The quest for 20hz open baffle bass

[Leonidas]

Hi Freddi,

This only works with the PAP Neo woofers !!
However there is some more room for the FR drivers.
I did test the FE206e & FE 207 and they work VERY GOOD.
Seas FA22 is a NO GO !!

So woofers are dedicated !!
I tried the alpha's but they are not suited !!

So the Foster will work pretty OK.
Ze' ev (CEO PureAudioProject) did the Voxativ ac 1,6 and say he never enjoyed the VOX as much as with this XO

It's just very musical.
As you mentioned in previous post ; it's not only deepest fr. but stay musical at the same time.

 

[Leonidas]

The boards are manufactured by Mundorf.
Just saw that you do not have the latest version XO.
There is a coil added to "shave" the 10kHz peak.

If you need more info ; just let me know.

In my room : L 6,2 , C 33 , R1 5,6 , R2 2,7 and coil 0,22.
but you always have to tweak for personal taste & room anomalies.

 

[dave 111]

Nice subs Leonidas. Surprisingly affordable too. under $500 for 4 of the ferrites and under $700 for the neos if I read it right.

 

[CLS]

Other than the very good example mentioned in post #19, here is another ambitious build:
mfk-projects subwoofer

Simply put, without pressurizing the room, you got to have such unrealistic size of OB bass to get down there and get loud enough.

So I think dipole is an improper tool to do LF below 30. At least, it's a very inefficient way. That's the territory of IB or horn (in mega size).

Or, among all dilemmas, you can listen to the woofer(s) in very nearfield with real-world size baffles. It's much easier to get bass from OB this way. However, in general, it's drifting away with the proper 'presentation' of very LF -- it should be 'big', right? And it's difficult to design a large speaker for very nearfield application. It won't be small anyway.

Oh, this can't be a project of fullranger. So I suppose it's in the wrong forum.

 

[freddi]

hi Leon - - your neo version must be very nice and articulate - PAP's ferrite woofer is somewhat like the old Silver Iris 15 in resonance and qts but with somewhat more moving mass (and xmax) - I might try to fake something with my dormant Silver Iris 15 and 206 or 1772

 

[Pano]

Why do you want to get down to 20Hz? Is it the number that intrigues you? What do you expect to hear down there?

FWIW, my semi-open dipoles play down into the mid 20s. Lowest room mode is 8Hz. I don't think there is much music down there.

 

[Leonidas]

I'm a "bass-hunter" for all my live !!
Building speakers over 50 years now.
It's not : how low does it go , but HOW it goes low.

These A15 Neo woofers are the most important thing that ever happened to me.

For my way XO-ing , they are a must.

These are the only 15 inch (till now) that can coöperate with the DX3 !!

Just recieved the news that Ze'ev had good results (there is music and magic in the air) With the Wolf von Langa field coil units. Both with modded XO & Leonidas XO.

These are the most "musical" woofers ever for me.
So so remember , every thing is personal.

I just like deep bass but must be integrated as well.

I feel silly , working on a system 6x the price and ended up with a set of boards with NO back.

But that's how it is for me now.

If you like to feel the emotion of the performers instead of the (sub) lowest tones ; you should go this way !!

(And I'm having plenty bass ; the way it builds up and kicks me , WOW)

Starting With , for instance , a Fostex will give you the oppertunity to upgrade later to a Lowther . ore that FR unit "which is your thing" .
Choosing for Leonidas XO gives the possibility to re-adjust for different FR units and if moving to another place ; adjust for other room dimension & Rt etc.

I do hope I'm doing allright with English and you all get the message ??

sinc. Leon.

 

[freddi]

low bass extension can help reconstruct whatever room ambiance that's on a recording making the speakers "disappear"

 

[dave 111]

Quality bass is the priority. Musical and integrated is exactly what I am looking for and I'm not a hard rocker. I guess I just figured aiming low couldn't hurt. If I didn't hit 20 but had better bass at 30 and up because I dug a little deeper that was kinda the idea. Is the Neo worth the extra money and I assume these would sound fine on a plate amp for now? What do you mean by a Leonidas crossover?

 

[xrk971]

If you want quality bass, look at folded front loaded bass horns. They have sensitivities in the 100dB range, low low group delay, ultra low harmonic distortion since the cone hardly moves. The HD is so low and the group delay is so low, most people won't recognize undistorted bass since they are so used to hearing distorted and time-smeared bass from reflex boxes. Sealed has less GD problems but HD is still present at significant levels as massive cone movement (and big amps with lots of power) is required to effect bass with a sealed box.

 

[5th element]

Are you suggesting that, below the modal region of the room, a single monopole source will produce a flat response at all listening positions?

That is the idea although there will still no doubt be a lowering of output as you get further away from the sub.

Attached is a picture of how my subs perform in my listening room before any EQ is applied minus the LT and high pass.

As can be seen all three tend to the same at low frequencies, that is flat without room issues. IT appears that my room is modal a little lower than the 40Hz I mentioned before but that 40Hz spike is insidious as it creates and is responsible for one note bass. All three subs and both main loudspeakers excite it too!

FWIW, I managed 20Hz on OB. Just. It was a Beyma 15P1200Nd a side, with around 30dB boost at the bottom end, after my DEQ2496 had finished with it.
Sitting around 3m away, cone excursion was quite visible on the low notes. No nasty noises, but they are very good drivers that can handle being put in silly situations like that one. Peak power delivery was hundreds of watts, but listening levels were, at best, moderate.

Chris

That Beyma certainly looks the part. Nice amount of xmax and an absolutely crazy amount of movement available beyond that before damage. Certainly distortion will rise if you go beyond the 9.5mm xmax figure but at least the driver isn't going to crap out on you!

Getting 20Hz extension out of an OB isn't really the issue, I've done it myself. The issue is getting enough output at 20Hz for it to be useful for anything. By virtue of the Fletcher/Munson curves we really do need a lot of output down that low for it to be audible and to have any notable impact.

With my OBs I used them for a few movies and whilst impressive it wasn't exactly explosive. Having gone multiple subs though they really do shake things in the way you'd like.

From what I've read dipoles do not pressurise the room in the way that a monopole does due to all the out of phase energy present and that in and of itself changes the perception of 'boom', 'explosion' type bass that you usually feel as well as hear.

 

[dave 111]

If a front loaded bass horn has these qualities and can create great natural bass like an open baffle dipole and do it in a domestic listening environment then by all means give me a pointer to a suitable horn!!

 

[Leonidas]

For Leonidas XO : The Leonidas Crossover - PureAudioProject So far tested with : Lowther DX3 , Vovativ ac 1.6 , Fostex FE206 & 207 and last couple a days with the Wolf von Langa Field coil motor on a Lowther.
It's an adjustable / tweakable XO for a set of PureAudioProject Neo woofers and FR units.

 

[Leonidas]

I also tested several amps ; lowest was an Aurexx 2x2,5 Watt tube amp. Did it just for fun. Would not advice it for techno & heavy metal. Sounded decent on Norah Jones Miles Davis e.o.
My Copland 2x25 watt had more grip.

 

[Leonidas]

And , BTW , I Always try to create a system !! never glue the bass under the Lowther !!

 

[Overkill Audio]

open baffle is best for quality but not extension with SPL

Hi Dave,

I built a few open baffle designs, I used a Variable Path Length (VPL) baffle and sides to give an effective baffle width of 1.7 meters for the bass, which tapers down to700mm for the low midrange.

Using Beyma and Precision Devices 15 inch drivers, suspended on poly prop rope and lightly sealed with sorbothane gaskets and wooden dowls to avoid vibration being transmitted to the baffle, I got the best quality bass and low midrange I have ever heard....
I coulnt get the power/ extension / high SPL's I wanted for music, and nowhere near what I wanted for home cinema.

But, if you have the room and dont mind big ugly boxes out in the middle of the room OB is the best quality bass and low mid solution.

Hope this helps and all the best
Derek.

 

[dave 111]

Very nice Overkill, I've seen your variable path length thing before. What is that for again? How is it you weren't getting enough SPL out of that for music? Headbanger!

 

[Overkill Audio]

VPL

Hi Dave,

Yes I am a bass head...!
The thing with good open baffle bass and low midrange is that when its soooooo natural and low distortion you just keep wanting to turn it up....!
Its very addictive and you can see why Stig Erik got so hooked he went up to twelve 18 inch drivers!!!

As im sure you already know, the bigger ( broader and or taller) the baffle the more extended the bass.
Big baffles are ugly, so folks made narrow baffles with deep sides, effectively a folded baffle. In fact some guys actually use hinges and keep it narrow when not in use (or the wife is home!) and then fold out the "wings" for serious listening.
The down side of deep sides is nasty standing waves in between the sides, plus , a very deep notch or step at the frequency which corresponds to the wavelength of the total effective baffle width.

It comes down to the basic path length of sound travel where the back wave curves around to meet the front wave.

This tunnel resonance / baffle step sounds cuppy / muddy and unnatural.
So all a VPL is is a way to "stagger" the step ie Vary the width of the baffle, which in turn varies the path length of cancellation....VPL .

Hope this helps and all the best
Derek.

 

[dave 111]

You don't have to tell me about addictive! Have you messed with stuffing the baffle at all or is that not necessary? At this point I feel like I gotta give some 15's a try and still think the Prv's look like an easy way to get started. Who knows, I may end up liking a FLH better but the simplicity and goodness of what I've experienced so far makes this hard to pass up.

 

[xrk971]

The Kazba baffle is a type of VPL.