[Serbia]

I have plans to buy 2 Tempest X and to build push pull sub so I could get more slam. Can you advise me about box  or even better to give me a scheme how to make it. I plan to cut it to 100Hz and connect it to amp and that's it. What do you think about that? My goal is to feel that precise vibration as strong as possible rather than hear it(lower freq the better it is).

[fackamato]

What's the maximum box size? 50 cubic feet (1500 litres), tuned to ~12.7Hz (five 4" pipes 16" long) gives you an F3 of 12.5Hz , you'd need  a subsonic filter at ~8-10Hz though.

Build as big as you can. What about an IB? (infinite baffle), if you have a closet you can use, or an attic, go for it!

[Serbia]

That's sounds so complicated . I hope u understand what effect I would like to achieve. Something similar to the earthquake, actually woofers r invented that way in the 70's by simulating earthquake by sound. My friend built a sub woofer that consists of 2 Lamar 10" drivers positioned in a push-pull system face to face in a box. The earthquake effect was very strong but with lot's of distortion I guess since he used very bad quality drivers probably. When he played Madona's "Rain" you could feel a flat of vibration that was moving from little bellow knees all the way up to hair. I was in a sitting position and in front of me was a satellite receiver  with green LED diodes showing the channel number. Well in certain moments I've seen those LED diodes vibrating which is not possible. And I was thinking to myself for about 7-10 minutes how is that possible. The LED diodes didn't vibe my eyes did . Imagine a flat vibration parallel to the floor going up and down depending of the rhythm of the song. In Madonas song it was focused more on to my eyes and it stayed there for quite a bit but it was moving up and down with moderate speed and in some parts of the body stayed longer(like eyes and hair) than moved down trough chests and stomach to end in knees. I could feel whole my body and very strong as well. I didn't hear the sub so much as I felt it. The feeling is so beautiful that not only I want the same thing -  I WANT IT STRONGER AS MUCH AS POSSIBLE(of course in my financial limits). To clear one thing that flat of vibration was appearing only in some parts of the song not all the time(I think between song text 3x). So I don't really want to hear it rather to FEEL IT.       

[Serbia]

I just want to add this comment and I'm finished with describing one of the absolutely best feelings in my lifetime. It is like a narcotic that u get addicted on the first taking and I mean it literally! Once u hear it, feel it whatever u name it u will be after that whole your life, trying to get the strongest, the most precise hi-fi vibe that will bring you totally new dimension of sound - A PHYSICAL "TOUCH" OF MUSIC, MOVIE, GAME whatever you play. Sadness is that those tings costs a small fortune but with a breakthrough of new brands that will charge us "simple mortals" a price that we can afford and get something similar for a reasonable amount of money. I got no knowledge but I can judge by what I hear/feel. I'm sure Kevin perfectly understand what I'm trying to describe though words cannot fully describe the feelings that listener gets by being exposed to such vibes, slams I don't know how to name it. I'm sure that there is so much better drivers and box constructions that will provide feelings in the listener's body beyond wildest imaginations. I can hardly wait for advices and schemes how to built a sub according to my needs. Looking forward to reply and open to any idea and solution. Thanks for reading. 

[Kevin Haskins]

I just want to add this comment and I'm finished with describing one of the absolutely best feelings in my lifetime. It is like a narcotic that u get addicted on the first taking and I mean it literally! Once u hear it, feel it whatever u name it u will be after that whole your life, trying to get the strongest, the most precise hi-fi vibe that will bring you totally new dimension of sound - A PHYSICAL "TOUCH" OF MUSIC, MOVIE, GAME whatever you play. Sadness is that those tings costs a small fortune but with a breakthrough of new brands that will charge us "simple mortals" a price that we can afford and get something similar for a reasonable amount of money. I got no knowledge but I can judge by what I hear/feel. I'm sure Kevin perfectly understand what I'm trying to describe though words cannot fully describe the feelings that listener gets by being exposed to such vibes, slams I don't know how to name it. I'm sure that there is so much better drivers and box constructions that will provide feelings in the listener's body beyond wildest imaginations. I can hardly wait for advices and schemes how to built a sub according to my needs. Looking forward to reply and open to any idea and solution. Thanks for reading. 

I'm not sure I can relate to what you are describing.   It sounds like it should be illegal.   

Bass is actually pretty simple, but getting it to sound right in a room is another thing.    The room, the listener's position in it, and the location of the device/devices along with the design of the room all affect low frequency playback.   Also, there is a significant amount of upper harmonics that are in the upper bass & lower midrange that all have to come together to get what I consider as "good bass".     

I can explain to you how to get tons of low distortion clean output down under 80Hz but it takes more than that to reach that nirvana you are describing.    It is a manner of system design that takes into account the room, it's acoustics, signal processing and planning a lot of things.   It is just more complex than building a better subwoofer.

[Serbia]

Damn, can you at least start with the design that should direct me in the way I want to go. I want a box scheme and a speaker/speakers I need to buy. It's a step by step procedure. I am into the Tempest X, is that the right choice by your respectable opinion?

[Kevin Haskins]

Damn, can you at least start with the design that should direct me in the way I want to go. I want a box scheme and a speaker/speakers I need to buy. It's a step by step procedure. I am into the Tempest X, is that the right choice by your respectable opinion?

The Tempest-X is currently not available unless you are in Europe or Australia.   I have some updates coming on that driver so for the moment, it is a poor choice for a new project.

The Maelstrom is a great driver and you get plenty of output.   My favorite build is a 8 cubic foot box with a pair of the PR-18 passive radiators tuned to about 17-18Hz.    I'd power it with a big pro-amp (at least 1500W into 4-ohms)  and use the Velodyne SMS-1 for both the subsonic filter (should be around 17-18Hz) and room measurement & EQ tools.    You should have enough output in a reasonable sized room to make some people sick.   If you need more output than that, you can always build a second.   

Crossing over at 100Hz is too high for most applications.   You really need to keep the sub close to the main speakers for higher crossover points and the entire design and low-pass/high-pass filter has to be much more carefully designed and implemented in those situations.    I'd recommend keeping the crossover low, under 80Hz and preferably around 60Hz if you want a true subwoofer to integrate with main speakers placed elsewhere in a room.   

In my new Exodus Speakers (yet to be named) I'm designing them with a distributed subwoofer approach to get smoother in-room response.   The subwoofer module & main speaker will have a purpose designed crossover taking into account the phase and location of the main speaker, giving a perfectly well-behaved crossover.   The subwoofer is a fixed distance from the main speaker (only about 6") so that gives me very good control over cancellations between the main speaker and the sub.   It allows me to get the phase correct and really design a good crossover that is well behaved.     That is the kind of approach you have to take to get good results with high crossover points.   Otherwise your results vary significantly.

The distributed subwoofer approach gives you smoother in-room response also.  I'm working on a couple bands of PEQ for each device so that the in-room response is about as linear as can be achieved.    My "ultimate" setup would include something like this with distributed subs, and a couple big Maelstroms tuned low for the really deep stuff.   If you run the big boys only down under 40-50Hz they would help add weight and heft where the smaller subwoofers are less capable.    The distributed subs help keep 30-200Hz smoother and a couple bands of PEQ on each device allows you to really fine-tune the worst offenders.    I'd also add some limited bass trapping to corners & the front of the room.    I'd keep the top, sides and rear of the room relatively live.   

That is the kind of system approach I'd take.   You use multiple devices with deep bandwidth, some PEQ selectively, some bass traps in corners, and a relatively live room elsewhere. 

[Craig Treusdell]

I've experienced that type of bass several times although for some reason I can't recreate it. I remember each event very well
Once was 20 or so years ago in an SUV with 4 SoundStream SS8s in a ported box. Couldn't see anything!
Again around '96 in an SUV running 3x12" Earthquakes in a ported box with an AudioControl Epicenter (Are you out there Raife?)
Recently in an SUV with a SoundStream SPL 15, again ported.
Okay, I'm rambling.
So I would guess SUVs with high-tuned (>35Hz?) ported boxes with lots of THD (and thus additional higher frequency bass) produce this effect.

But how about in a house?

I finally felt this in a friends house using an SVS sub (2x12's with three pluggable ports I believe - not sure how many if any were plugged). My jeans at my ankle were moving, and no I wasn't standing next to the ports. Wasn't his dog either.

I have an original Tumult using PRs tuned to 16Hz powered by a QSC RMX 2450 bridged and wired in a 4 Ohm configuration, and can't come close to the SVS mentioned above in terms of chest pounding, body massaging bass. Even a pair of QSC HPR153 self-powered speakers have better punch/kick.
I guess my living room acoustics suck with 11' ceilings and multiple large open doorways. Running LinearX pcRTA shows some huge dips. Even tried the Tumult in a sealed enclosure with a Q of about 0.7 and produced the same shaped frequency response. Still similar shaped FRs in different locations in the room. It does shake the house good for music and movies though.

So Kevin (or anyone), what would be your guess as to why I don't have this same type of bass?
Could it be entirely the room acoustics?

I'm guessing this is what Serbia is looking for.
Me too.
And I want it clean.

Thanks

[Watson]

I just want to add this comment and I'm finished with describing one of the absolutely best feelings in my lifetime. It is like a narcotic that u get addicted on the first taking and I mean it literally! Once u hear it, feel it whatever u name it u will be after that whole your life, trying to get the strongest, the most precise hi-fi vibe that will bring you totally new dimension of sound - A PHYSICAL "TOUCH" OF MUSIC, MOVIE, GAME whatever you play. Sadness is that those tings costs a small fortune but with a breakthrough of new brands that will charge us "simple mortals" a price that we can afford and get something similar for a reasonable amount of money. I got no knowledge but I can judge by what I hear/feel. I'm sure Kevin perfectly understand what I'm trying to describe though words cannot fully describe the feelings that listener gets by being exposed to such vibes, slams I don't know how to name it. I'm sure that there is so much better drivers and box constructions that will provide feelings in the listener's body beyond wildest imaginations. I can hardly wait for advices and schemes how to built a sub according to my needs. Looking forward to reply and open to any idea and solution. Thanks for reading. 

What you're actually describing is a peak in the bass around the resonant frequency of your chest cavity. This gives you the strongest physical, visceral sense of bass, and is typically how a good dance club sound system is set up. Having flat bass out to close to 20 Hz will actually disappoint you if this strong physical sensation is what you're looking for. You may want two subwoofers, one tuned flat as low as you can make it go, and then one tuned with a strong peak in the 70-80 Hz range. If you can only afford one, go with the one with the peak. You'll be happier. And keep Q above 0.7.

[Kevin Haskins]

I agree with Watson.   It is typically > 30Hz where you get that sensation of overwhelming bass.   Cars are easy because you get so much free cabin gain.   The room is the biggest issue.   There are HUGE variables room to room so you can have a sub in one room, in a given location that just kicks ass.   You can take that same sub to another room and it barely is sufficient.   

I had a sub in college (back in the day) that could rattle the windows in our entire dorm.    The director had to come looking for the offender and expecting to find them on his floor walked the halls looking for the source of his rattling windows.    I was four floors up and we just had a kick-ass little concrete room that allowed for some incredible bass within that small space.   It also traveled through the walls (& floors) such that I could rattle everyone's door.   In that room you felt every note, heard every bass line and it was taunt and tight.   It wasn't one note it was the entire spectrum that was boosted out of balance with the rest of the system but we loved it.   

When I moved to a house I ended up looking for another sub because that one wouldn't do the trick any longer.   It was a real let-down because I thought I had the ultimate sub until I moved.   

[Serbia]

I had a stomach virus and was unwell . Thanks so much for advising me. The problem with the sound is that it is a relative thing, you need to hear it before you buy it and that's the problem. I would need a small fortune to test and get the knowledge so I could finally be able to get what I wanted in the first place. This forum helps a lot. So I'm ending with 2 subs, fine. First I'll get the one with the peak 70-80Hz to get sensation and after that the other one. Witch driver would be the most suitable for my situation. What type of box? I don't  want it to be too "loud", I like it stronger but more silent. I don't know how to explain . I want strongest vibration (cleaner as possible) and to hear it not too loud, I would like it more silent to be.   

[Kevin Haskins]

I had a stomach virus and was unwell . Thanks so much for advising me. The problem with the sound is that it is a relative thing, you need to hear it before you buy it and that's the problem. I would need a small fortune to test and get the knowledge so I could finally be able to get what I wanted in the first place. This forum helps a lot. So I'm ending with 2 subs, fine. First I'll get the one with the peak 70-80Hz to get sensation and after that the other one. Witch driver would be the most suitable for my situation. What type of box? I don't  want it to be too "loud", I like it stronger but more silent. I don't know how to explain . I want strongest vibration (cleaner as possible) and to hear it not too loud, I would like it more silent to be.   

The best place to start is doing some reading.   This is not a simple subject and you are looking for a simple answer to a complex subject.

Floyd Toole is probably one of the better choices for this topic.   He headed the research at Harmon and covers subwoofers near the rear of this book.    It will probably just confuse you more but there is enough information to help you make better system choices for subs and it is money well spent. 

http://www.amazon.com/s?ie=UTF8&search-type=ss&index=books&field-author=Floyd%20Toole&page=1

If you want the sweet and simple answer.    You need multiple subs and the ability to both measure the subs in the room along with complex equalization for each to get reliably good results.   It also helps to have an acoustics background or at least some mathematics so that you can make educated guesses about which room modes are caused by which room dimensions and how changing subwoofer/listener location can help alleviate a problem.     You need to be able to take measurements down to 1-2Hz increments and you need parametric equalizers with fine resolution to be able to treat things electronically.    Generally, the more subwoofers added the less the need for equalization although there are situations where fewer are better than more.   It really comes down the the acoustic measurements and there is no way to accurately predict these things just based upon room dimensions.    Room treatments are not always necessary but a good knowledge of them is helpful in treating certain problems.   That becomes even more complex though.   

So there really isn't a short and sweet answer.   Room behavior down low is the biggest barrier to getting good bass.   The subwoofer itself is the easy part.   

[Kevin Haskins]

Oh... one more thing.   Getting good bass over a range of listening positions is much more difficult than getting good bass at one spot.   If you are willing to design around a single sweet spot the situation becomes much less complex.        That would be my approach.   Optimize around one area and make your mother-in-law sit in the bad seat. 

[Serbia]

I'll take your advice and make a sweet spot for myself . My room is not very big, kind a small 3,5m x 5m .Your advice for "sensation" effect is still Exodus 18" in a sealed box, if not which one with the peak of 70-80Hz like Watson described? One more thing before I start actually buying components, what to be the best amplifier for my needs in economic range, price/quality(I don't plan to spend too much cash, I mean there r amps for 5 000$- 100 000$ and I don't have that cash).   

[Kevin Haskins]

I'll take your advice and make a sweet spot for myself . My room is not very big, kind a small 3,5m x 5m .Your advice for "sensation" effect is still Exodus 18" in a sealed box, if not which one with the peak of 70-80Hz like Watson described? One more thing before I start actually buying components, what to be the best amplifier for my needs in economic range, price/quality(I don't plan to spend too much cash, I mean there r amps for 5 000$- 100 000$ and I don't have that cash).   

I'd budget for something like the Velodyne SMS-1 which will help you with room measurements and basically give you all the equalization tools needed.   The Maelstrom requires a LOT of amplifier power to use all it's capability.   I tend to recommend pro-amps because there just isn't any small plate amps capable of providing that kind of power.    A popular one in the USA is the Behringer EP2500 which is only around $300 delivered.   There are plenty of other choices further up the price scale that are much better quality.   I sell the Face Audio amplifiers which are much higher quality but over twice the price of the Behringer.    Another thing of note is that pretty much all the pro-amps are actively cooled.   They have fans so you either have to plan for remote mount in a closet or modify the fan to run slower so they are completely silent.   

With the equalization you don't need a peaky system.   Once you have control over the electronic side of the signal you can almost ignore the non-equalized output of the device.   You still have to be concerned with power limits, mechanical limits etc...   but you don't have to worry so much about the exact frequency response of the build.   After all, you can change it easily with the SMS-1.     Also, I wouldn't necessarily say that a peaky system should be your goal.    With the EQ tool you can play with it to your heart is content and pick your own response curve.    If you like it with a little boost within a range it is easy to dial that into the device.    I like relatively flat bass response and I think once you hear it, you will too. 

Get the book though.   That is the first thing you should spend your money on.    It won't give you an easy answer but you will have a lot better handle on what the trade-offs are and what the current research is concerning bass reproduction in small rooms. 

[Serbia]

 Definitely, I have to read a lot about sonic. I try to pick up everywhere I can, mostly I read on the internet. I'm buying this book and I hope I'll learn something from it.

 One more thing . So many strong sub woofers and amps, they must create a strong magnetic fields crossing each others in a room? How that effects on human body, is it harmful(what if you sleep in that very room - would that be like not recommended or dangerous)? 

[fackamato]

One more thing . So many strong sub woofers and amps, they must create a strong magnetic fields crossing each others in a room? How that effects on human body, is it harmful(what if you sleep in that very room - would that be like not recommended or dangerous)? 

I can't wait for an answer on this one! 

[Kevin Haskins]

Definitely, I have to read a lot about sonic. I try to pick up everywhere I can, mostly I read on the internet. I'm buying this book and I hope I'll learn something from it.

 One more thing . So many strong sub woofers and amps, they must create a strong magnetic fields crossing each others in a room? How that effects on human body, is it harmful(what if you sleep in that very room - would that be like not recommended or dangerous)? 

Nope....  no worries.   If you start attracting paperclips to your forehead or something I might get that checked out but a few subs won't give you cancer.   

[Serbia]

Finally I got the book - Sound Reproduction: Loudspeakers and Rooms !!! I hope I'll learn something from it. ThX Kevin, I'll be back after I read the book.