Frequency question

horse

There's something fairly fundamental I don't understand - not sure if it relates to EQ, frequency response or something else. Hope somebody can help explain, or point me in the right direction:

My 5 yr old lcd TV has fairly crap speakers, and certainly doesn't put out much bass. When I hear music on a tv programme, I can often clearly hear the notes that the bass is playing, even though they don't sound 'deep'.

That doesn't seem to happen with hi-fi though - eg I have a pair of decent quality speakers which don't go very low, and on lower notes I lose the sense of what notes the bass is actually playing. Is the tv audio processed before it is broadcast to somehow squash the bass up into a narrower range of mid frequencies / if so how does that work?

I'm partly interested because it seems to relate to recording production technique. For this month's riff of the month I recorded a deep drum sound - sounded great through headphones, monitors and hi-fi. When I played it on a laptop that deep drum sounded more like a rim-shot click - lost all the depth, and the bass guitar disappeared completely, so I'm guessing there must be a way to make that drum sound still sound 'low' even on crap laptop speakers? Is it just a case of listening through a greater range of speakers when mixing / EQ'ing?

mart

Sounds logical. The sound of the bass actually consists of some low frequencies that give the sense of depth, together with higher frequency overtones that give more definition. What are you hearing on the TV is precisely what you'd expect from that. I'm not quite so sure what's going on with your hifi - that sounds like he treble content is being taken out somewhere.

Drew_TNBD

TV audio is compressed to reduce dynamic range, that could be one reason. Another could be that your TV speakers are ported whereas your hifi ones are not, and that would explain the difference - at least part of it too.

horse

Cheers guys. If there isn't some production trick I'm missing then I suppose I just might not be comparing like with like, and all I'm noticing is the difference in frequency profiles between say a double bass vs bass on contemporary pop?

Nomad

Run the TV sound through the hi-fi and switch between the two to make a proper comparison.

mike257

This is also a large part of why it's recommended to check your mixes on multiple playback systems and to get to know how these systems sound. If you know and understand how commercial mixes sound on your hifi then you've got a point of reference for checking your own, same with the TV speakers.

Cacofonix

Compression can boost certain frequencies if they sit low in the mix, and a good compressor can even out a number of different frequencies, but that won't cut through a muddy mix.

But a good mixing engineer, (and they will be good on the TV channels) will attenuate crossover frequencies to make sure that the instrument that he wants to be clear sits in the space properly.  For eg taking out the kick in the 250-800 Hz area will reduce mud, and impliedly (though not in fact) increase the bass level.

I once tried out for a band that wanted a second guitarist, because their guitar sound wouldn't cut through.

Trouble was the bassist was the band leader, and he wanted his instrument to sound on all frequencies.  The singer was really quite good, and so it was obvious she needed to take over some of the mix, and the guitarist needed to be in there somewhere, and guitar and voice sit in the same frequency bands, for the most part, and so does the bass if its top end isn't attenuated.  The drummer had a kick drum.

The result was that it didn't matter how loud anyone was, nothing could be heard, because everyone was sitting within the 250Hz -1KHz area.

It would have been most sensible to accentuate the singer's frequencies in the PA throughout her frequency range, and add some compression to fix her loudness.  Then tailor the guitar's upper and lower range to fit round her, attenuating the mids as they crossed with her frequencies, then fit the bass at the lower end, attenuating its higher end to allow her and the guitar to work together.

But the bassist was the band leader, so he wanted his frequencies to be heard at all levels.

On a related point, I have a Mesa Nomad which was sitting in a band context and I had it set up for "Super clean", which setting boosts the bottom end, and cuts the mid and treble - gives a nice jazz sound.  Too quiet.  Even on full.

After a bit of thinking, I boosted the mid, and all of a sudden - too loud.  That's not altering the volume at all, just the midrange.

monquixote

The laptop speakers and other crap audio sources won't be able to reproduce the frequencies as low as the bassline. 

You might think this would mean that you wouldn't be able to hear the bass, but that's not how it works. The bass notes contain the fundamental and a number of higher harmonics. Even with the fundamental removed you still perceive the same notes being played. 

That's probably a bit complex if you don't know much about audio, but this site explains it fairly well. 

http://auditoryneuroscience.com/?q=topics/missing-fundamental

horse

Yeah - I think I've been under estimating the spread of frequencies potentially covered by bass instruments.

I was browsing a book called The Art of Mixing, and saw a table which breaks down what aspect of various sounds are likely to be present at different frequency bands, and bass features in nearly all the bands. Interestingly in 800-1000 it puts 'body on small speakers', so I guess I've sometimes noticed basslines defined by this frequency range through the TV.

I think where the bass is lacking in those hi-fi speakers is probably where the recorded tone of the instrument has much less mid / top, so not comparing like with like.