Record Player sounds muffled

  • 5 August 2018
  • 5 replies
  • 6617 views

Hey, have a full home set up (playbar + sub, 1, 3, 5) plus record player as a line in input through a preamp and then into a connect. Recently the quality of sound from records has significantly diminished. It sort of sounds like the sound is muffled, almost like it’s under water. It’s like there’s far too much bass, but even when I use the room settings and turn treble up and bass way down it’s still average. It seems to have happened after we moved house recently but it also coincided with a sonos Update so not really sure what the root cause could be. But playing the same music through Spotify sounds far better than vinyl. Diagnostics number 1676025177

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5 replies

Sounds like the phono preamp got turned off or is not connected. If internal to the turntable, switch it on. If external, it needs to be connected between the turntable and Sonos.
Check the turntable's stylus and tracking force.
Further food for thought: Some high end Phono Preamps offer a "Load" switch. Magnetic cartridges usually need a load of 47K, Moving Coil cartridges need a much lower value. If you are using a standard Magnetic cartridge and the load is switched to 1K or even 100 Ohms, highs from the Magnetic cartridge will suffer.

In your new house, check the air conditioning air paths. Phono Cartridges are very temperature sensitive. If you have cold air blowing on the cartridge, the highs will suffer. (been there, done that)

Also, don't extend the wires between the turntable and Phono Preamp. Poor choice of cable can roll off the highs.
It seems to have happened after we moved house recently but it also coincided with a sonos Update so not really sure what the root cause could be.
Almost certainly due to the former, and a check of the mechanical attributes of the turntable suggested already seems to be the first step. Turntables have to be moved like babies.
Phono preamps are a special class of device. Humans are more sensitive to high frequency noise, we don't care as much about low frequency noise. The record manufacturing process adds a certain amount of high frequency noise. In an effort to minimize this annoyance, the high frequencies are exaggerated during manufacturing, then highs are reduced by a complimentary process during playback. The playback equalization reduces all high frequency content, signal and noise, but the signal has been boosted in anticipation of this playback reduction. The overall result is "noise reduction". This is a standard process often referred to as "RIAA equalization". One might also read about this as "pre-emphasis" and "de-emphasis"

For this discussion, if the RIAA playback equalization is missing, the highs will be exaggerated, not reduced.