Tang Band W8-1772 Standmounts

Toppsy · Post by **Toppsy** » Wed Jun 30, 2010 2:24 pm

Finished veneering the top shelf of the stands this morning and added some felt disc pads for the speakers to cussion on then took some new photos in the outdoors sunshine. Just need to play a little with port lengths now to optimise the bass.

Dave the bass · Post by **Dave the bass** » Wed Jun 30, 2010 4:00 pm

Shoddy.....

DTB

andrew Ivimey · Post by **andrew Ivimey** » Wed Jun 30, 2010 4:34 pm

wouldn't give'em houseroom

Toppsy · Post by **Toppsy** » Wed Jun 30, 2010 6:12 pm

wouldn't give'em houseroom

That's why these are me new outdoor patio speakers

Toppsy · Post by **Toppsy** » Wed Jun 30, 2010 6:17 pm

The wife has just got home from work and has just seen the finished stands. "Those look nice" she says "you can make me a similar pair of small tables to go in the living room to stop you getting bore whilst waiting for the phone call for a real job".

Ya can't win

Mike H · Post by **Mike H** » Thu Jul 01, 2010 9:00 pm

LOL

chris661 · Post by **chris661** » Fri Jul 02, 2010 10:34 am

After running some numbers on winISD, I'm curious...

According to the tang band specs, the driver should require a 120 litre volume, tuned to 41Hz, to give a flat graph to 42Hz, a -3dB point of 38Hz and -10dB of 30Hz.

For a 40 litre box, a 3" vent at just under 6 inches gives the best graph (first picture).

With a little eq in the bass region (4dB gain at 55Hz, 1.5dB loss at 100Hz), you can get pretty flat (second picture). Cone excursion stays on the safe side, as it doesn't go higher than with a sealed cabinet.

In both cases, it's a 75mm dia. vent at 141mm long.

Chris

Edit - those pictures didn't show up too well...
Jpeg'd them instead, they look Ok when you open them, better than when they were in .gif...

Post by **Nick** » Fri Jul 02, 2010 10:56 am

Edit - those pictures didn't show up too well...
Jpeg'd them instead, they look Ok when you open them, better than when they were in .gif...

Yes, thats the point, what you see in the post is a thumbprint, the server takes the image, create a thumbprint of it, then make the small image a click able link to the full image. Otherwise we get huge images in line, which folk complained about.

chris661 · Post by **chris661** » Fri Jul 02, 2010 10:58 am

I meant when downloaded, they still looked awful.

jpeg looks a bit better, but there's still loss of colour information...

Scottmoose · Post by **Scottmoose** » Fri Jul 02, 2010 11:25 am

chris661 wrote:After running some numbers on winISD, I'm curious...

Probably because you appear to have accidentally used the 1808, not the 1772. Anyway, using Bob Brines's measured specs. on the 1772, 4th order alignment (lowest possible F3) is 46.34 litres, Fb 48.193Hz.

Remember however that WinISD doesn't account for room gain, so seemingly flat plots aren't necessarily 'best' in practice. On top of that, it has a number of other simplifying assumptions, and it does not consider internal standing waves, driver & vent location in the aforementioned box etc.

Toppsy · Post by **Toppsy** » Fri Jul 02, 2010 12:14 pm

For what's it's worth, these speakers were designed initially using UniBox NOT WinISD which has it's limitations as pointed out by Scott. Not that I'm saying unibox has any faults but seems a more useful tool to use than WinISD. They were then tweaked in Martin King's Mathcad worksheets to assess room gain.
In a BR design the optimum internal volume came out at 40L.

The Theile parameters to use for the W8-1772 are those as measured by Bob Brines NOT the published specs. http://www.diyaudio.com/forums/full-ran ... sions.html.

chris661 · Post by **chris661** » Fri Jul 02, 2010 2:33 pm

I agree that winISD has some limitations, but unless the cabinet is really big, standing waves won't be a problem for the operating frequencies of a subwoofer (which is all it's designed for). Still, it's usable to me as Open Office is more than a little clunky when running the Unibox spreadsheets.

Using the wrong driver was a bit stupid, I'll delete those pictures to save some space...

Scottmoose · Post by **Scottmoose** » Fri Jul 02, 2010 3:09 pm

...but unless the cabinet is really big, standing waves won't be a problem for the operating frequencies of a subwoofer...

You don't think so?

andrew Ivimey · Post by **andrew Ivimey** » Fri Jul 02, 2010 4:09 pm

If the cab is REALLY big, you won't get standing waves!

Post by **Nick** » Fri Jul 02, 2010 4:12 pm

Scottmoose wrote:
...but unless the cabinet is really big, standing waves won't be a problem for the operating frequencies of a subwoofer...
You don't think so?

What about harmonics?

audio-talk

Tang Band W8-1772 Standmounts

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