Hi there folks, it's been a while since I opened new thread.

In my new apartment, I'd like to build "pro" surround system for mixing and mastering, likely a quad 4.0 setup. Last week I experimented with 4.0 and was really impressed even in untreated room. Only the bass was muddy.

Bass is an issue, subs are super expensive and most of the time, the bass feels detached from the rest of the spectrum, being mono and mostly overpowered. While in most electronic genres, it's correct procedure to mix bass in centre, it's not a rule for acoustic genres (just look on orchestra charts where basses are seated), so it's preferable to avoid an LPF and single sub.
In "correct" 4.0 system, the speakers ought to be positioned in a square, but that tend to bring practical drawbacks - (not enough desk space, awkward rear speaker positioning, ...)

So does any of you have experience with surround monitor positioning and tips on treating the room for multi-speaker systems?

My existing equipment:

• Four Behringer 1C entry studio monitors
• Two Tripath Class-T TA2020 based amplifiers

Budget - possibly below $300

 

Last edited: Jul 3, 2016

4.0 is good. That way you can detect phasing issues btw C & LR. No sub is good.

You don't want to get into the LFE/sub mess, as

• 99% of the time, the LFE is abused aka upscaled from the other channels
• For digital, the LFE is +10dB then sent to the sub (BMS may apply if you have satellites)
  
• and hence consumers miscalibrate their subs for the abused LFE+bass management.

I can't comment on treatment, mine's untreated & it's fine. [How do I PM you?] I don't use the sub most of the time.

Quad 4ch has traditionally been 4 speakers in a square. Some panners (like cinema/Premiere) have 5.1 side speakers in a square.

For ITU 5.1, imagine a circle, with a centerpoint on your seating position. ITU 5.1 reccomends: place LR +-30deg and LSRS +-115deg on the edges. 115* is the surround position, but you can place them a bit further back, maybe 135*-145. 115* is actually a compromise btw 90 & 135.

If you're mixing for ITU 5.1 (30,115), use ITU panners (waves 360). Free panners exist for REAPER (which I use), but may not be ITU 5.1. Only dynamic pans will differ from layout2layout, as some pans may travel too slow/fast between speaker pairs depending on mismatch btw physic layout & plugin, which is why for mixing music I prefer static positions around the edges. (WOuld you like a guide on mixing music in surround?)

Really, your music should sound goot in all configurations. irregardless of layout.

For my setups, I don't have much choice - the rears are a bit narrower than desired due to space/layout constraints.

If you've got a 4ch from 2x2, the big annoyance is two separate volume controls. Many people have speakers + AV Receiver to do 5.1 (or whatever) so that they've got a SINGLE volume control, or try a PC AIO system like the logitech z906.

 

My intention is to build a case for the two TA2020 PCBs and link the volume control to a potentiomenter with four tracks, such as ALPS RK501.
Otherwise thanks for your very informative post.
I thought LFE gain was +20dB for AC3, but looks like I was wrong.

 

Last edited: Jul 3, 2016

+10 cuz a single LFE can make noise as loud as the 3 front ch combined in 5.1

 

From the looks of it, Altiverb 7 XL has only 8 spaces compatible with surround, that's one pure waste of money compared to regular version.

 

You can:

• Use 2x2ch reverbs for 4ch mixing. Wow. Much control.
• Use a dedicated mch reverb like Waves R360 6ch, Acon Digital Verberate Surround 8ch, VIRSYN REFLECT 12ch

Careful don't use 2 much reverb, else it may ruin the discreteness.

 

2x2ch doesn't work well for convoluted spaces, where realism is first priority. IR360 has lots of options, but Altiverb does support surround too.

 

In filmsound, a sub is a dedicated channel with no relation to the other channels, solely used for Low frequency effects (LFE). In a movie-theatre, the LR & C speakers are already full range, with sufficient low end.
Multichannel playback of stereo music however is always an up-mix, where the sub and other speaker signals are derived from the stereo signal. But mind you, this situation is prone to acoustical problems like cancellations and many many room modes. To reduce them, you'd have to build massive traps around your room, even building extra drywalls filled with mineral wool.

I'm a big fan of surround sound, but for music, I think only Ambient could benefit. There's not much low frequency in Ambient, any acoustical problems don't have to be perceived as bad, they're just part of the perception, lol..
With beat driven music, that is a total different story..

Interesting read: fixing low frequency problems with hollow tubes. Haven't tried it myself, but it makes sense:
http://web.archive.org/web/20010803052829/http://www.headphone.com/EditorialHeadroom/RoomTubes.asp
(note: the link to chapter 2 only works from the contents page)

 

(LFE +10dB for digital = sub, this is with no additional BMS)

Not having a sub, and not using the LFE is absolutely fine, especially for music. Andrew's 5" Behringer 1C entry studio monitors are fine. My L&R are smaller than that.

What you've described above, is what's supposed to happen, but actually doesn't. Ideally, you should place unique, but complementary sounds in the LFE, so that it's fine if consumers play with, or without a sub/LFE. Some movies have no LFE/don't use it.

Spoiler

I'm guessing 50-95% of studios, during 90% of the time, studios abuse LFE.

Long explanation: Studios upscale the LFE from other channels (even on discrete-ish mixes) because they think:

• the LFE existing is reason enough to use it
• Other studios do it
• If we don't use it, we'll be at an 'inferior position' when played back, like what's happened with autotune & the loudness war.

Toei does this. Disney does this. 7arcs does this. And many others I'm not bothered to check/list.

I used to abuse the LFE, and then I stopped. Easiest way to not abuse it is to not use it at all.

LFE was carried over from the 60s into the modern digital world because having too much bass in the 1ry channels would cause cross-modulation or something.

See also http://www.ambisonic.net/dvda.html#bass

You can stick stereo on L & R only, which is what's been done for some movies. This is fine. Upscaling stereo music to surround could also be fine, depending on FX chain, material, and upscaler specifics.

Not sure what you're trying to say here, but I've been mixing music is discrete surround for a few years (aka placing discrete sounds in C/Rear) sounds fine.

Here is one downmixed to quad, padded to 6ch (blank C, LFE): http://www.mediafire.com/download/o2bv9oc2ngg6phd/6LRSmidi2-40n.m4a

credits: me, Blue.Nocturne, Jayster

If you want more examples, PM me.

 

Last edited: Jul 6, 2016

My post was to ‘warn’ Andrew to just put 4 speakers in a room with 2 x the same stereo signal (and maybe even a Sub derived from that stereo signal), as it would be a bitch to treat a room acoustically in that situation. I wasn’t talking about dedicated surround mixing of music.

I made the equation with filmsound because here, the separate signals are unique, and acoustical problems would be far less.

About beat driven music versus Ambient: If you only play ambient in a 4 speaker setup, I guess that’s fine, but with any other genre, aforementioned acoustical problems will be severe without proper trapping.

interesting vid about Basetrapping:

 

Um, I never wanted to do 2x2, I only mentioned 2x2 in relation to the amplifiers, not the input signal. There it's obviously 4 unique channels.