General SUBwoofer Advice Thread

Discussion in 'Speakers' started by shotgunshane, Dec 31, 2019.

  1. ogodei

    ogodei Headphone Heaven Gatekeeper

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    @zonto, I used the SubDudes under my Rythmik FV15s back in the day, I now have SVS PB-16s and SB-4000s, all on SVS SoundPath Isolation feet.

    The foam on the subdudes is soft, open cell stuff. Your sub & the wood platform kinda 'float' on the foam meaning you can sway it around a good deal. Think of a worn out car suspension, kinda floaty, lazily springy. It works but I cant say its better than the SVS isolation feet, and I prefer the look of the feet.
     
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  2. jnak00

    jnak00 Friend

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    Would you recommend the isolation feet if the sub is on a basement (concrete) floor?
     
  3. Metro

    Metro Friend

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    Probably unnecessary for a concrete floor because it won't transmit much vibration from a sub. The problem is primarily with wood flooring on framing that can easily conduct vibration throughout a room and house.

    As a side note, I have the REL T/7i, and REL does not recommend isolation feet for their products. Most of their models have a downward firing driver or radiator that is tuned for an exact distance from the floor, and isolation feet would raise the height. However, if you have vibration issues in your room, you have no choice but to use an isolation platform or feet.
    https://rel.net/blog/2021-10-26/q-a...esnt-recommend-subwoofer-isolation-platforms/
     
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  4. yotacowboy

    yotacowboy McRibs Kind of Guy

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    Actually, this is an opportunity to mass-couple the sub to the floor/room. This is where I would start with spiking the subs instead of isolation feet, and consider adding even more weight on top of the sub, too. Some of the best bass extension I've ever had in my room was when I lived in a below-grade, poured concrete construction apartment; I put a Hsu sub in the corner, spiked it, and playing things like Saint-Saens organ stuff with true 16hz pipe organ fundamentals stuff was just nutty.
     
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  5. rhythmdevils

    rhythmdevils Best SBAF member of all time

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    I bought a Rhymic L-12 a while ago based on recommendations here. I didn't realize how big it is, its serious overkill for my room right now. But moar bass = gooood right? Just kidding, but I probably have a sub that will be all I ever need now.

    I'm in over my head with all the settings, and I don't have DSP or any kind of mic or gadgets to dial in the settings so it will all be by ear. I'm pairing them with Mackie HR624 mk1 monitors. I'm planning on setting the low cut filter on the Mackies to 80hz.

    I'm then going to adjust volume until it sounds neutral I guess. the thing I don't know much about is phase and how to adjust that by ear.

    Any advise for phase, or just generally setting up a sub by ear would be appreciated!

    I'm hoping my speakers will sound better without having to produce such deep bass, and then also get bass extension all the way down, I'm don't want them to sound bassy.

    I've got some pretty good room treatments including in the corner where the sub is so I;m not expecting a lot of issues with that.
     
  6. Garns

    Garns Friend

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    This is how I set up my subs by ear. Not saying this approach is necessarily the best, but it worked for me. I started from a flac file I created:

    scales.flac

    Descending D major scale from D3 = 147Hz to D1 = 37Hz. It's easy to diagnose problems because you can find the Hz of the interposing notes, e.g. here.

    Put the track on repeat, fiddle with the cutoff and gain until it sounds moderately even (except for the inevitable room modes which you can calculate from your room dimensions). Before using this, just setting up by ear alone, I got the cutoff way too low. (You seem to have great ears so probably have done better than me.)

    Now you can make a pass at phase. Each note has an attack segment which sounds weird unless the phase is set correctly. The higher notes will be coming completely through the mains so you should hear what the attack should sound like. I start at 0 delay and step up one by one. There should be a point where it snaps into focus.

    Of course you then have to listen to loads of music to fine tune the settings but this got me in the right ball park pretty quickly. For phase, anything with a kick drum with a prominent beater and not too much else going on is pretty good for making sure you have it right. I've been using this track:

    https://roziplain.bandcamp.com/track/swing-shut
     
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  7. randytsuch

    randytsuch Facebook Friend

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    If you could get your hands on a umik for a bit, then you can run REV software and use that to setup your sub.

    I used REW and a mic a long time ago when I was running a sub with some desktop speakers, was fairly easy from what I remember. I also had a minidsp box, but if you can filter your monitors at 80 Hz, you can make all the adjustments on the Rythmik.


    Randy
     
  8. RenEH

    RenEH Rando

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    I have a HSU ULS-15 sub that I resurrected with an Behringer iNuke 3000 pro amp and have been happily using it in home theater applications for about 7 years.

    Now I want to use it in a two channel system with an Akitika gt-102 z4 amp and some Magnepan LRS, but amp has no sub pass through. What’s the best/cheap way to integrate that speakers and sub together?

    I saw on YouTube something about some kind of sub pass through from parts express, but I’m wary since using high level inputs on a parts express plate amp on another resurrected HSU subwoofer introduced a lot of noise.
     
  9. ergopower

    ergopower Friend

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    MiniDSP is used widely for exactly this purpose
     
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  10. RenEH

    RenEH Rando

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    Thank you! Any advantage for a mini DSP over say a modi 3 running the same source connected to a Schiit sys and then the pro amp? Already have a spare modi 3.
     
  11. ergopower

    ergopower Friend

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    No DAC is going to have the circuitry to split an incoming line-level signal into 2 signals above and below a crossover frequency. You really want this, because then the Akitika and the Maggies are only going to have to deal with e.g. > 80Hz and you let the sub do its thing < 80Hz. MiniDSP is between the Akitika and whatever your upstream source is, likely a DAC

    Edit: there are a good few pro DACs that have this functionality, but they're probably going to well exceed the cost of a Modi and a MiniDSP
     
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  12. RenEH

    RenEH Rando

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    Thank you, does the mini DSP just split off the output of the DAC, or is there an ADC in the mini DSP to perform the active cross over? I should have mention that the iNuke already has a DSP built in.
     
  13. ergopower

    ergopower Friend

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    If I read Behringer's site correctly, it has DSP before the amp circuit, but you can only choose one of 3 modes: full-range, > 100Hz or < 100Hz. If you're using it to drive a subwoofer, there is not a way to extract the > 100Hz line level signal to drive the Akitika. This is what a MiniDSP does.
     
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  14. RenEH

    RenEH Rando

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    Oh, no this model has a full DSP and PEQ. Only issue is that it doesn’t really do below 20hz well. My worry is that with the mini DSP is the DAC’s signal will need to go through an ADC of the mini DSP than the DAC of the mini DSP.

    If that’s the case, I guess I could buy or make a high pass for the speakers and do all the DSP on the iNuke? Any negatives to the passive high pass before hitting the LRS?

    Model of pro amp here: https://www.behringer.com/product.html?modelCode=P0AHO

    Thanks again for the help!
     
  15. ergopower

    ergopower Friend

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    You need a line-level output to drive the Akitika, no? There is no output like this from the Behringer. What is upstream from the Behringer and Akitika right now?
     
  16. RenEH

    RenEH Rando

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    My upstream gear is a pi2aes-> ares 2 dac->Schiit sys->Akitika

    My plan is to use the fact that the pi2aes outputs to all of its outputs at once to run a modi 3 in parallel to the inuke3000dsp.
     
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  17. ergopower

    ergopower Friend

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    That will work
     
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  18. RenEH

    RenEH Rando

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    Do you know if a discrete high pass filter on the magnepans will screw up the sound?
     
  19. ergopower

    ergopower Friend

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    If done correctly, no. You would want to do that at line-level before the Akitika for 2 reasons - Akitika doesn't have to shoulder the load, so will have more headroom at same apparent speaker loudness; and a line-level filter is much cheaper because it doesn't have to have the current and voltage rating of a speaker-level filter. Your filter could be passive or active, you can find schematics or completed products pretty easily for both. I've never used active, so I can't say if they're better or worse. If you DIY a passive, you can make sure to use good quality caps and air-core inductor. You don't have to go nuts on the caps since it's low frequency, but at least use decent film caps.
    You're going to have delay differences between speakers and sub because of the different signal paths for each, but the iNuke can adjust delay if necessary.
     
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  20. Riotvan

    Riotvan Got lost for three weeks at Delft City Hall

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