The making of: The Two Towers (a 25 driver Full Range line array)

Sorry to have been away for the rest of these discussions, I wanted to make sure I could see double today.

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View the data online, I'm pretty convinced the 26w would do everything you want and more. That is, if you're not shy about using some DSP.

If you're set to get it working using T/S parameters and no processing, it becomes a different kind of challenge. Especially inside the room. Throwing those woofers inside a sealed box should first be tested (simulated) to see the effect that has. I can't see it working well without some DSP.

Paradigm uses ARC processing, I've played with that in the past.

A first reference to the 26W: 26W-4558T00-II

Great stuff, and thx for the great input :p
I think ScanSpeak now :p

re pink
I would say not. Mark Kravchenko is a really good engineer that frequents these forums and likes to go to extremes to get extremely good results.

Need to think about these then, many choices now :D
But I wonder if ScanSpeak is a step up from these

Which you don't get with open baffle bass, unless physics are different where you live...

Guess what, even in Norway, Einstein is applicable.... and I am confident you are correct on the sealed subs vs OB :p
 
Of course, everyone has preferences, but physics is a fact and SPL is SPL, the air molecules don't care, it's not easy to get LF bass from OB but it's not impossible either, which is what seems to be being implied.

I used to dream about infinite baffle bass when I was a young kid, always figured that I would hack up a wall when I finally had a house that I could call my own. Sadly my girlfriend did not share that dream :eek:.

In fact she reminded me only a few days ago that these subwoofers will be the last addition to my Stereo setup. All I could think of, if she doesn't "see it" it doesn't count, right? :D
 
I used to dream about infinite baffle bass when I was a young kid, always figured that I would hack up a wall when I finally had a house that I could call my own. Sadly my girlfriend did not share that dream :eek:.

In fact she reminded me only a few days ago that these subwoofers will be the last addition to my Stereo setup. All I could think of, if she doesn't "see it" it doesn't count, right? :D

She obviously doesn't get it .... :p
 
I'm in the process of installing an IB in the corner of my room, thankfully it's only required cutting out a small section of drywall. I checked with a sealed sub that it would be ok there, got a surprisingly smooth response, just a ubiquitous 40 Hz peak.

Yes, easy to hide an IB array :) How about an IB DBA? :D
 
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Basically what I am looking for is to make a setup where total q is very low, because in my simple mind I believe that will be one of the required parameters that I need to get really tight bass with no overhead and no ringing, and well, that means expensive Scanspeak or Morel drivers, Scanspeak revelator subwoofers or Morel Titanium former line of subs....

The Q can be made to be made to be whatever you want within reason, by EQ'ing the rolloff to represent the same Q, or use a linkwitz transform. Wesayso's 30w has a Qts of 0.32 so anything above that can be chosen with processing.
Which you don't get with open baffle bass, unless physics are different where you live...

Having used both myself, here's some data to help explain why both sides might be right in their thoughts. It's all about volume displacement, below is a comparison of LX521 to my arrays, arrays (blue) have more Vd below 50Hz, LX521 (green) more above. The LX521 certainly went low enough but it had a prodigious amount of EQ and high xmax woofers. Both were displacement limited to 97dB at 50 Hz. If you put the LX521 woofers in a sealed box you get the red line.

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-------40 Hz peak.-------
Lol, my living room has a peak at 45Hz.
Your kitchen is bigger than my living room.:D


@wesayso: no pics yet unfortunately. Think of plain MDF bricks, stacked 2 high against the rear wall of a room, between two side walls. Total baffle size is around 3.00x0.75m as it sits. It was created for a much bigger space than my current one, but I just stick with it.
If the boxes were at least painted I would post a picture... They look like a first graders' project compared to yours.
 
I think that Paradigm Sub might be the one OPC referred to as trying to rip itself apart when wired in series and drivers sharing the same volume, part of the series parallel debate, not that it should be re-opened :D Maybe a consideration if trying to design something similar though.
 
Comparing open baffle vs closed/BR for bass freq is not as simple as fluid said. Because of the room!

Backwave of a dipole (even if radiation isn't perfect dipole) makes different reflection first nulls, distribution of room modes and there will be no pressurization below lowest room mode. Positioning of a dipole bass radiator in a room is trickier, distance to walls is more critical, and it also has effect in higher frequencies. Sideways modes will be easier.

Article On Dipole Subwoofer Placement

Here are articles of Gradient 1.5 which has special sideways dipole woofer
Gradient Helsinki 1.5 loudspeaker John Atkinson, November 2010 | Stereophile.com
Gradient Helsinki 1.5 Loudspeaker | The Absolute Sound

Personally I prefer closed box for lowest bass, two units so one can cross a bit higher and to distribute room modes. More subs will make room response smoother, but then xo must stay low. Cardiod subs might be good, but I don't have experience with them.
 
Comparing open baffle vs closed/BR for bass freq is not as simple as fluid said. Because of the room!
I didn't say it was simple and there was no attempt to take account of room or placement as that will vary.

What I showed was volume displacement which is the ultimate limiting factor for how loud a speaker can go all else being equal.

The slope for a dipole is much steeper so there is less output as frequency goes down, meaning more EQ, Sd and or displacement is needed to produce the same level of spl as a monopole with the same driver.

The point was to show that a dipole can be as loud as you want if you throw enough Sd and displacement, just like Stig Erik did, but if you don't it will drop off fast at the lowest frequencies which is why some peoples impressions of dipole bass might be confused by a less than ideal implementation.
 
There is a guy over here that made bass towers for his Adyton fullrange speakers, which basically contain Peerless TG9FD10-08 drivers. The subs are pretty huges sealed boxes where each contacin 4 ScanSpeak 32W/4878T00, with lots of eq; so a total of 8 13" drivers.
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Looking at distortion figures measured with REW, I believe it is pretty darn good ones, look at the numbers :eek:, looks like these drivers are completely unreal...
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