Rythmik L12 Subwoofer Review

[carewser]

I agree. 2 cheaper well designed subs will sound much better than single more expensive. But often frustrating if you do not integrate with good room correction.

I finally gave my speakers some exercise today and the thing I noticed was how ****** my subs sounded when I was sitting right in front of them but off axis they sounded much better, i'm surprised that i've never noticed that before

Edit: Wow, we can't even say "******" here? That's ****** George Carlin would hate this site

 

[3dbinCanada]

I finally gave my speakers some exercise today and the thing I noticed was how ****** my subs sounded when I was sitting right in front of them but off axis they sounded much better, i'm surprised that i've never noticed that before

Edit: Wow, we can't even say "******" here? That's ****** George Carlin would hate this site

Low bass, 80 Hz and down is omni directional so there is no off axes. However sub orientation within the room will affect different room modes.

 

[carewser]

Like so many posts at this site, I have no idea what that means

 

[Alice of Old Vincennes]

Like so many posts at this site, I have no idea what that means

He means sub placement affects room nodes thar cannot be corrected by eq. Placement is difficult in home environment. 2 subs helps solve the problem.

 

[DonH56]

Room modes: https://www.audiosciencereview.com/forum/index.php?threads/room-modes.25433/

 

[xovaan]

SHD came in, got some Dirac profiles made while I wait for the dual L12’s to arrive. Took a bit of reading but I learned a LOT. Dirac is INCREDIBLE, totally black magic. Thank you SO much for the suggestion!!

Attached is the average response using AudioTools on my iPhone over fifteen seconds of Bananaphone by Raffi

 

[carewser]

Room modes: https://www.audiosciencereview.com/forum/index.php?threads/room-modes.25433/

I have 10 subs (but only 8 are hooked up) with their ports firing in all directions and the thing I noticed the last time I turned them all up is that directly in front of me the bass actually sounded kind of weak compared to off to the side where it sounded deeper, mind you my room is very small, L-shaped and with very low ceilings which i'm sure doesn't help

 

[pozz]

I have 10 subs (but only 8 are hooked up) with their ports firing in all directions and the thing I noticed the last time I turned them all up is that directly in front of me the bass actually sounded kind of weak compared to off to the side where it sounded deeper, mind you my room is very small, L-shaped and with very low ceilings which i'm sure doesn't help

I would love to see picture of a room with all those subs.

 

[Chromatischism]

I have 10 subs (but only 8 are hooked up) with their ports firing in all directions and the thing I noticed the last time I turned them all up is that directly in front of me the bass actually sounded kind of weak compared to off to the side where it sounded deeper, mind you my room is very small, L-shaped and with very low ceilings which i'm sure doesn't help

Delays and EQ!

 

[DonH56]

I have 10 subs (but only 8 are hooked up) with their ports firing in all directions and the thing I noticed the last time I turned them all up is that directly in front of me the bass actually sounded kind of weak compared to off to the side where it sounded deeper, mind you my room is very small, L-shaped and with very low ceilings which i'm sure doesn't help

What @Chromatischism said. You need to get all the delays/phasing and EQ correct at the MLP to get all those subs to play together nicely. Look into MSO (multi-sub optimizer) or something like it.

 

[xovaan]

Got the L12’s hooked up and they sound great! Used a combination of the phase control on them (I guess they like the 45 degree position?) and REW to align the subs together and again with the full range speakers albeit I still have a lot to learn with the program

I have a huge dip at 50hz but that’s likely because of my massive fabric ottoman (see attached pics). The final sub position that gives the best response after a few hours of repositioning for both is a bit weird but what can you do I guess hah. The red line is the top subwoofer and the green is the bottom

Curious: what is the best crossover frequency for the L12’s if my speakers are flat to 60hz? The internet seems to say to leave at 80hz with an LR24db roll off so that’s what I’m using right now, however I am always open to guidance

 

[Chromatischism]

I have a huge dip at 50hz but that’s likely because of my massive fabric ottoman (see attached pics)

I doubt that, but it's easy to test - move the ottoman and measure.

Curious: what is the best crossover frequency for the L12’s if my speakers are flat to 60hz? The internet seems to say to leave at 80hz with an LR24db roll off so that’s what I’m using right now, however I am always open to guidance

Anywhere from 60-80 Hz, see what sounds best.

It is an odd place for a sub, though. Can you get it up against a wall? You don't have a lot of room, but it would measure better there due to elimination of some SBIR. Maybe where the lamp is, then put the lamp on top?

 

[xovaan]

I doubt that, but it's easy to test - move the ottoman and measure.



Anywhere from 60-80 Hz, see what sounds best.

It is an odd place for a sub, though. Can you get it up against a wall? You don't have a lot of room, but it would measure better there due to elimination of some SBIR. Maybe where the lamp is, then put the lamp on top?

Here's a graph of my test (MiniDSP + SHD) against the wall just now.

The non-red are three passes using the attached settings, and the red is the three passes from the prior center-ish position. The SPL differences with the red line may be because my white noise test was 78db with the red and with the wall it was 75 for this test. Even so, it looks like the dip is reduced a full 10 decibles against the wall! That's quite the improvement!

Sub against the wall had 0* phase adjustment and the 24db/octave filter set to 120hz and the centered one was 45* phase and 80hz crossover as well. Not an exact comparison unfortunately but hopefully it's still close enough to compare?

 

[DonH56]

I like to cross over a factor of 1.5 ~ 2 times the main's -3 dB point. Speakers tend to distort heavily when presented with large deep bass signals (aren't they all? ) even if their frequency response goes that low. The crossover is not a brick wall that stops everything on either side; it is a gradual roll-off so energy still gets to the speakers/sub(s) below/above the crossover frequency. My speakers are rated to 23 Hz and I cross them at 80 Hz. You also want the sub to be able to handle room modes by placing the sub where it provides the best response, which is rarely where the mains are placed for best imaging and such. Most rooms are large enough that the fundamental modes are below 80 Hz.

 

[xovaan]

Yeah, that makes sense. My speakers are 6.5" woofers and have flat response down to 60hz, so I may have to compromise given the readings I'm finding with my left sub:

The blue line is the prior / original position, and the purple is with the sub against the hwall and couch (and ottoman) moved 16 inches forward with the ottoman slightly more centered in the room. I undoubtedly might have been positioned in a bad spot-- the move forward increased the 40-50hz range from 53db (red line, no wall + -16" back) to 68!

At this point I suppose it's a matter of figuring out 1. what that hard dip is from 65hz to 72hz and 2. if I want to correct it or just cross over at 60 and have my speakers do the heavy lifting? Or maybe it's time to start positioning the second sub to see if it fills this void? Would it be sacrilege to put the second sub on top of the first as a test point as well?

 

[CumSum]

SHD came in, got some Dirac profiles made while I wait for the dual L12’s to arrive. Took a bit of reading but I learned a LOT. Dirac is INCREDIBLE, totally black magic. Thank you SO much for the suggestion!!

Glad you love the SHD and DIRAC! It will take you a while to to get the setup perfect so don't be too impatient. There is a lot too learn and a lot to experiment with.

Firstly, use the LFE input on the Rythmik so none of its own filters are being used. There is no need to use its phase dial or crossover, that's what the MiniDSP is for. In the channel matrix, make sure both the Left and Right channels get summed into each sub.

Here are some pointers to skip you some years of pain. Always measure your speakers and your subs individually when dealing with placement and getting baselines. Find sub placements that are complimentary in frequency response and preferably close in overall output (using pink noise to measure). I see you have a null around 50Hz, well place the second sub in a spot that fills that null in. Gain match both subs when you find there forever placements, though I would keep the gain difference around 3dB and not too much higher.

For crossovers, there is no good reason to choose a frequency lower than 80Hz. If your main speakers went down to 10Hz I would still recommend crossing the subs at 80Hz. If you can get away with 90 or 100Hz then do that if it helps fill in dips (while still not being localizable). Stay away from filters greater than 24dB/Octave. 24dB BW or LR or even a Bessel is fine to use. You also do not have to match the speakers crossover point to the subs. For example I typically crossover my speakers between 50-60Hz and my subs at 80-90Hz. There is nothing magical about what I specifically choose, but there is also nothing harmful with the mismatch. You can run the mains full range if you'd like, though I would recommend cutting the lower bass to help with distortion.

Perform an acoustic time alignment in REW, this step is crucially important. And perform this step with the crossover filters on. The goal is to get the speakers and subs to play in phase with one another and combine constructively at the listening position. You can verify this by taking a measurement with the speakers and subs all sweeping at the same time. Then compare their response to an average (or sum) of all of their individual responses. They should be virtually identical if you do this step correctly. If you don't then you will create nulls and lose output.

As for DIRAC, your curve should bump the bass, have a flat midrange and roll off the treble. +6dB at 20Hz to -6dB to 20KHz is a good target to start with. Looks something like this. The default curve is extremely thin and bright sounding. A curve like this sounds full and much more neutral.

And run the subs a bit hot in volume so you can make cuts in DIRAC. Hope this info helps.

 

[xovaan]

Wow, extremely comprehensive, thank you for taking the time to lay it out clearly! I really appreciate it and it helps me visualize how to tweak everything.

So to repeat back to you to confirm that I’m reading you correctly:

1. Move subs (LFE) and speakers around the room and test individually. The goal with subs is to have each help where there are nulls (what is a good target dB?)
2. Perform a time alignment with crossovers on. A baseline is 80hz 24dB/octave for the subwoofers and 50-60hz 24dB/octave for the full range speakers.
2.1: Do I time align speakers to speakers, subs to subs, then left speaker to left sub and right speaker to right sub, then apply the ms delay time alignment then so they’re all in sync?
2.2: Do I do a peq application with REW’s target auto eq as well, and if so, do I do this before or after running the speakers and subs together? Or is all eq handled in Dirac after time alignment?
2.3: When you say a sweep with all on at the same time, what REW settings are you applying / what menus are you working with? Are you saying both subs and both speakers (four total) simultaneously? What visuals would confirm correct and incorrect phasing?

Just so we are on the same page

Anything else I’m missing?

Edit: I should say that this is an extremely fun way to spend the next few days / weeks / years

 

[Chromatischism]

Move subs (LFE) and speakers around the room and test individually. The goal with subs is to have each help where there are nulls (what is a good target dB?)

Just to be clear, the 2nd sub is placed to get the best overall response with the 1st sub already in place. You are simply playing both simultaneously and optimizing the combined result.

 

[Chromatischism]

2.1: Do I time align speakers to speakers, subs to subs, then left speaker to left sub and right speaker to right sub, then apply the ms delay time alignment then so they’re all in sync?

Subs will have the optimal alignment to each other when you find the best possible frequency response (location and delay settings).

To align to speakers, both sub delays/distances are adjusted by the same amount in unison.

However, if you are doing this with Audyssey, set both sub delays to zero before beginning. You will not optimize them yourself. The delays to align to the speakers are then done through the AVR afterward.

 

[CumSum]

Wow, extremely comprehensive, thank you for taking the time to lay it out clearly! I really appreciate it and it helps me visualize how to tweak everything.

So to repeat back to you to confirm that I’m reading you correctly:

1. Move subs (LFE) and speakers around the room and test individually. The goal with subs is to have each help where there are nulls (what is a good target dB?)
2. Perform a time alignment with crossovers on. A baseline is 80hz 24dB/octave for the subwoofers and 50-60hz 24dB/octave for the full range speakers.
2.1: Do I time align speakers to speakers, subs to subs, then left speaker to left sub and right speaker to right sub, then apply the ms delay time alignment then so they’re all in sync?
2.2: Do I do a peq application with REW’s target auto eq as well, and if so, do I do this before or after running the speakers and subs together? Or is all eq handled in Dirac after time alignment?
2.3: When you say a sweep with all on at the same time, what REW settings are you applying / what menus are you working with? Are you saying both subs and both speakers (four total) simultaneously? What visuals would confirm correct and incorrect phasing?

Just so we are on the same page

Anything else I’m missing?

1. You don't have to move your speakers, especially for bass, just grab their individual measurements. If you want to move your speakers then place them where they sound best, not where they measure best in the bass region.

For the subs, you move them where they measure best (which is where they will sound best). You can actually simulate having 2 subwoofers (or more) with just one. Just place your sub all across your room and take measurements. Then you can start averaging 2 or more measurements to see what their combined response looks like. The goal is to end up with a combined response that has no nulls (not always possible with just two subs).

If Sub X has a null at 50Hz then Sub Y should be placed to cover that null. If Sub Y has a null at 30Hz then Sub X should cover that. One sub may have a very good overall response, but suffer a few nulls. The second subs overall response might not be great, but it should at least cover those problem areas the first sub experiences.

It is a nice to have if both subs have similar output. So with both subs set to identical volumes, when you play LF pink noise on one sub the SPL measured should be close to the other (around 3dB). If they are not identical then it is a good idea to gain match both subs. For example, when Sub X is playing at 80dB, Sub Y might be playing at only 77dB given the same input signal. So give Sub Y +3dB to even it out. Keep in mind that +3dB is doubling the power needed from Sub Y's amp which is why you want both having relatively equal output. Don't boost a sub +10dB to match the output of the other.

2. When performing acoustic time alignment, the left or right speaker will act as the time reference. Example, left speaker is your time reference, well now your job is to match the right speaker and both subs to the left speaker in time. Because the measurement is done acoustically, the measured results can vary a bit regarding what volume you perform the test at, the frequency range of the sweep, etc. This is a test in my experience that needs to be run pretty loud (80+dB). Frequency sweep of 0-1000Hz works well for me. And sometimes the reference speaker needs to be run louder, REW allows you to offset the volume during the measurement. You will have to mute the subs and speakers as appropriate when running the measurements. If measuring right speaker using left reference, mute both subs, and run the test using the right channel. If measuring one sub, mute the right speaker and the other sub, and again use only the right channel (since the left is the reference).

Start by preforming an acoustic measurement of your left and right speakers. Both speakers should be the same distance from your listening position. There timing difference should be very close to 0. Then compare the left speaker to sub 1 and then left to sub 2. The furthest measuring source will have their delay set to 0. The closest measuring source will have the most time delay.

You only use DIRAC to perform the room correction. Do not use REW's auto EQ. No PEQ's should be used before performing DIRAC.

3. I failed to mention earlier that you want the subs to receive summed input from both the L/R channels using the channel matrix in the MiniDSP. So Sub 1 and Sub 2 should receive both L/R signals.

A combined measurement in REW, would be running a stereo measurement, that way the L/R speakers plus both subs are sweeping together. The combined response should be very close to the individually combined response. If that happens then that means you are in phase. If the combined responses differ greatly then you are having issues with phase. Note you are only looking at the response up to about 200Hz. Differences above that frequency will happen for other reasons you are not concerned with.