Question about sound processing. TV -> 2.1

steinooo · 30 Sep 2014 at 11:58

Hi all,

This may be a stupid question but I've been thinking about getting a 2.0 or 2.1 speaker system for the TV in the lounge.

I don't have a dedicated AV Receiver which I understand "sorts out" the channels, i.e. the 2 stereo channels and the 1 "bass" channel.

My question is, what happens if you don't have an AV receiver and buy a 2.1 system? How does the sub know which frequencies or channel to "play"? Does it muddy the sound somewhat?

To be specific I have a TV which can output through a 3.5mm headphone socket, and was thinking about getting the "Microlab FC330" as from what I understand are active, so don't require an amp/AV receiver, although I was wondering if because it's processing more than 2 channels, if the sound will be "muddied"?

Marine-RX179 · 30 Sep 2014 at 12:22

For a active 2.1 speaker, the bass share the same channel as one of the two channels...but I can't remember if it is right or left channel by default.

steinooo · 30 Sep 2014 at 13:47

Cheers for that, so I suppose if it shares a channel properly, it will receive the correct levels of bass.

One more question, if the speakers I am looking at have only 2 x phono input, will I get good quality sound by connecting them to the headphones out socket using a 3.5mm jack to 2 x phono cable? As my TV doesn't have 2 x phono out

Marsman · 30 Sep 2014 at 14:02

Bass (.1) doesn't have a separate channel like 5.1/7.1. When using 2.1 speakers, the bass frequencies are part of both channels just like stereo (2.0). If bass frequencies were only sent to one of the channels, then stereo speakers or headphones would not work properly. You'd only get bass from left or right.

There is a crossover inside the speakers, which sorts out which frequencies are sent to each type of driver; tweeter, mid range and subwoofer. Same applies to stereo as it does to 2.1, when there are more than one driver/woofer within each speaker housing.

One more question, if the speakers I am looking at have only 2 x phono input, will I get good quality sound by connecting them to the headphones out socket using a 3.5mm jack to 2 x phono cable? As my TV doesn't have 2 x phono out

To be honest, it won't be as good as it could be. The reason is that the sound is passing through the TVs internal amplifier first, then is amplified again by the speakers. Amplifiers in TVs are never that good because they only have to drive cheap piddly little speakers in the TV itself.

If you have only 3.5mm output on the TV, then there is nothing you can do but use it. RCA audio output or optical would be much better if the TV has one or the other.

steinooo · 30 Sep 2014 at 15:09

Marsman said:
Bass (.1) doesn't have a separate channel like 5.1/7.1. When using 2.1 speakers, the bass frequencies are part of both channels just like stereo (2.0). If bass frequencies were only sent to one of the channels, then stereo speakers or headphones would not work properly. You'd only get bass from left or right.

There is a crossover inside the speakers, which sorts out which frequencies are sent to each type of driver; tweeter, mid range and subwoofer. Same applies to stereo as it does to 2.1, when there are more than one driver/woofer within each speaker housing.

thanks that is a really helpful explanation.

To be honest, it won't be as good as it could be. The reason is that the sound is passing through the TVs internal amplifier first, then is amplified again by the speakers. Amplifiers in TVs are never that good because they only have to drive cheap piddly little speakers in the TV itself.

If you have only 3.5mm output on the TV, then there is nothing you can do but use it. RCA audio output or optical would be much better if the TV has one or the other.

Ah I see - the reason I ask is that I would like the sound to be controllable via a remote. I'm not fussed if it's a seperate remote from my TV but the Microlabs FC330 do not seem to have a remote at all.

I have optical out but the speakers I was looking at (Microlabs FC330) only have phono in, I did a quick search and noticed they have a newer model, the FC360, I can't find as many glowing reviews about the sound quality, and the difference being that they have a 3.5mm input, but I suppose that will also pass through my TV's rubbishy amp. That's a shame, as these were perfect regarding my small budget and size restraints.

EDIT: I have just seen that optical to phono converter boxes exist for just £5 on auction, would this suffice to pass the audio to the speaker's own powered amp do you think? Maybe that's a good option for me?

Marine-RX179 · 30 Sep 2014 at 15:43

steinooo said:
I have just seen that optical to phono converter boxes exist for just £5 on auction, would this suffice to pass the audio to the speaker's own powered amp do you think? Maybe that's a good option for me?

I'm no expert on this, but this may give you a better idea:
http://www.whathifi.com/forum/home-cinema/converting-optical-digitial-audio-to-stereo-phono

steinooo · 30 Sep 2014 at 15:57

Cheers for your help, looks like my TV -> DAC -> Active speakers idea should work

Albeit the DAC could be a weak part of the solution and could reduce quality somewhat . I suppose in that case it's a toss up between the TV's amp using the 3.5mm headphone jack and the cheap DAC potentially hurting the sound.

rids57 · 30 Sep 2014 at 16:21

If you send the signal out to a DAC then you lose control from the TV's remote, so you need to make sure that the speakers have one.

why not get a soundbar and feed it with the optical output - they all have remote controls too

steinooo · 30 Sep 2014 at 16:33

rids57 said:
If you send the signal out to a DAC then you lose control from the TV's remote, so you need to make sure that the speakers have one.

why not get a soundbar and feed it with the optical output - they all have remote controls too

Good point cheers Rids, I looked at soundbars but these cheap speakers seem to be reviewed quite well against cheap soundbars. (i've not got much budget as I've made too many mistakes with my home audio)

Marine-RX179 · 30 Sep 2014 at 17:36

steinooo said:
Good point cheers Rids, I looked at soundbars but these cheap speakers seem to be reviewed quite well against cheap soundbars. (i've not got much budget as I've made too many mistakes with my home audio)

Yea personally I not a fan of soundbard, as it's bass is non-existence without a sub.

I don't know what budget you got or how much you can spend, but the issue is that most sub-£100 speakers won't have optical input.

It would most probably be out of your budget, but may be you could consider something like the Microlab Solo 8C/9C, which have optical input and remote, and it will have big enough bass without the need of a sub.

Marsman · 30 Sep 2014 at 19:06

As already pointed out, cheaper soundbars will be quite tinny without a subwoofer. More expensive ones will fair better, but I feel such a soundbar will cost much more than you are willing to spend. Cheaper soundbars with a subwoofer are an option, but probably aren't that good. Maybe for general TV they are OK though.

Marine's suggestion of Microlab Solo, is a good one. Even the 1C or 6C will be a good choice as they still have fairly large woofers (more so in the case of the 6C). Both have remote control, but only RCA input. A cheap DAC will need to be added as well, but should keep the cost under £100.

If you're looking to spend around £50 or no more, then the cheaper 2.1 sets and using the headphone on your TV will be the best bet.

steinooo · 30 Sep 2014 at 19:19

Marsman said:
Marine's suggestion of Microlab Solo, is a good one. Even the 1C or 6C will be a good choice as they still have fairly large woofers (more so in the case of the 6C). Both have remote control, but only RCA input. A cheap DAC will need to be added as well, but should keep the cost under £100.

Thanks guys for this valuable input, do you think a cheapo £5 DAC would detriment the quality of whatever I go for? (perhaps even as much as using the headphone socket?) I realise this option would also lose me the remote control function too.

If you're looking to spend around £50 or no more, then the cheaper 2.1 sets and using the headphone on your TV will be the best bet.

This Microlabs FC330 is sub £50 and has amazing reviews lots of people saying it far outperforms it's price tag. The problems being (for me) the analog only in, and no remote....

Marsman · 30 Sep 2014 at 19:28

Well no doubt a £5 DAC would not as good in comparison to say a FiiO D3 for £30; however, the DAC process isn't really the problem when using the headphone socket on the TV. The problem is that you are getting double amplification, and poor first amplification from the TVs internal amp. With a DAC whatever it costs, the signal will be cleaner and therefore, should be better.