Adding subs to a nearfield desktop system

[davybyrne]

In theory yes but did you tried it in practice?

No. Using the high-level input would mean playing the mains full-range, which doesn't make sense to me for a nearfield 2.1 setup.

REL are the ones making claims about the benefits of high-level inputs that have no basis (that I've seen) in measurable performance. The burden of proof is on them to show how it performs better that properly crossed-over subs.

 

[davybyrne]

Do the subs being discussed not have internal DSP filers with cross-over point control knobs?
If so, is there any value in concatenating a miniDSP with the sub's own DSP? That could be ADC->DSP->DAC->ADC->DSP->DAC, depending on how these things can connect....

The REL Tzero MkIII subs don't have digital inputs. My understanding is that their crossover/low-pass filter is analog.

 

[Redacted]

Most subs I was looking at when buying use ADC->DSP->DAC internally to implement LP filtering using a line level input, but if these RELs just use passive filters, then I didn't know that. My bad. Is it not a powered sub? (not that this is relevant to LP filtering)

But whatever the filtering technique is used on the RELs, (i.e. DSP or passive LCR), I'm not following why they'd need to be fed with a LP filtered output from the miniDSP as well.... Are you saying the RELs have no filtering of their own, hence a miniDSP being needed? I drive my powered subs using their line-level inputs from the pre-outs of my amp, and the subs seem to do the LP filtering just fine. As I've said elsewhere, it did take me three days to get the subs' Xover and volume settings to work nicely with my mains!

 

[davybyrne]

Most subs I was looking at when buying use ADC->DSP->DAC internally to implement LP filtering using a line level input, but if these RELs just use passive filters, then I didn't know that. My bad. Is it not a powered sub? (not that this is relevant to LP filtering)

But whatever the filtering technique is used on the RELs, (i.e. DSP or passive LCR), I'm not following why they'd need to be fed with a LP filtered output from the miniDSP as well.... Are you saying the RELs have no filtering of their own, hence a miniDSP being needed? I drive my powered subs using their line-level inputs from the pre-outs of my amp, and the subs seem to do the LP filtering just fine. As I've said elsewhere, it did take me three days to get the subs' Xover and volume settings to work nicely with my mains!

Sure, I could use the subwoofer's low-pass filter. But I also need to high pass my mains. And I need to correct timing. And I want to use PEQ for room correction. I find it easier to do all of that in one place (the miniDSP 2x4HD).

 

[levimax]

I had a pair of REL subs with the high level input. The way it works is you feed the same right and left signal as the mains speakers to the sub (It is a very high impedance load so doesn't mess with the signal to the mains even though they are wired in parallel) so there is no high pass on the mains. The REL sums to mono and has an adjustable low pass, volume, and phase adjustment. There is a recommended sequence of adjusting these "by ear" to integrate the subs. It is suboptimal compared to measurements and proper crossovers but if you don't have DSP, proper crossovers, measurement equipment, and ability to use them it can work OK.

 

[Redacted]

I had a pair of REL subs with the high level input. The way it works is you feed the same right and left signal as the mains speakers to the sub (It is a very high impedance load so doesn't mess with the signal to the mains even though they are wired in parallel) so there is no high pass on the mains. The REL sums to mono and has an adjustable low pass, volume, and phase adjustment. There is a recommended sequence of adjusting these "by ear" to integrate the subs. It is suboptimal compared to measurements and proper crossovers but if you don't have DSP, proper crossovers, measurement equipment, and ability to use them it can work OK.

Sure, but I just don't the fact that there are two power amps in series to the REL with this method (you main amp, then the the REL amp), but only one (just your main amp) to your main speakers. I'm not saying it makes an audible difference, but it rubs at my OCD!

As an aside I run always run two subs (and no reason why one couldn't do this with RELs of course). Apart from any possible "room mode" debates (and double the power!), I can say that with my system it does seem to make a difference having some "stereo effect" at low frequency....

I did a quick test a couple of years back by recording a short, low-string bass guitar riff into Audacity. I have 'proper tracks' I could have used, but I wanted to stick to having it in my control - I do have quite a lot of tracks with very low bass synths. My recording was equal L+R from a mono source, but then using Audacity to pan it left and right. On playback of the FLAC, with my main speakers literally disconnected, the panning was there on the subs, so with my specific rig, there is some stereo position effect from the two subs - and yes, I know there are tons of harmonics from a guitar, so there's not really pure low bass tone coming from the subs - it's the stuff up to 65+Hz I'm hearing.

I do appreciate that most users are using subs only for sound that is below the ~43Hz of a bass guitar, and when you get low enough, you lose the ability to discern any 'direction' for the sound - in my rig, my main speakers maybe have -3dB at 65Hz (I've IB'd them), which is probably a bit unusual. I also realize that if your music is from vinyl, low frequencies are in mono anyway. Still, it was interesting and it's easy for anyone to try out!

 

[olds1959special]

I recommend three subs. The L/R should be as big as possible and be the same model. They should be set up as stereo. Then add a third sub in the middle, (unless you can't position it so you won't kick it, or try raising it off the floor to help with this). The third sub can be a little smaller. This is how I do it. Set your LPF's the same on all three, which probably should be around 80-100Hz.

 

[dr_Evil]

Hello again, I am starting to have similar dilemma- sub for nearfield monitors: I want to try 2.1 system.
Now I have pair of 8030 Genelecs, (sound is fine and quite satisfying, with RoomEq Wizard and correction through computer only - as temporary solution).
Which subwoofer will be ok:
1. iloud sub - have internal DSP with pass-throug and room correction, but speaker isn't protected and producer is infamous for customer support
2. Genelec 7040 "analog" + miniDSP
3. Eve Audio TS107 + miniDSP
4. other?
Room: 25 square meters, generally acoustically "untreated", with only minor possible upgrades. I have basic microphone (Dayton).
I prefer details than "power and boom".
As compact as possible.
Thanks for advice.
// I found thread with similar problem, but if it is preferred to create new one, please delete my post (and accept my apology).
// I know, that there're "modern" Genelecs and Neumanns with "automagic" correction, but when cost of whole system is calculated I find it far beyond reason for my needs (with brain turned off I would prefer Gen 8361+ W371A).

 

[Marc v E]

Hello again, I am starting to have similar dilemma- sub for nearfield monitors: I want to try 2.1 system.
Now I have pair of 8030 Genelecs, (sound is fine and quite satisfying, with RoomEq Wizard and correction through computer only - as temporary solution).
Which subwoofer will be ok:
1. iloud sub - have internal DSP with pass-throug and room correction, but speaker isn't protected and producer is infamous for customer support
2. Genelec 7040 "analog" + miniDSP
3. Eve Audio TS107 + miniDSP
4. other?
Room: 25 square meters, generally acoustically "untreated", with only minor possible upgrades. I have basic microphone (Dayton).
I prefer details than "power and boom".
As compact as possible.
Thanks for advice.
// I found thread with similar problem, but if it is preferred to create new one, please delete my post (and accept my apology).
// I know, that there're "modern" Genelecs and Neumanns with "automagic" correction, but when cost of whole system is calculated I find it far beyond reason for my needs (with brain turned off I would prefer Gen 8361+ W371A).

I have the 8030 with a genelec f two, which I find a perfect match for a desktop setup or small room. Tbh I find Rew and measuring a bit of a faff, but the results are very audible: clearer voices and instruments, very nice bass extension. Can listen to them for hours.

Btw: I use the Wiim 10 parametric eq slots. Wiim optical out in sub.

 

[goofytwoshoes]

Hello again, I am starting to have similar dilemma- sub for nearfield monitors: I want to try 2.1 system.
Now I have pair of 8030 Genelecs, (sound is fine and quite satisfying, with RoomEq Wizard and correction through computer only - as temporary solution).
Which subwoofer will be ok:
1. iloud sub - have internal DSP with pass-throug and room correction, but speaker isn't protected and producer is infamous for customer support
2. Genelec 7040 "analog" + miniDSP
3. Eve Audio TS107 + miniDSP
4. other?
Room: 25 square meters, generally acoustically "untreated", with only minor possible upgrades. I have basic microphone (Dayton).
I prefer details than "power and boom".
As compact as possible.
Thanks for advice.
// I found thread with similar problem, but if it is preferred to create new one, please delete my post (and accept my apology).
// I know, that there're "modern" Genelecs and Neumanns with "automagic" correction, but when cost of whole system is calculated I find it far beyond reason for my needs (with brain turned off I would prefer Gen 8361+ W371A).

My situation is similar to yours. I have the 8040B monitors, and my room is a little bigger. I have a DAC that I really, really like (Signalyst DSC3, handles DSD only) that I thought would not make sense to keep if I got an F Two sub. But AI tells me that the F Two analog inputs stay analog all the way through the sub and out the XLRs to monitors. I will double check this with Genelec to be certain; if so, I will buy one.