust cover catches more than just dust; it can also act as a resonance trap that can negatively affect sound quality. A delicate instrument dealing specifically in vibration & resonance, the ultra-sensitive phono cartridge can transcribe unwanted resonance exacerbated by the dust cover. Audibly this can amount to boomy sonics, a bloated midrange, dynamic congestion and an overall lack of clarity & transients. In worst-case scenarios you’ll encounter actual acoustic feedback rendering your system unlistenable.

Pro-Ject Has Taken Measurements & the Results May Surprise You

To measure the effects of the dust cover, Pro-Ject HQ in Austria played various frequencies on speakers near an active turntable with the dust cover open, closed and removed entirely. They recorded the intensity of acoustic feedback penetration into the vinyl playback system. Components of the test looked like this…

  • Primary E turntable w/ Ortofon OM 5E moving magnet cartridge
  • Turntable RCA output connected to Phono Box MM phono preamp
  • Floorstanding speaker pair distanced 1m (3.28 ft) from the turntable
  • Tonearm lowered onto record, turntable motor OFF (record platter idle)
  • Various frequency test tones played through speakers
  • Measurements were taken from the Phono Box MM’s output

The graph below shows the resonance of the dust cover. Take note of the peak around 200Hz with the dustcover open (orange line). This is only 25dB less than the max signal  OM 5E can deliver! With the dust cover closed (green line), performance is actually slightly better and with the dustcover removed entirely (blue line) there are no discernible peaks in acoustic feedback.

Pro-Ject Audio Sytems Measures the Impact of Dust Covers on the Resonant Performance of Turntables

We Recommend Removing the Dust Cover When Playing Vinyl – Here’s why…

  • No Dust Cover – It’s no surprise that what you see above is the baseline performance the turntable has to offer: resonance-free playback behavior (at least as it pertains to the dust cover).
  • Dust Cover Open – This may come as a surprise since the common conception is that a closed dust cover performs unfavorably compared to an open one. In actuality, the reverse appears true! The open dust cover presents much more surface area to the medium that transports sound – the air – meaning it will catch and transfer more resonance.
  • Dust Cover Closed – As shown, a closed dust cover amounts to less resonance than an open one, but performance is still a far cry from a dust cover that’s removed entirely.