Tang Band Tang Band W8Q-1071F 8 X 12 box reccomendation

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I am moving this subwoofer into my big home theater in the basement and looking at placement options. I think I already know the answer, but it is it optimal to face a horn subwoofer so the throat is pointed up (towards the ceiling) in a corner? I am thinking that would not be good.

Permo, always good to hear from you. A while back I had a number of individually controlled drivers in various boxes. Something like 16 different drivers from 6 different manufactures. Each in their own uniquely designed cases, all with their own amp and their own channel, running through three 5.1 sound cards, into a single laptop running reaper. This allowed me complete control of crossover's, delay, fir, eq, etc. Plus I had a few mic's thrown into the mix for testing.

What this allowed me to do was test all kinds of scenarios. What I found is that if you run all of them at the same time, it's really loud. ��

Just kidding. Seriously, what I personally found is that if your running a whole lot of drivers, it seems best to face them all forward including the sub. Create a very large sound wall with lows on the bottom, mids in the middle and highs above.

With fewer speakers it seems best to move more towards highs facing up, mids forward and bass down. If using only a single full range driver, the best sound in most rooms seems to be with the driver facing up and the port facing down, with the speakers at least 2-4 feet (at least a meter) from the nearest walls.

None of this is scientific, just listening and then tuning in each of the many test scenarios. What I learned is that I am crazy... No really, that I have a very patient wife because all of this was done in the family room over a period of weeks. :eek:

Seriously, what I learned is that the more drivers you have, the less control you get of the sound stage, and that the lows like to live, well low to the ground, and that the highs love to be, well, high, where they can bounce around. None of this is really that much of a revelation based on how people have been building speakers for years, except in the case of the full range and three way drivers. Bass seems to work best if out in the room and facing down or if you have a lot speakers you are trying to match, as close to the other speakers as possible, and facing forward if the speakers are close to any wall. And always two subs, one on each side as close to the mids/highs as possible. Anything else gives you a lot of reflections that are really hard to tune away or know what is actually going on.

So that would be my starting point. Down depending on where your other speakers are and how many have and out in the room, or forward if the speakers are close to walls. Because as any good engineer will tell you, the best answer is it depends. And in my case anyway, I have the two very large tubes you helped me build facing forward right next to the tall ribbons out in the room away from the walls. I would have had them facing down, but this ended up not being so spouse friendly. I did try up as well, but lost all of the bass.

Since you are so good at designing and building tubes, you should try building/designing and sharing one for us that faces down with the option of facing forward. Maybe some kind of removable panel that slides either into the front or can be repositioned to the bottom. This would allow us to use them in either position AND make them at least somewhat spouse friendly. ;)

Let me know if my ramblings were not clear and I would be happy to answer any other questions.
 
Hi,

Thank you for your feedback, always nice to read.
Sealed subs are always a good idea but I prefer a single T-TQWT as main sub
together with a couple of smaller ( 15-20 L) lateral placed closed box subs.

Submitting a picture of a smaller T-TQWT using a favorite driver, the Wavecor
-SW178WA01 that provides IMO,IME outstanding SQ (Music use).

b:)

Love it!

I would like to get your take on the down facing / forward facing option I suggested to permo. Do you think that it is possible?

Also, I went looking for the wavecor and here in the states it seems a little hard to get. Any suggestions of other similar drivers that you like that would be pretty easy for me to get?
 
Love it!

I would like to get your take on the down facing / forward facing option I suggested to permo. Do you think that it is possible?

Also, I went looking for the wavecor and here in the states it seems a little hard to get. Any suggestions on other similar drivers that you like that would be pretty easy for me to get?

Oh, and I would like to get your take on group delay. It seems that it is really hard to create a T-TQWT with low group delay. Something about physics getting in the way.

When designing T-TQWT's, how does everyone go about reducing group delay so that it is not noticeable on the lower end? What are the tricks?
 
Hi permo and Uptime,

No time at the moment: please, revisit Post #123 in this thread: http://www.diyaudio.com/forums/subw...8-x-12-box-reccomendation-13.html#post2859029
Also, bjorno has posted frequently on group delay, basically the T-TQWT does not have a problem.

Regards,

Thanks so much Oliver. I understand it better now. Am I right in saying that group delay isn't really a problem because at the length of the quarter wave tube the signal is 90 degrees out of phase and so it reduces/cancels out the potential group delay?
 
Oh, and I would like to get your take on group delay. It seems that it is really hard to create a T-TQWT with low group delay. Something about physics getting in the way.

When designing T-TQWT's, how does everyone go about reducing group delay so that it is not noticeable on the lower end? What are the tricks?

Hi uptime,All

Been busy over the New Year..
At onset:I think Gldy is easy to handle for quarter-wave-boxes as long as the (sub) passband phase is smooth and stays within ~1/f and don't cause ripple when integrating with the main speakers.

In common rooms: Up to ~3 dB narrow-band dips can be tolerated below~150 Hz(more when (sub) LF Pitch actually is heard,i.e. when needing more than 3 cycles to be audible RT30(RT 60) typically> 200 mS(treated monitoring room) but watch out for peaks of similar size that are much audible when interacting with the onset of the Mains. Off-band ripple must (IMO) be suppressed at the origin of occurrence by using damping material or clever introduced bends....

Here are some of my Notes concerning( or closely connected) to this matter..

Here: An easy reading of introduction to Psychoacoustics:

http://kurser.iha.dk/eit/eaku/litt/Psychoacoustics.pdf

b:)
 

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Hi uptime,All

Been busy over the New Year..
At onset:I think Gldy is easy to handle for quarter-wave-boxes as long as the (sub) passband phase is smooth and stays within ~1/f and don't cause ripple when integrating with the main speakers.

In common rooms: Up to ~3 dB narrow-band dips can be tolerated below~150 Hz(more when (sub) LF Pitch actually is heard,i.e. when needing more than 3 cycles to be audible RT30(RT 60) typically> 200 mS(treated monitoring room) but watch out for peaks of similar size that are much audible when interacting with the onset of the Mains. Off-band ripple must (IMO) be suppressed at the origin of occurrence by using damping material or clever introduced bends....

Here are some of my Notes concerning( or closely connected) to this matter..

Here: An easy reading of introduction to Psychoacoustics:

http://kurser.iha.dk/eit/eaku/litt/Psychoacoustics.pdf

b:)

Wow. Thank you so much!

It is a very interesting read indeed. Some of the publications you reference I have read before, but most of it was new for me. I also completely read and re-read a few of the other related content and notes you have in there as well. I have not completely digested all of it yet, but I am beginning to understand our ears just a little better, and why I continue to be so fascinated about reproducing the low end properly. I of course love all properly produced content across the entire spectrum, but with good source material, proper delays and synchronization of content it does seem possible to create a completely new and immersive experience.

I would love to communicate with you one on one some time (email, private messages, etc.) It might just change the world and get us out of the dark ages of audio we are currently in.
 
I would like to echo what TB said here. Bjorno you are one of the most helpful individuals on diyAudio and your efforts deserve recognition and appreciation.

Thank you, You're a bad ***!:hohoho:

-Matt


+1 for sure. Thanks to him and and tb I have one of the most bad **** subwoofers around. I watched avatar (I know crappy movie) on blue ray the other day and I sat near the subwoofer. It moved my clothes when the ships where landing and stuff. For only using 200 watts of power it is amazingly effortless. I would love to build another someday!
 
I just wanted to provide an update. I have been using this subwoofer for over two years now and I think it performs better now then when I initially built it. I think the drivers are broken in.

This thing has a substantial amount of output for only using a 200 watt amplifier. I wanted to thank everybody that helped me again. I am also looking to do another project soon so keep a look out!!!
 
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