Double subwoofer advantage when combining different types.

[Droogne]

Hey

I'm planning on using different types of subs together: the horn loaded sub I already have (from 35-80hz) and a  different sub for below. When people say there is a mayor advantage in using 2 subs, does this also counts when doing it like I do? Or would I need 2 of each to get the true advantage? 

Or could I place 2 of them in the front, and 2 to the sides? Or would you need better pics to know that? I can also use measuring gear to test if this is possible. 

[SME]

The biggest advantages for multiple subs arise when the different subs have overlapping frequency response.  However, the full benefits can only be realized when the different subs have similar output capability.  The advantages in this case are: increased output over one sub alone, and smoother in-room response.  When the two subs are mismatched in output capability, then you can still achieve smoother in-room response but only by substantially wasting the capability of the stronger subs.  That's because the smoother response requires the different subs to be run at approximately the same level, and the weaker sub will reach its limits at much lower level than the strong sub.

There are some minor benefits to your usage of different subs for different ranges.  For one, the different subs can be optimized to play their respective ranges.  For example, the horn is very good above 40 Hz,  and you can get away with building deep bass subs using drivers that don't do mid-bass well.  You also will gain headroom and see less distortion when reproducing wide-band sub-bass signals.  However, as with multiple subs handling an overlapping range of frequencies, the benefits are greatest when the output capability of the subs handling each range is approximately matched.  Though how they should be matched depends a bit on the content you play and on room gain effects.  For example  a lot of music doesn't extend much below 40 Hz, so the horn may be able to handle that very well on its own and reach quite high levels.  For home theater, however, a lot more bass extends into the 30s, 20s, or lower.  It'll likely take a lot of output to keep up with the horn.  Of course, that may not be a big deal if you don't ever push the levels that high.

On another note, integrating subs of different types can be very tricky.  You will want to do a lot of measurements and experiment a lot with different distance and possibly EQ settings to get the smoothest integrated response.

[Droogne]

22 hours ago, SME said:

The biggest advantages for multiple subs arise when the different subs have overlapping frequency response.  However, the full benefits can only be realized when the different subs have similar output capability.  The advantages in this case are: increased output over one sub alone, and smoother in-room response.  When the two subs are mismatched in output capability, then you can still achieve smoother in-room response but only by substantially wasting the capability of the stronger subs.  That's because the smoother response requires the different subs to be run at approximately the same level, and the weaker sub will reach its limits at much lower level than the strong sub.

Ok, I'll probably have to buy another horn sub, or I just might sell this one in the future (poor resale value though, not perfectly build :s) and build a wall of sealed (or ported) subs. Would I have smoother rooms response with the horn aimed at the corner (with a top plate) or does this only increase the dB? 

22 hours ago, SME said:

There are some minor benefits to your usage of different subs for different ranges.  For one, the different subs can be optimized to play their respective ranges.  For example, the horn is very good above 40 Hz,  and you can get away with building deep bass subs using drivers that don't do mid-bass well.  You also will gain headroom and see less distortion when reproducing wide-band sub-bass signals.  However, as with multiple subs handling an overlapping range of frequencies, the benefits are greatest when the output capability of the subs handling each range is approximately matched.  Though how they should be matched depends a bit on the content you play and on room gain effects.  For example  a lot of music doesn't extend much below 40 Hz, so the horn may be able to handle that very well on its own and reach quite high levels. 

The horn sub does a terrific job at keeping up with the rests of my setup in music situations. Tried to boost the low end earlier this morning, but i ended up with something weird (I think it was missing the midbass punch I felt earlier). It did improve majorly in the lower end, so I got a satisfying LFE punch for movies (till I get the dedicated low end subs). Will recalibrate the settings and see if I can fix the midbass (40-80) hz punch I had earlier. 

22 hours ago, SME said:

For home theater, however, a lot more bass extends into the 30s, 20s, or lower.  It'll likely take a lot of output to keep up with the horn.  Of course, that may not be a big deal if you don't ever push the levels that high.

Now that I have my UMIK I can try to see what exact SPL I have at max. listening volumes (which is not pretty high, as I have neighbours, lots of them). 

22 hours ago, SME said:

On another note, integrating subs of different types can be very tricky.  You will want to do a lot of measurements and experiment a lot with different distance and possibly EQ settings to get the smoothest integrated response.

I was planning on trying out mixing different subs, but not to hope for it giving a satisfying result. But who knows. Counting on  sealed or ported below 35hz, and the horn sub above that. Both seperated with a steep crossover so they dont mix. That should work right? 

[SME]

8 hours ago, Droogne said:

Ok, I'll probably have to buy another horn sub, or I just might sell this one in the future (poor resale value though, not perfectly build :s) and build a wall of sealed (or ported) subs. Would I have smoother rooms response with the horn aimed at the corner (with a top plate) or does this only increase the dB? 

What does your room layout look like?  The direction that the horn is aimed will have minor effects.  The major effect will be based on where it's located.  Corners that are far from other boundaries are usually best.  It looks like there is an opening on the left side of your room.  It doesn't really count as a corner for sub purposes unless there is quite a bit of wall length extending on both sides.  Is the right side closed off?  If so, you might want to try swapping out the horn for electronics stack to put it closer to the right side.

Usually corner placements give you more dB and are likely to reduce interference effects from nearby boundaries.  They will substantially activate room modes though.  A common approach is to put one sub each in adjacent corners, which helps cancel out modes between the opposing walls.  Of course, the most sure way to know what works best is to experiment and measure.  Measurement at multiple locations is helpful.

8 hours ago, Droogne said:

The horn sub does a terrific job at keeping up with the rests of my setup in music situations. Tried to boost the low end earlier this morning, but i ended up with something weird (I think it was missing the midbass punch I felt earlier). It did improve majorly in the lower end, so I got a satisfying LFE punch for movies (till I get the dedicated low end subs). Will recalibrate the settings and see if I can fix the midbass (40-80) hz punch I had earlier. 

Too much deep bass will eat the mid-bass punch.  It is due to a perceptual effect called masking.  It is why the best sounding systems are neutral, and why audio engineers strive to make their systems neutral so that when they EQ their work to perfection it has the best chance of sounding great on everyone else's ideally neutral systems.  You want to adjust things to get just the right balance.  The ideal response may be within +/- 1 dB (in a coarse sense) or even less.

8 hours ago, Droogne said:

Now that I have my UMIK I can try to see what exact SPL I have at max. listening volumes (which is not pretty high, as I have neighbours, lots of them).

You have neighbors and you are running a horn?  Do you live in a detached house?  How far away they?  Do you have an SPL meter?  IIRC, the UMIK does not ship with absolute SPL calibration info.  It has a cal file for relative frequency response, but won't tell you precisely how loud things are.

8 hours ago, Droogne said:

I was planning on trying out mixing different subs, but not to hope for it giving a satisfying result. But who knows. Counting on  sealed or ported below 35hz, and the horn sub above that. Both seperated with a steep crossover so they dont mix. That should work right? 

Maybe, but it won't necessarily be easier than milder crossover slopes.  Even steep crossovers have a fair amount of overlap.  At least you have the mic so you see what the response looks like while you try to optimize the integration.

One more question:  Do you care about sound quality at multiple seats?  Or are you focused on just one?

[Droogne]

3 hours ago, SME said:

ectio

 

3 hours ago, SME said:

What does your room layout look like?  The direction that the horn is aimed will have minor effects.  The major effect will be based on where it's located.  Corners that are far from other boundaries are usually best.  It looks like there is an opening on the left side of your room.  It doesn't really count as a corner for sub purposes unless there is quite a bit of wall length extending on both sides.  Is the right side closed off?  If so, you might want to try swapping out the horn for electronics stack to put it closer to the right side.

It's open to the right side (to both the kitchen and the hall, so around 20 sq. meter (215 sq feet) in the main room, and another 150 sq feet in the adjacent part). The wall from the right corner to the opening is longer, 7 feet at least.

3 hours ago, SME said:

Usually corner placements give you more dB and are likely to reduce interference effects from nearby boundaries.  They will substantially activate room modes though.  A common approach is to put one sub each in adjacent corners, which helps cancel out modes between the opposing walls.  Of course, the most sure way to know what works best is to experiment and measure.  Measurement at multiple locations is helpful.

With measurement at different locations, you mean the sub in different placements? Or could the measurements work like the "subwoofer crawl"? With the sub in the MSP and measure possible placements? 

3 hours ago, SME said:

Too much deep bass will eat the mid-bass punch.  It is due to a perceptual effect called masking.  It is why the best sounding systems are neutral, and why audio engineers strive to make their systems neutral so that when they EQ their work to perfection it has the best chance of sounding great on everyone else's ideally neutral systems.  You want to adjust things to get just the right balance.  The ideal response may be within +/- 1 dB (in a coarse sense) or even less.

Almost impossible to EQ the response below 37hz (due to the horn), but this is what I got: as you can see I got a pretty big 15db dip between 44 and 50hz, but I'm guessing thats room cancelation? Just test it, and although there is a 6db jump @37 it does sound OK (tested it with Hacksaw ridge and it did give some pretty neat low bass punches! Did move the crossover a bit higher to at least 30hz, as to not push the horn too much)  

3 hours ago, SME said:

You have neighbors and you are running a horn?  Do you live in a detached house?  How far away they?  Do you have an SPL meter?  IIRC, the UMIK does not ship with absolute SPL calibration info.  It has a cal file for relative frequency response, but won't tell you precisely how loud things are.

Not a detached house, but dont mind that  act like I do haha. I'll deal with the neighbours (pitchforks and all). I'll try to get my hands on a SPL mic to calibrate the UMIK.

3 hours ago, SME said:

Maybe, but it won't necessarily be easier than milder crossover slopes.  Even steep crossovers have a fair amount of overlap.  At least you have the mic so you see what the response looks like while you try to optimize the integration.

One more question:  Do you care about sound quality at multiple seats?  Or are you focused on just one?

One or 2 seats is OK. Other people visiting dont know  or care about quality I've noticed  It's mainly me and my brother, and I'm the only one who cares about the quality  

[SME]

12 hours ago, Droogne said:

It's open to the right side (to both the kitchen and the hall, so around 20 sq. meter (215 sq feet) in the main room, and another 150 sq feet in the adjacent part). The wall from the right corner to the opening is longer, 7 feet at least.

With measurement at different locations, you mean the sub in different placements? Or could the measurements work like the "subwoofer crawl"? With the sub in the MSP and measure possible placements?

The sub crawl approach works great if you're only really concerned about one seat location.  Just put the sub there, preferably propped up so the horn is at ear level and then test each of the different candidate locations.

12 hours ago, Droogne said:

Almost impossible to EQ the response below 37hz (due to the horn), but this is what I got: as you can see I got a pretty big 15db dip between 44 and 50hz, but I'm guessing thats room cancelation? Just test it, and although there is a 6db jump @37 it does sound OK (tested it with Hacksaw ridge and it did give some pretty neat low bass punches! Did move the crossover a bit higher to at least 30hz, as to not push the horn too much)

That dip isn't a real big deal because it's pretty narrow.  You aren't likely to hear it, except perhaps with sustained notes that hit it precisely.  Even then, the higher harmonics are at least as important for the perception of notes there.  Is the measurement you posted with just the sub playing or does it include the mains too?  A key feature to look at is how the mains and sub(s) blend through the crossover.

12 hours ago, Droogne said:

Not a detached house, but dont mind that  act like I do haha. I'll deal with the neighbours (pitchforks and all). I'll try to get my hands on a SPL mic to calibrate the UMIK.

Good luck with dealing with the neighbors.  Maybe invite them to join in once and a while, and maybe you can negotiate times to play it loud or something. 

[Droogne]

31 minutes ago, SME said:

The sub crawl approach works great if you're only really concerned about one seat location.  Just put the sub there, preferably propped up so the horn is at ear level and then test each of the different candidate locations.

Hahaha moving that 70kg horn onto my couch will be a struggle (but that way it would be at ideal position). The testing is only by ear, or would measurements also be useful? 

31 minutes ago, SME said:

That dip isn't a real big deal because it's pretty narrow.  You aren't likely to hear it, except perhaps with sustained notes that hit it precisely.  Even then, the higher harmonics are at least as important for the perception of notes there.  Is the measurement you posted with just the sub playing or does it include the mains too?  A key feature to look at is how the mains and sub(s) blend through the crossover.

Hadnt noticed till I saw the measurements, so I'm not worried. Good to know though. The measurement was including the mains. Those were crossed at 60hz. Problem I had, or noticed, was that I was able to notice the subs position (before I used the DCX2496 to EQ), which is why I lowered the crossover from 80 to 60hz, and put a 60hz cross(with the DCX) on the sub too (which I already moved up to 70hz). Don't think it did anything, so will probably get everything up to 80hz. My mains do 60hz and lower pretty well I must say so I could keep those there though. What would you recommend? everything to 80? PS really really love having a true EQ for my sub (instead of the one build in my AVR). I bring it down when watching movies, and pull it back up for music. 

31 minutes ago, SME said:

Good luck with dealing with the neighbors.  Maybe invite them to join in once and a while, and maybe you can negotiate times to play it loud or something. 

They have been very pleasant for now, no complaints! Have listened at quite high volumes too. Not for a very long time though (exams  ) , but will probably have to suggest something like that if I want to integrate some deeper subs  

[SME]

On 12/18/2017 at 3:58 PM, Droogne said:

Hahaha moving that 70kg horn onto my couch will be a struggle (but that way it would be at ideal position). The testing is only by ear, or would measurements also be useful?

Yeah.  Big subs get heavy.  Mine are probably ~100 kg fully loaded.  Definitely take measurements if you go through the trouble!

On 12/18/2017 at 3:58 PM, Droogne said:

Hadnt noticed till I saw the measurements, so I'm not worried. Good to know though. The measurement was including the mains. Those were crossed at 60hz. Problem I had, or noticed, was that I was able to notice the subs position (before I used the DCX2496 to EQ), which is why I lowered the crossover from 80 to 60hz, and put a 60hz cross(with the DCX) on the sub too (which I already moved up to 70hz). Don't think it did anything, so will probably get everything up to 80hz. My mains do 60hz and lower pretty well I must say so I could keep those there though. What would you recommend? everything to 80? PS really really love having a true EQ for my sub (instead of the one build in my AVR). I bring it down when watching movies, and pull it back up for music. 

If the lower crossover sounds better with the horn, then it's probably best to use it, but it seems like kind of a waste.  Have you tried crossing it at 90 Hz or 100 Hz?  How high does the horn play clean?  With all that capability on tap, I'd think about trying to run it even higher.  Other than my MBMs, all my XOs are set to 100 Hz, and it works great.  Some day I may run the front-wall subs up as high as the rear MBMs or even higher.

My experience is that hearing localization is often a kind of illusion.  What can happen is that your head is near a frequency response null in the room, and when that frequency is playing, the SPL in one ear is much higher than the other.  This can give the impression of directional sound, and it's natural to want to blame it on a subwoofer.  However, it may just have to do with uneven response in the room.

Right now my two MBMs, which are located behind my sofa, are running all the way up to 150 Hz.  This helps to provide better mid-bass fill-in for the left and right mains.  One would think they would be easy to localize that way and that I should sometimes perceive sound coming from behind or to the sides (depending on where I sit), but I don't notice them at all.  On the other hand, I used them in a previous configuration crossed at 100 Hz, and the response at the seats wasn't as smooth.  I actually perceived localization a lot more in that situation.