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Nearfield Ported MBM for Increased Mid-Bass Tactile Response

255K views 3K replies 147 participants last post by  holyindian 
#1 · (Edited)
Background

In the ULF thread and @coolrda 's Vibsensor thread, we've been discussing how different sub designs (sealed, ported, horn, etc.) can produce different tactile responses. When placed nearfield, these differences become more pronounced. Our focus has been largely from a ULF tactile response (TR) standpoint.

One of the theories is that ported produces more TR than sealed around the tune. I first demonstrated this in the ULF thread in this post:

Ported vs Sealed in my room

Recently, others have also done similar tests, but used a far more accurate measuring system with VibSensor:

@derrickdj1 example



His martysub is tuned to 20hz, and you can see in the above (scales were adjusted on images so that you can directly compare) that 20hz is much higher compare to his sealed Marty (plugged vents).

@MKtheater example



MK ported his IB setup, putting him at around a 7hz tune. You can see from the above how much the 10hz TR changed, even when he was running his sealed setup much hotter.

Within the spoiler below, I put together a much more detailed analysis of MK's example above:

Below is your IB Response superimposed over your ported response. They were superimposed so that the 85db and 95db lines were matched as that is the calibration point of each as you mention above.





You'll notice here that they are within 2db or so at 10hz. Remember, we are looking at 10hz because that is the frequency in consideration to test the hypothesis that around tune, ported produces more TR. Mk's IB ported setup is tuned to 7hz.

However, when MK took readings with the VibSensor, he took the reading for his sealed IB running 10db hot. When he did the ported reading with VS, he ran flat.

In the below graph, I increased the IB by 10db to compensate for running his IB hot.





As you can see, MK was running 8db hot (once you calibrate the two responses) when comparing FRs. Yet the Vibsensor shows drastic differences in the TR at 10hz...18db difference! :eek:

More evidence that TR can be increased without an associated increase in SPL, and that around port tune, ported subs produce more TR as compared to sealed.

:cool:

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If we assume that around the port tune there is more Tactile Response, then you could apply the same approach for LF frequencies, and more specifically mid-bass frequencies.

The reason I created this thread was to try out an MBM nearfield in support of this theory. :cool:



Based on the above, it appears that this mid-bass "chest slam" or "shortness of breath" effect is in the 50-100hz range.

I know HSU has an MBM offering and it's tuned to 50hz. But the problem with that design IMO is that the driver is downfiring. In order to get max Tactile Response, the driver and port should be facing the main LP. I've heard great things about the HSU though, I just think there might be a better solution.

I searched google, and really couldn't find anyone else that makes MBMs....BUT, if you think about it, an MBM is just a high tuned sub. Most PA subs have high tunes as they are geared toward music. With that being said, this opens up a lot more possibilities!

For my HT, I don't have a lot of space behind my seats as I already have two FV15HPs behind me as well as a second row.



So I do have size restrictions as well when thinking about this sub...it pretty much has to be no bigger (and preferably smaller) than the FV15HP...

So I found this $299 gem:

Behringer B1200D-PRO

Specs

It doesn't specify tune, but the FR is 60hz to 130hz. The frequency range is 45hz to 180hz (-10), although I'm not sure what that means...

It's only a 12in driver, but it claims to push 122db at 1m. This will be placed nearfield, so I'm not really concerned about it keeping up.

Also, I'm really doing it to see if it can be an improvement...I'm not currently lacking in mid-bass today by any means (2 FTW21s, 2 FV15HPs nearfield, Fusion 12 LCR, and Volt 10 for surrounds).

Thoughts? Any other subs or MBMs come to mind? Is this a solve for max mid-bass slam?


Testing Update 6-1-16: FV15HP vs 1200D


Subs:
Rythmik FV15HP - 15in Driver w/12hz tune
Behringer 1200D - 12in Driver, w/65hz tune


Distance:
10.5in behind the Main Listening Position


Content:
47hz Sine Wave


Level:
88db


Measuring tool:
LG G5 running VibSensor 2.0.0


Each sub was placed in the exact same location, and each was calibrated to 88db. I placed the LG G5 at the MLP and ran the tests.

The results are in....






As you can see, the 1200D has almost 2X the PSD and acceleration as the FV15HP at the same frequency and the same SPL.

Additionally, I don't believe this is at the tune of the 1200D. If VS was able to measure around 55hz, I believe the difference would be even larger... :eek:


Conclusion:


VibSensor does not lie...no subjectivity, just the data. Another example that "at or around port tune", there is more TR in the nearfield because of the increased Sound Intensity.


  • Sound Intensity is how we 'feel' sound and causes the Tactile Response (vibration) of objects
  • Sound Intensity (SIL) = Pressure (SPL) * Particle Velocity (PVL)
  • If SPL is held constant, and there is more Tactile Response than there MUST be more PVL
  • @3ll3d00d ran a model in hornresp comparing a 14hz tuned 12in sub vs a sealed 18in UXL that shows that ported designs do produce more PVL around tune (see image below)...many many multiples more in fact, extending about an octave
  • This means that a sealed design at 90db SPL will be less tactile that a ported design at 90db around tune.

The below graph (data points extracted from hornresp) show that the ported box produced much more PVL (10 TIMES more) compared to sealed around tune . And it looks as though the elevated PVL continues to about an octave over the sealed.





Given this, it's no wonder why all the examples above demonstrate that ported subs are more tactile around tune. :cool:



Research on Near Field and Sound Intensity

There's a lot of good discussion with regards to the near field and its benefits. I wanted to take a moment and define it based on what I've researched. Caveat: I'm an enthusiast not a scientist. :)

I originally talked about the nearfield almost 4 years ago in this post.

I will try and summarize it below and use the ISO 12001 definition of near field:

First defining Sound Intensity:

Sound Intensity (SIL) = pressure (SPL) * particle velocity (PVL)

Sound intensity has a direction as particle velocity is a vector quantity. This means it has a magnitude and direction. Pressure is a scalar quantity and has a magnitude, but no direction.

Sound Energy is a form of energy associated with the vibration of matter.

Sound Intensity is sound energy per unit time per unit area.

Sound Intensity is how we 'feel' sound on our bodies.

While bass waves are said to be omnidirectional (meaning we cannot locate the sound with our ears), the intensity of those waves are directional. This means we can feel where the waves are coming from in the right conditions. (e.g. Feel a NF sub with the driver pointed directly at your LP and then turn it 180 degrees away and see if you can feel the difference; the answer is yes.).

Now, on to Sound Fields...

Sound travels through various Sound Fields.

  • Far Field - Pressure and Particle Velocity are in phase. In this sound field, because they are in phase, when SPL peaks, so does PVL. Therefore, to understand Intensity, you just need to measure one of the quantities (SPL). When we measure SPL in the far field, we can expect that the Intensity will be the same regardless of the distance (e.g. 115db 25ft away will feel the same as 115db 40ft away).
  • Near Field - Pressure and Particle Velocity are NOT in phase (as defined by ISO 12001). This means that when PVL is at its peak, SPL is not. In fact, in the Near Field, PVL is greater than SPL in the Near Field (see page 2-15 in this paper). This is commonly referred to as "the near field effect". This means to get an understanding of Intensity (or how we feel sound) in the near field, we need to know SPL and PVL.
  • Near Field Region - ISO 12001 (see 1.1.2.2 in prior link) defines that a frequency is in the near field if it is within a wavelength. An 80hz wave is 13.7Ft. A 20hz wave is 54.8Ft. Given those lengths and the placement of our subs from the LP, most bass waves in the typical home theater room will be considered in the near field; meaning to understand Intensity or how we feel sound, SPL measurements are just not enough. We also need to understand PVL.
  • The Very Near Field It is the sound field that is very close to the source (see page 2-16 in prior link) where it behaves more like an incompressible fluid. This means there is very little SPL, and mostly PVL. The paper describes that this region occurs when the distance r from the moving object (speaker cone) is much smaller than both the wavelength *and* the object dimension L (eq. 2.36), which in our case would correspond to the driver diameter. Being that these ULF frequencies are much greater in length than the typical subwoofer diameter, the very near field would be the driver diameter (15in, 18in, 21in, depending on sub).

What does this all mean in practice...

The majority of sub frequencies in our HT's exist in the near field. This means that just understanding SPL is not enough to understand Intensity, or how we 'feel' sound.

Sound intensity is dependent on distance. The closer to the source, the more intensity you will have. It is also directional.

In the Very Near Field, the physics starts to enter fluid dynamics and starts to behave differently than the near field. It is said that this has high levels of PVL in this field relative to SPL.

To optimize (have the highest levels) Intensity:

  • Put the sub as close as possible. You'll get additional Intensity if the proximity of the LP is less than the driver diameter of the sub.
  • Use ported, horn, bandpass, etc.; anything with a vent. Hornresp has modeled particle velocity, and the models show increased levels of PVL compared to sealed in the near field. However, what it does not model is the behavior of the Very Near Field.


Sources:

https://www.bksv.com/media/doc/br0476.pdf
http://www.who.int/occupational_health/publications/noise1.pdf
http://www.microflown.com/files/media/library/books/microflown_ebook/ebook_2_sound_and_vibration.pdf


Measuring Sound Intensity:



1st - Microflown Acoustic Camera




2nd - Sound Intensity Mapping of a Speaker



3rd - Low Frequency Mapping of Sound Intensity of Speaker/Subwoofer

 

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#2 · (Edited)
Commercial and AIY MBM options​

Behringer B1200D-PRO





@Marc Alexander produced the below close mic response with the different configuration settings for the 1200D:




As you can see, it looks like the tune is around 65hz. Adjusting the 10db boost will change F3 depending on what frequency you set it at.


Yamaha DSR118W Review by @giftedmd $999 street price







PartExpress Assemble it yourself option



This box can be paired with this driver. It will also need an external amp.




Nearfield MBMs in the Wild​


Thanks to @Brazle for sourcing these:

I've been running my subs nearfield behind the couch for about a year now with MUCH success - best location for my subs in the whole room. I added the test MBM about 2 months ago.



As you can see they are all very close to the back of the couch and the sound (and feeling) is exactly what I'm looking for. I've been following the VibSensor & MBM threads for a while and this setup behind the couch is pretty common, especially where the goal is to increase Tactile Response which is one of the things I'm looking for.

I've gotten a lot of inspiration from those threads and from my own personal preference and research that have led me to this design.
Many have had success with setups similar to what I'm building (most with separate components though).
Here are some examples of setups I have seen and used as inspiration

1. @lz7j (these are run facing the couch with the ports at chest level)


2. @More is Better (there is some distance here between the couch and the drivers, and the drivers extend above the couch with most others don't, but I believe this was just temporary)


3. @Raylon


4. @raynist


5. @SBuger (new & old)


 

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#627 ·
@Marc Alexander produced the below close mic response with the different configuration settings for the 1200D:




As you can see, it looks like the tune is around 65hz. Adjusting the 10db boost will change F3 depending on what frequency you set it at.


Behringer B1200D-PRO



My first set of measurements may not have had Audyssey disabled. Here are new measurements including close mic (1cm from grille) measurements. I also added measurement for +10dB boost @65hz. The mdat with all measurements is also attached (zipped).

How do we interpret the close mic measurements? Is the port tune actually @ 50Hz vs 65Hz?
@dominguez1 please update the first post as appropriate.
@dominguez1 please update post #2 with the more recent measurements.

http://www.avsforum.com/forum/showthread.php?p=46716817
 
#3 · (Edited)
AVS member eng-399 built some MBM to go behind his second roll of seats. Next month I will demo them at the local gtg. He may be someone to talk to if you are interested in a cheap build. I think the drivers were around $ 60 for the Infinity 1260. Space was also an issue for eng-399. http://www.avsforum.com/forum/members/8500266-eng-399.html

Is it cheating to use some TT's for the mid bass slam, lol.
 

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#5 ·
Yup, I've seen those beasts...they look amazing.

I'm sure those are killer...but they are sealed. Need to try the ported variety for this test. :)

TT's for mid bass slam? Maybe...do you have the hooked up behind your back? That may work!
 
#4 ·
@dominguez1 - I'm currently experimenting with "MBM's" in my 8 x ported setup (4 x 11ft^3/17hz with HST18's, 4 x 7ft^3 avg/18hz-20hz with HT18's nearfield) and Fusion-15's in 4.6ft^3 towers for my LCR's on crown xls1500's. I recently built 2 x 6.5ft^3/30hz cabs and used the Dayton PA-460 with 325w rms/driver... I've set them up farfield with the hst18's, 12' from MLP and my setup is as follows:

General XO 120hz
hst18's, hpf 17hz, lpf 50hz
ht18's, hpf 25hz, lpf 80hz (anything higher caused localization)
pa460's, hpf 30hz

My system has never sounded and felt this amazing. I gave up 2 x hst18's for the pa460's as I didn't have enough space... they're that good in what they do.

I still plan on trying the pa460's on the lower tuned nearfield boxes ala VBSS. It's in the center of the room and is in a 20hz deep null, so I have them hpf at 25hz to save amp power.

@rhodesj has already modelled the 3 drivers in a 6ft^3/25hz box. "Red is PA460 with 400W, blue is the HT18D4 with 900W, and green the HT18D2 with 900W."


Above 40hz, you should see 2-5db more in output with the PA460's. $90 for the driver + $50 for the box and a $160 inuke1000dsp for both.




My only concern with the B1200D is the limited bandwidth as a nearfield sub... unless you plan on integrating it like a true MBM
 
#6 ·
@dominguez1 - I'm currently experimenting with "MBM's" in my 8 x ported setup (4 x 11ft^3/17hz with HST18's, 4 x 7ft^3 avg/18hz-20hz with HT18's nearfield) and Fusion-15's in 4.6ft^3 towers for my LCR's on crown xls1500's. I recently built 2 x 6.5ft^3/30hz cabs and used the Dayton PA-460 with 325w rms/driver... I've set them up farfield with the hst18's, 12' from MLP and my setup is as follows:

General XO 120hz
hst18's, hpf 17hz, lpf 50hz
ht18's, hpf 25hz, lpf 80hz (anything higher caused localization)
pa460's, hpf 30hz

My system has never sounded and felt this amazing. I gave up 2 x hst18's for the pa460's as I didn't have enough space... they're that good in what they do.

I still plan on trying the pa460's on the lower tuned nearfield boxes ala VBSS. It's in the center of the room and is in a 20hz deep null, so I have them hpf at 25hz to save amp power.
Wow, based on your ported setup, your room has to be very tactile! You should consider adding some sealed into the mix so you can get those bottom octaves.

I'm not a DIY'r unfortunately...don't have the time. But the PA460s do sound amazing. Was there a huge difference compared to the HSTs for mid-bass?


My only concern with the B1200D is the limited bandwidth as a nearfield sub... unless you plan on integrating it like a true MBM
Yes, definitely plan on integrating it. My HT room will be somewhat unique in that I'll have the low tuned FV15HPs nearfield, as well as the Behringer 1200D nearfield as well. It could be an integration nightmare...but we shall see.
 
#8 ·
I guess using a MBM is an individual thing after hours of listening to your system. First, what is your goal? MBM is rough 50-250 Hz but, could cover 35-600 Hz. There can be holes caused by room modes. Also, subs tuned low will suffer the higher up you go in the passband. Two questions come to mind, how well is auto EQ at correcting these problems and how are the rest of the speakers in the HT doing in the midbass region?

TT's are not intended for midbass but, I mentioned them since the ULF thread has a major focus on TR.:) Are there benefits to a MBM, sure. Dom mention using a ported enclosures in the nearfield in keeping with the TR focus. The trick is to integrate all of these different XO regions. The goal as I see it is to for more dynamic and a certain bit of headroom. That is one thing that suffers using large subs nearfield. The proximity of the low bass can muddy the midbass. Hopefully we will have some MBM at the upcoming gtg to evaluate.

I have not given much consideration to MBM and space is a problem. This is just another reason for running speakers set to small in the HT is good for. It increase headroom for the midbass from the other speakers in the HT. In the end, the rabbit hole keeps getting deeper, lol.:eek:
 
#15 ·
@dominguez1 Just to add a little info about the HSU MBM, I had one for a while and it most definitely had awesome mid bass - sharp, fast and punchy. I currently run a FV15HP with driver as close as possible to my back and is spectacular for mid bass slam IMO. I tried an MBM and used it the same way with the driver facing right into my back (pretty much touching the back of the couch). The FV and the MBM felt almost identical in that 50-80hz region (my crossover is set to 80) with the difference of the FV continuing to play on down to 12 hz or so.

It looks like you already ordered the other, but you may want to give the MBM a try and all you would be out is shipping if you didn't like it or just wanted to test. Keep in mind that you can take the spike feet off and lay it on its side to get the driver facing into the couch and as close as you want it. Also you can plug the port to seal it as well. That might be real handy as well to do your testing :)
 
#16 ·
Very cool @SBuger . Thanks for the feedback!

That was my experience with the fv right behind my lp as well. My hope is that because this behringer 1200d is ported and tuned around 50-60hz, that it will even have more slam than the fv.

I looked at the hsu, and was really looking for a solution where both the port and the driver were facing the same direction. Its my belief that the sound intensity generated around port tune is greater than the sound intensity generated from the driver alone. That's why we've seen more tactile response from the ported vs sealed tests I cited in the first post.

Additionally, ported vs sealed aside, what a great alternative to the hsu mbm if it works. I think the hsu runs at 599, whereas this 1200D is only 299. Quite a bargain to me if your focused on this narrow band 45-150 or so. Perhaps a cheap and very effective solution for those craving the mid bass slam.

We shall see!
 
#18 ·
I decided that I wasn't going to touch my existing FR, and just add the 1200D into the fold...and hope for the best. :eek:

Reason being, I wanted to be able to do some AB testing to determine if I liked it or not.

It always takes quite a bit of time to integrate my FV15HPs, FTW21s, and Audessey. My EQ system is a pair of 2 band PEQs from elemental designs (eQ.2). They are effective especially with audyssey doing the majority of the work, but it takes time to integrate them to my liking (I want certain frequencies amplified by the nearfield FVs and certain ones by the FTWs).

My FV15HPs are tuned to 12hz, the 1200D is tuned to 50-60hz, and then I have my sealed FTW21s.

I wasn't expecting them to integrate all together by leaving everything as is, but this was more about Tactile Response that a better FR. If I like the TR better, than I'd go back to the drawing board and try and integrate all 5 subwoofers.

Here's where I landed just by inserting the 1200D, and adjusting the setting on that and keeping my other EQ settings the same:



Red is my FR before, and blue is it after.... :cool:

Who knew! It literally integrated right in! :D It probably helped that I had a rising house curve before, and this flattened it out, but still...no phase problems at tune, it just filled the gap to make it flat. This probably saved me a half day of EQ'ing all these together.

I haven't done an AB comparisons yet, but first impressions are WOW! Lots more slam and TR! It certainly reminds me of when I had my FV15HP directly behind me. I'm amazed that this little 12in sub can keep up, but it definitely can...even with it's tiny footprint (14x17x16).

More to come, but so far I'm impressed...
 

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#21 ·
I watched In the Heart of the Sea last night with the 1200D as an MBM. Definitely makes a huge difference in Tactile Response! In fact, it might be too much! :eek::eek: I can definitely feel it in the chest more...at some points sort makes your heart race a bit it seems.

It definitely added a new dimension to my HT, and seemed to blend very well from a TR standpoint with what my FVs were doing. I also did some AB testing, and while my FVs can get close to replicating the TR (remember they are not right behind the LP), they can't quite replicate the TR with the 1200D right behind me.

I've also got all new vibrations I need to take care of in the room because of this little MBM...that was also a bit distracting when watching the movie.

It's funny, I've been so focused on ULF that past 3 years, it's interesting to try and maximize LF! :cool:

The true test is to watch a movie that really not action based, and see how it handles that. A pet peeve of mine is to have too much LF or ULF mated to screen action that's not really calling for that; for example, a door slamming or bass guitar riff, etc.
 
#23 · (Edited)
Sounds like you got the tactile response you are looking for! I'm jealous! I am very interested in the details of how you have this all set up.

IE.. -? receiver dual sub out to dual PEQ,
-set LPF to 45 HPF to 80 for 1200D,
-set HPF to ? for FTW 21
-set HPF to ? for FV 15HP
-Settings on each sub set to ?
-1200D placed right behind MLP
-FTWs placed in front corners?
-FV15HPs placed in rear corners/ nearfield
 
#25 ·
The sub is around a foot away from the mlp. Gain is at the 10 or 11 mark, and right now the 10db boost is on between 40 and 50hz or so.

These are the dials I used to get them integrated the best without touching current eq settings.

Its funny, compared to my other subs this could be classified as "cute"...but it really packs some heat! I can't believe it keeps up.

And for 299, it's a steal for a compact mbm.
 
#28 ·
Great question! The short answer is, given my EQ rig, I'm pretty limited once Audessey is done. This is the challenge when integrating sealed and ported, and then tweaking after Audessey...EQ tweaks vary. A increase in one band, could cause a decrease in another band...so it becomes a trial and error thing. It can definitely be done as you can see from my FR, but it doesn't behave how you think it should and just takes more time.

The real question (which I do plan to test) is if there is more TR from this MBM compared to the FV at the MBMs tune around 50-60hz...more to come on that, but will probably be a couple weeks until I perform that test because of a busy non-avs schedule. :)

Right now, all I can say is that this 1200D is a very effective and crazy affordable MBM that works well in my setup. I still need to determine if it's more effective that the FV in the same position.
 
#29 ·
I can also attest to the benefits of a MBM. I have been running an HST-18 and HT-18 in 4ft^3 sealed cabs and recently sold the HT-18 to upgrade to the UM-18, but it is out of stock for several months. So I ordered a PA-460 pro audio driver for $89 that is 98 dB efficient. Dropped it right in to the 4ft^3 sealed cab which is too large i.e. not ideal and powered it with one channel of my Inuke6k with no filter, just running it full range. It integrated will with my HST-18 and added very substantial mid bass kick. In fact, I demo'd it for my wife at reference level with music and she made me turn it down. She had an anxiety attack and said she did not like it. That it was too "sharp". I was like, huh? So she rephrased: "It's too punchy, feels like I am being kicked in the chest". Victory. Seriously though, the mad bass slam was too much for her and she became very distressed....took about 15 minutes for her to relax or calm down from it. So music volume limit with her is now about -15, but alone, reference level rocks hard. I think this combination will be very difficult to beat, but at this point I still have the UM-18 on order. I am considering building a 4 ft^3 dual opposed sealed cab for PA-460's to use permanently as my 2nd sub. Can only accommodate two total in my room, and the HST is very solid by itself down low in my room.

I can tell you that the PA-460 produced sine wave sweeps up to +10 dB above reference running hot with no compression above 40 Hz. When I get time I would like to compare sweeps between it and the HST with the power I have available.
 
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#1,918 ·
So thats what abusing the wife is like? LOL

I'm debating what to do with my tactical response situation. I have svs dual pb13s on concrete slab in open floor plan front of screen that is 6 feet apart and about 13 feet from my MLP. Debating whether to add another pb13 near field or crowson's or do cheaper subs behind or beside the couch. I still have my Axiom EP500 sub that is not really doing anything but sitting in another room that I have thought about adding to the theater. Its pretty powerful for what it is, but its not powerful like the svs pb13 and not sure if its ok to mix or keep all subs same in one room. What are your thoughts?
 
#31 ·
I dig all the Behringer gear. It just works. Got a friend that used to DJ that lends me his very nice rig when needed. 4xB212 and 2xB208's and they sound fantastic even with orchestra and classical music.

Ok, so this thread starts out with a bang. You got Derrick and MK's graphs working, detailed explanation, things are rocking. And you know how much I'm a sucker for pics and graphs. Don't know why but it just is. Anyway things are flowing.......right up to Post#18:eek:. What is that? Is that graph laid on its side? I don't get it......uh.....sigh:eek: oh........I see now.....frequency response(getting magnifying glass to verify I read correctly). Huh? Stupid computer:mad:, why did it redirect me to another thread about frequency response. Now I gotta go find that cool thread about MBM TACTILE RESPONSE.

Bro, your killing me:D.
 
#32 ·
I have a HSU MBM 12 MK2 with two Rythmik F15 HP's in a 2000 cubic foot dedicated basement home theater. The bass in my theater is stunning. It took some creativity and a little work to get it all set up right but I will share a little of what I did to help anyone out.

First off, an advantage of the Rythmik subs is they have a built in switch that will give you a 50hz 24/db crossover which perfectly matches the hsu mbm rolloff.

I use a hybrid Geddes subwoofer placement approach. So here is how I have them set. One subwoofer is on the front wall between my center and main. It is setup to handle all frequencies from the avr crossover down to 20 hz. It is plugged into sub one on my Pioneer Elite SC99 receiver.

Next I have another Rythmik in the opposite back corner set up to only handle LF bass below 50hz down to 20hz. I have the MBM placed 1 foot behind my seat very nearfield. It is gained matched to the rear subwoofer. The MBM plays from avr crossover (set at 80hz) down to its natural rolloff of 50hz. I plug the rear sub and the MBM into the AVR sub 2 output via a y splitter.

I run MCACC Pro, and it sets proper delay, and levels and eq to the subs and other speakers.

This is how I have basically done it. So how does it sound? Freaking amazing. Downright scary sometimes at the seat. Does not distract you from movie just adds that killer mid bass punch, and evens out the room response so you get great low bass as well.

Something important to make sure you do properly is gain match the mbm with the sub I use test tones at 80hz off of sound doctor setup cd.

That is it. I hope people find this helpful.


Sent from my iPad using Tapatalk
 
#33 ·
I never had better midbass than my twin, front loaded, folded horn, pro audio 18's. They could really hit that chest. They were big and ugly but cheap! I should integrate a pair into the setup.
 
#39 · (Edited)
Quick update:

Had 15min to get some more impressions of this little guy today. Watched TIH, University scene. Definitely more impact and slam compared to without it. Ran it at reference +5 hot...no sounds of strain at all.

Also, this was the first time I listened to a scene beside the MLP...WOW! Midbass is WAY more pronounced compared to off. Compared to the MLP, the side seat improvement is far greater! I've always had trouble replicating the TR to these side seats compared to the MLP, and this definitely gets them closer...especially in the midbass region.

Wasn't expecting that at all...stoked about that one!

The 1200D didn't really improve the sonic cannon scene...which it shouldn't as those cannons are centered around 14hz or so. When I remember back when I had an FV15HP directly behind my MLP...this was by far the most tactile that scene had ever been.

It tempts me to move the FV back behind the MLP again just to see...but I remember why I did that in the first place. The side seats were such a downgrade from a TR perspective when compared to the MLP. I'd rather make some tradeoffs for MLP TR, to get a more even TR experience across all seats.

Back to MLP impressions...it's really blending very nicely, especially from a TR standpoint. IIRC, when I had the FV back there it seemed to be too heavy in TR (almost too pronounced), but now with the 1200D back there and the FVs behind the side seats, I seem to get a good blend of ULF TR and Midbass TR; one doesn't over power the other, which I seem to remember having trouble with when the FV was behind the MLP.
 
#40 ·
Nice discussion! I read through it and decided to try two DIYSG mbm's nearfeild, in the flat pack front ported enclosure. Even tough they are ported and my main subs are sealed (IB) the experience is much better! I am not having trouble integrating them. I am so glad I did it, so thanks for the info guys and the positive experiences!
 
#41 ·
Very cool! Congrats!

I was looking at those DIYSG MBMs...might have attempted it if the 1200D wasn't so cheap, and perfect size for my setup.

I watched The Big Short last night...not a bass movie for sure, with this MBM behind me, the music hit HARD...sort of distracting really. I'm going some scenes without the MBM to see if it's just the movie...

Anyone else watch that movie? Did you find the midbass hot in that one?
 
#43 ·


Here's a shot of my FVs flanking the MLP. They are not directly behind the MLP, but directly behind the two sections beside the MLP.

The 1200D now sits between the bar stools, directly behind the MLP.

The FTW21s are in the corners in the front of the room:



In the above pic, the Left and Right Fusion 12s sit on top of the FTWs.

I just got done playing The Big Short without the MBM...it felt a lot more natural with the screen action, whereas with the MBM, it sounded great...if I was just listening to music and not a movie. With the movie, there was too much TR...

Hmmm...may have to do some tweaking. I personally like finding an EQ setting that works for everything, all the time, and I don't have to adjust.

Anyone else watch The Big Short and thought at times the music had too much TR?
 
#44 ·
Thanks Dom for starting this thread, it's great and I've learned a lot. My quest is for more mid bass punch so now I'm thinking hard about a near field MBM.
 
#45 ·
Awesome...glad its helpful. That's the goal. :)

For 299 and free shipping from amazon, this 1200D is a no brainer to give it a go! Its a very small foot print, and tuning is right at the mid bass frequencies.

Its a pro sub, so you'll need the proper cables...but those are pretty cheap.
 
#48 ·
Do multiple 18s cost more than 299? :D

Point being, the 1200D Near field is a cheap solution to try...and you're only out $25 or so for return shipping if it doesn't satisfy.
 
#49 · (Edited)
The MBM's I've experience have a very, shall we say sharply defined kick to them. I don't want to say an 18 can't do that as there's ones that do. Certainly parameters have their say in the matter but I think extension, LF cutoff too plays a role. I don't believe in a smaller driver being faster, but if a sub is hpf'd we perceive it as being faster as we're not hearing or sensing LF/ULF aspects. Whenever I've moved the hpf up or down on a speaker it gives the illusion of quickness changing. When done correctly,there's advantages to specific bandpass drivers. You could say it specializes in its specific bandpass that it was made for(Maximus 12 comes to mind).
 
#50 ·
What I have enjoyed so far about having mid bass modules nearfeild is this. They don't seem to really effect the overall sound in the room, that is a positive for me personally. It just adds a tactile feel that is hard to describe. Because they are so close, I set mine up to be a few db's less then my main subs, and I can't localize them, but the feel is awesome. And even though the boxes are tuned to 35 Hz, they seem to extend much lower. I took my two buttkickers off my theater chairs and put the MBM's back there, and I like the MBM's better. Just my $0.02. I'll probably use both though once I get around to it. :smiley:
 
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