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

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Hi All, I have been lurking on this site for a while and feel it is time to ask for some input.

I have two tang band 8 X 12 drivers with the following specs.

Specifications: • Power handling: 250 watts RMS/500 watts max • VCdia: 2" • Impedance: 4 ohms • Re: 3.2 ohms • Frequency range: 27-200 Hz • Fs: 27 Hz • SPL: 88 dB 1W/1m • Vas: 2.49 cu. ft. • Qms: 4.6 • Qes: 0.36 • Qts: 0.34 • Xmax 12 mm • Dimensions: Overall diameter: 8-1/2" x 12-1/8", Depth: 5-3/4".

I have modeled a 6.5 cubic foot slot ported enclosure tuned to 28hz that is essentially flat down to 25 hz. I am satisfied with the design but I don't get much gain from it. My problem is that I only have around 200 watts RMS available for the system so sensitivity and gain are very important and this design is lacking in those departments. Can anybody reccomend a solution with response below 30hz that could offer me a nice increase in sensitivity to make the most out of my limited power?

6th order band pass
Tapped Horn? (modeled up some, but they are HUGE!)

thanks much folks
 
Hi All, I have been lurking on this site for a while and feel it is time to ask for some input.

I have two tang band 8 X 12 drivers with the following specs.

Specifications: • Power handling: 250 watts RMS/500 watts max • VCdia: 2" • Impedance: 4 ohms • Re: 3.2 ohms • Frequency range: 27-200 Hz • Fs: 27 Hz • SPL: 88 dB 1W/1m • Vas: 2.49 cu. ft. • Qms: 4.6 • Qes: 0.36 • Qts: 0.34 • Xmax 12 mm • Dimensions: Overall diameter: 8-1/2" x 12-1/8", Depth: 5-3/4".

I have modeled a 6.5 cubic foot slot ported enclosure tuned to 28hz that is essentially flat down to 25 hz. I am satisfied with the design but I don't get much gain from it. My problem is that I only have around 200 watts RMS available for the system so sensitivity and gain are very important and this design is lacking in those departments. Can anybody reccomend a solution with response below 30hz that could offer me a nice increase in sensitivity to make the most out of my limited power?

6th order band pass
Tapped Horn? (modeled up some, but they are HUGE!)

thanks much folks

Hi permo,

Here is a simulation using two series connected Tangband W8Q-1071F in a T-TQWT that should not be driven with input powers above 200W Rms:

The design challenge is to provide enough of clearance behind the driver magnets...

b:)
 

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Wow, now I can see it. What kind of enclosure is this? It looks like the volume is workable for sure and it looks great. I can see the basic design, but all I get is L23......what is L12, L34..etc..etc... What driver configuration do I pick in hornresp? Clearly not a tapped horn..but looks AWESOME. Heck, I can start cutting wood tonight if I can figure it out.
 
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Wow, now I can see it. What kind of enclosure is this? It looks like the volume is workable for sure and it looks great. I can see the basic design, but all I get is L23......what is L12, L34..etc..etc... What driver configuration do I pick in hornresp? Clearly not a tapped horn..but looks AWESOME. Heck, I can start cutting wood tonight if I can figure it out.

Hi permo,

Here is a picture that might help:

PS: You can export the enclosure dimensions in HR by clicking on 'file' at the schematic diagram screen: Example in th picture.
 

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In my limited understanding and experience, there is no free lunch on this sort of thing. You can either play deep or have efficiency up higher. Playing deep with decent efficiency requires more driver surface area.

With your current drivers I came up with the following:

A 6th order bandpass with 2ft^3 @ 65hz and 4ft^3 @ 35hz will give you over 94db@1w@1m efficiency from 40-80hz, but will not be playing below 30hz and is basically limited to the 35-90hz range. It would deliver better efficiancy from 35-90hz than your current model by as much as ~4.5db across most of it.

A 6th order can be used to replicate the rolloff of your current model, but the efficiency gain is only about 1-2db, and the box size is 50% larger.

Out of curiosity, what size room is this being used in? If it's a small room then you may be able to get away with tuning them even lower and still get respectable performance with some EQing. If it's a large room, then I would suggest larger drivers to begin with :)

Eric
 
My room I am looking at a theater room of roughly 225 square feet. I guess it is not that large. I could just buy a larger amp too I guess.

The surface area of these drivers when combined, is more than a normal 15" driver. I assumed that would be enough but I guess not.
 
Hi permo,

Here is a picture that might help:

PS: You can export the enclosure dimensions in HR by clicking on 'file' at the schematic diagram screen: Example in th picture.


I appreciate your efforts and your patience with me. I want to build this horn, but I need to get it right.

I noticed L12 was 158 cm. So that means that there are 158 centimeters between S1 (beginning of throat) and S2 (middle of driver(s)) correct? That puts the drivers a ways up the horn I think?

S4 would be the lenght of the opening at the end of the horn I think? What is S3 in this design?

if you don't have time to help or are frustrated with my slow learning curve, i sure understand.
 
225 sq ft isn't too aweful daunting. I think they are going to work fine as long as you aren't expecting listening levels that are nutty :)

Personally I would suggest building 2 separate boxes for them though, and setting them up as a sort of stereo pair of subs. You'll have more freedom to tweak the way they sound also. You may find that with proper room placement you can eek out some better bottom end from them.

I would personally build them ~1.5-2.5ft^3 per box. Tuning frequency anywhere in the 25-35hz range just depending on how much low end capability you want to strive for at the cost of efficiency. When you start trying to eek out the bottom end with over-sized boxes it seems like the quality of the bass reproduction can take a dump. (though, this varies depending on the box built quality and the driver dampening characteristics). If you can live without that 30hz and lower stuff, the smaller(ish) boxes tuned higher will probably result in lower distortion reproduction with faster transients.

I wouldn't worry about the amplifier power. The pair of speakers are rated to handle a combined ~500W RMS. The difference between 200W and 500W is roughly 4db. I wouldn't bother upgrading the amp UNLESS it's a lousy amplifier in terms of cleanliness and dampening characteristics. You want clean and well controlled power first and foremost. Quality>Quantity IMO.

Eric
 
225 sq ft isn't too aweful daunting. I think they are going to work fine as long as you aren't expecting listening levels that are nutty :)

Personally I would suggest building 2 separate boxes for them though, and setting them up as a sort of stereo pair of subs. You'll have more freedom to tweak the way they sound also. You may find that with proper room placement you can eek out some better bottom end from them.

I would personally build them ~1.5-2.5ft^3 per box. Tuning frequency anywhere in the 25-35hz range just depending on how much low end capability you want to strive for at the cost of efficiency. When you start trying to eek out the bottom end with over-sized boxes it seems like the quality of the bass reproduction can take a dump. (though, this varies depending on the box built quality and the driver dampening characteristics). If you can live without that 30hz and lower stuff, the smaller(ish) boxes tuned higher will probably result in lower distortion reproduction with faster transients.

I wouldn't worry about the amplifier power. The pair of speakers are rated to handle a combined ~500W RMS. The difference between 200W and 500W is roughly 4db. I wouldn't bother upgrading the amp UNLESS it's a lousy amplifier in terms of cleanliness and dampening characteristics. You want clean and well controlled power first and foremost. Quality>Quantity IMO.

Eric


Amplifier is Dayton Audio APA150, I think it is a pretty good amp.

I was also thinking 2.5-3.0 tuned to 28-30 hz ported. Likely a slot port but might break out the heat gun and mold some flared ports. We will see.

I would like to get the horn design to work out, but my brain can't quite wrap itself around the concept well enough yet.

I have modeled a 6th order BP just like you did, and I get a nice flat passband with good gain, but below about 35hz she shuts down. I want it to go to 25hz...or lower. Movies are my main objective.
 
Hi permo,

Looks like bjorno's design from Post #3 will work well.

There are a few small errors in the lower right hand corner of the picture: S1 (the opening close to the drivers) should be S4, and S4 (the close end of the duct inside the box) should be S1; in general, all the S's refer to the cross-sectional areas of the tube (or duct): S2 is on the side of the drivers (pick the middle between the two drivers) pointing towards the closed internal duct, and S3 is on the side of the drivers (again, in the middle between the drivers) pointing towards the mouth. S1 is the throat (close end in this case), and S4 is the mouth (opening close to the drivers). All the L's (e.g.: L12) refer to the distances between the S's.

I highly recommend you spend some time in Hornresp, there are a number of good tutorials on the web.

Regards,
 
Hi permo,

Looks like bjorno's design from Post #3 will work well.
I highly recommend you spend some time in Hornresp, there are a number of good tutorials on the web.

Regards,


I have spent the better part of the last month in horn response and have went through numerous tutorials. I think my problem is understanding the different types of horns and converting the numbers to an acutal box.

I can make a simple tapped horn fairly easily in hornresp, but I don't understand the difference between the designs and how hornresp is doing what it does.
 
Hi,

First: tb46

There are a few small errors in the lower right hand corner of the picture:

Quite correct: I seem to do this all the time,Thanks Oliver!

...but my brain can't quite wrap itself around the concept well enough yet...

If you are not in a hurry we can help you to sort out concept issues...

Submitting a picture revision of what Oliver have noticed here-above:

b :)


PS: The important distance here is L23 but L12 can be slightly off easily to correct with the necessary needed damping material. This can be shown in simulations, i.e. by using MJK:s or the AKAbak program.
 

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I have all the time in the world, I am doing this project as a side project related to a larger one. I am finishing my basement and this is a great chance to integrate the 7.1 system into the room.

I appreciate the help so much. Is there two openings or just the one by S1? How much space do I need between the internal baffles/dividers and the adjecent outer walls?

The lid is actually part of the enclosure wall, but removable to give driver access I assume?
 
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Movies you say, :) my specialty :p I like those two drivers in a 4ft^3 ported box tuned to 25Hz with a 3" x 10" slot port 27.6" long. pic below. This design would let you upgrade to a 500w amp and have reference spec.
 

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Still trying to put a cut sheet and dimensions together for the horn. I have some questions. I totally understand S1, S2, L12, L23..etc..etc.. here are my questions

1. Does each horn segment have to be a certain internal volume or am I more concerned about hitting my S and L variables appropriately?

2. How big/long do I make the opening?

I am starting to wonder if the lighbulb is ever going to get lit for me, regarding these horns!
 
I just started playing with hornresp myself tonight...

In one of the guides I was reading, S2 can be as small as 1/4 the Sd of the driver, but many drivers will work better with this dimension being larger. This is the "throat" or compression area so it's fairly important that this not be any larger than the Sd from my understanding (I could be wrong on this so someone feel free to chime in). It's also important not to go smaller than 1/4Sd as I guess that can cause problems.?

The same guide said that a good starting ballpark for S4 is driver Sd x 2 but this may change as you optimize the simulation.
 
After simming your driver in hornresp awhile, I'm convinced that this horn loading stuff is a lot more hype than anything. The best arrangement I could come up with produced similar efficiency and loading characteristics as the 6th order bandpass box I suggested above, however, the box would be nearly twice the size, and perform ~3db worse in maximum output compared to the 6th order bandpass configuration.
 
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