Subwoofer setup with using digital out on MacBook Pro

straydog

Novice Member
Hello guys,

I am new here, and trying to set up a small system for CD quality (or perhaps more) streaming through Spotify. (I will of course consider their high quality HiFi service which hasn't arrived yet, but I am not on Tidal - yet)

Initially I was using Apple's AirPlay service through my Marantz M-CR603 which is a bit outdated now, and people consider it as a "bedroom amp" rather than a proper system, but I would first try it without an expensive amp upgrade).
Just discovered that my late 2013 MacBook Pro supports optical digital out and it can easily be connected to the amp using Toslink-3.5 mm mini-Toslink connector. The sound is great and it's not using the network unnecessarily, so I'm sort of happy with it. Also experience a few cut-outs with the Airplay, I believe it's more like the small Marantz is buffering the data (tend to do this with lossless FLAC) or just due to it's low speed ethernet connector/processor, could be that their AirPlay app is far from being perfect.

Just ordered a sub with low and high pass filter, but the sub has no digital in. So if I need to connect the laptop to the sub and then the sub to the amp with HPF enabled, then I would probably need a DAC.

My question is: do you think I should try the MacBook's analogue headphone out first or should I get a simple DAC straight?

I am new to the DACs, but realised that DACs with an optical digital input are much less expensive, but of course not sure about their performance. Could someone recommend a decent/mid range DAC for my need? Honestly I do not need anything better than a good CD quality sound

Another question is that some people say that HPF is not recommended for the main speakers as a subwoofer normally fills in the missing lows and complement the main speakers. Once you apply an additional circuit, a HPF would degrade sound quality on the main speakers... I do not know, of course I need to experiment with it. I would assume that you may not want to use HPF on high end amps and speakers. Not sure. At some point I will consider to upgrade the amp, but even some very expensive systems have no HPS or for instance NAD receivers using a 150Hz HPF which does not seem to be a good choice to me
All answers are appreciated. Thanks in advance!
 

MaryWhitehouse

Well-known Member
Hi and welcome

In my experience airplay is pretty reliable and usually only stutters when sent from a phone and that phone uses processing for something else, and then rarely. If you’re airplay direct to amp then Ethernet is probably irrelevant.
You don’t need a DAC though it may improve sound. You need to connect the sub to your amp as well as speakers.
What do you mean by HPF?
 

straydog

Novice Member
Hi and welcome

In my experience airplay is pretty reliable and usually only stutters when sent from a phone and that phone uses processing for something else, and then rarely. If you’re airplay direct to amp then Ethernet is probably irrelevant.
You don’t need a DAC though it may improve sound. You need to connect the sub to your amp as well as speakers.
What do you mean by HPF?
Thanks for your reply.
The sub has a low pass filter (LPF) which you can set anywhere between 30-130Hz I think, and there is a high pass filter (HPF) switch on the sub which acts as a crossover and this "output" can feed the signal to the amp. In this setup you need to connect the source directly to the sub.

Although the easiest setup is where a sub connected to the amp (through mono RCA connector labelled as "SUB") with a LPF adjusted on the sub and the main speakers of course connected to the normal way, the source would be the laptop connected to the amp via digital out (optical), not to the sub.
On the Marantz I can set response curves for the speakers but only at 60 or 100 Hz. It would act as a high pass filter. I would probably try those first, before getting a DAC - as it might not be necessary after all
 

MaryWhitehouse

Well-known Member
Hello

You don’t need a DAC. You never connect a normal line level source to a sub. The sub never feeds anything to the amp. On the amp it sounds like you can set the highest frequency that gets sent to the sub. This would normally be around 80hz but play and see what sounds best.
 

Rodders53

Distinguished Member
What sub have you bought (link to it please for the manuals/specs)?

@MaryWhitehouse
Apparently some subs do have signal in and out on RCAs intended for input from a device (e.g CD player) and outputs to powered (amplified) speakers.
These outs might be low frequency filtered aka high pass filtered? Edifier T5 is one such device T5

EDIT
I'd suggest that buffering issues are most likely down to dodgy wifi and that may need improving first? Audio streaming - even in high res - is not especially demanding.
 

straydog

Novice Member
What sub have you bought (link to it please for the manuals/specs)?

@MaryWhitehouse
Apparently some subs do have signal in and out on RCAs intended for input from a device (e.g CD player) and outputs to powered (amplified) speakers.
These outs might be low frequency filtered aka high pass filtered? Edifier T5 is one such device T5

EDIT
I'd suggest that buffering issues are most likely down to dodgy wifi and that may need improving first? Audio streaming - even in high res - is not especially demanding.
Yes this sub has an output signal through RCA/TRS and you can apply a HPF on it, this is why I purchased it...basically you set the LPF and this sets the HPF as well.
It is designed to be used with the Eris series of active studio monitors, they actually sound perfect so that's why I ordered their sub as well. I've got the Eris 4.5 for this pc (separate from my hifi, I bought this for a keyboard)

No sure about the dodgy wifi, I have a 1Gbit net (it is only 950Mbps on an ethernet connected linux pc). Wifi can only do 3-400Mbs download on the internet, but it is with high specs, latest cable modem - that's from the service provider anyway. The wifi is actually pretty good, can do 2.4 and 5GHz. Not sure about some possible occasional interference
The bottleneck could be the old macbook pro, not sure. I used to have a problem with it on an older wifi network (I bought it around 2013, but did not used it much - for playing audio), so I also though it must be the wifi. It does not do the "cut offs" very often now. Maybe only when I am doing something else on the macbook... but it did it once or twice maybe
 
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straydog

Novice Member
another question. I bought the Presonus Eris 4.5 (active studio speakers) just for a midi keyboard and it was initially connected to Focusrite Scarlett Solo (on an iMac) via TRS cables. Then I just happened to listened to spotify occasionally on the iMac. There was this other Linux Pc next to it and its wireless mouse produced strong interefrence to the system.
by chance I connected the Eris 4.5 to this PC via RCA (mini intel PC, sound goes through HDMI to the monitor, and the monitor has a mini jack output, I connected this to the RCA input on the Eris 4.5. There was no interference at all !!!! Perfect sound.
Now that I tried it on the same PC with the sub, again using RCA to the sub, the RCA output from the sub to the Eris 4.5, it produced poor sound with lots of interference, mainly from the mouse and possibly from the display as well.
Interestingly using this old MacBook Pro laptop with its headphone mini jack output (mini jack-RCA to the sub, RCA out from the sub to the studio speakers), the sound is amazing! Any ideas why the sound is soo bad when the sub is connected to the PC? Could this be the cable? of course it is the cheapest crap RCA cable. An expensive TRS cable produced the same interference as well, but it was at least 3 m long!

Anyway I supposed to use the sub with my amp, not the studio speakers.
It sounds brutal btw, love it!
 
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MaryWhitehouse

Well-known Member
Ah ok that’s a rather more unusual bit of kit. I take it you’re meant to use the Marantz as a preamp and then feed on to the powered monitors? Still shouldn’t have anything coming back to the Marantz.
Think you’ve answered your own question about stuttering. If the MacBook is being used for other things at the same time it will happen.
 

straydog

Novice Member
Ah ok that’s a rather more unusual bit of kit. I take it you’re meant to use the Marantz as a preamp and then feed on to the powered monitors? Still shouldn’t have anything coming back to the Marantz.
Think you’ve answered your own question about stuttering. If the MacBook is being used for other things at the same time it will happen.
No no sorry I did not want to confuse you with the studio speakers seput, that's a separate system, the sub just been delivered and I tried it out on the PC/mac.

At the moment the Marantz is connected to a pair of MA BX2 (2011) - see my first thread. and this produces very disappointing sound. I started listening to music again since I've got the Presonus monitors on the PC. Monitor Audio set me back for years!!!!

So I may want to connect the source (laptop) to the sub in (RCA), set the low pass filter (80Hz?), switch the high pass filter (HPS) on, and connect the sub out (RCA) to the amp (Marantz).
The laptop's analogue headphone output however may not produce a good signal alone, that's why I asked about a DAC.

It is however easier to connect the laptop to the amp with an optical cable (mini Toslink 3.5 to the MacBook Pro headphone jack-digital audio in (Toslink) on the amp.
Connect the sub to the amp, set the LPF to either 60 or 100Hz to match the HPF in the Marantz (speaker response curves).
Or simply leave the response curves flat and experience with the LPF on the sub, just to fill the space with the lows the main speakers cannot produce.
The main speakers are on their way - to replace the sh*tty BX2s
 

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