New project - J1 - Budget three way

[brianpowers27]

Project: J1 Budget3way

Summary: A nice mid-low budget three way capable of playing cleanly around 100db. The xo is a 2nd order @300 mid-woofer and 3rd order bw @3500hz mid-tweet. The mid and tweeter drivers were chosen for their high dispersion characteristics and the woofer was selected for the quality of the clean bass it produces.



full BSC

Drivers.

• Dayton RS225s-8 8" woofer
• Tangband w3-1053sc
• Dayton nd20fb 3/4" tweeter

Box specs:
wall thick'
0.75
inner outer
x 40.5 42
y 8 9.5
z 10.5 12
gross 3402 in2
misc 200 xo, bracing, drivers
net 3202
Ft 3 1.853
liters 52


Port
2" diameter
7.5" 23hz tuning

Note: mid chamber should be configured for 3 l. This is approximately 8.5,4,6
Bracing: Minimum 2 window pane braces. one just below the woofer, one directly above it.

Driver centers
tweet 37.6875
mid 33.34375
woofer 26.375


XO

• Active -- tested target slopes of lr2@ 450hz woof-mid 3500hz bw3 mid-tweet
• Passive coming soon based on targets in active simulation.

Impressions
[list][*]Excellently clean for the money[*]Plays loud[*]Small enough tower to earn WAF[*]Dispersion is wide... could be good or bad depending on your philosophy[*]Resolves the intricate de3tails of John Williams' Star Wars theme and is meaty enough to belt out Nightwish.

[Ludo]

Brian,

Interesting combination of drivers.

Did you consider using the Dayton Classic 8 inch instead of the RS?
That would cut $30 per side off the cost.

Louis

[Pete Schumacher ®]

Project: J1 Budget3way

Summary: A nice mid-low budget three way capable of playing cleanly around 100db. The xo is a 2nd order @300 mid-woofer and 3rd order bw @3500hz mid-tweet. The mid and tweeter drivers were chosen for their high dispersion characteristics and the woofer was selected for the quality of the clean bass it produces.



full BSC

Drivers.

• Dayton RS225s-8 8" woofer
• Tangband w3-1053sc
• Dayton nd20fb 3/4" tweeter

Box specs:
wall thick'
0.75
inner outer
x 40.5 42
y 8 9.5
z 10.5 12
gross 3402 in2
misc 200 xo, bracing, drivers
net 3202
Ft 3 1.853
liters 52


Port
2" diameter
7.5" 23hz tuning

Note: mid chamber should be configured for 3 l. This is approximately 8.5,4,6
Bracing: Minimum 2 window pane braces. one just below the woofer, one directly above it.

Driver centers
tweet 37.6875
mid 33.34375
woofer 26.375


XO

• Active -- tested target slopes of lr2@ 450hz woof-mid 3500hz bw3 mid-tweet
• Passive coming soon based on targets in active simulation.

Impressions
[list][*]Excellently clean for the money[*]Plays loud[*]Small enough tower to earn WAF[*]Dispersion is wide... could be good or bad depending on your philosophy[*]Resolves the intricate de3tails of John Williams' Star Wars theme and is meaty enough to belt out Nightwish.

What's happening there at 200Hz? Room mode? Floor reflection? Internal standing wave?

[mzisserson]

I like the look of the endgrain. I wish some of you lived closer so I cold hear your stuff!!!!

[Wolf]

What's happening there at 200Hz? Room mode? Floor reflection? Internal standing wave?

That very well could be a standing wave in addition to reflection in measurements.

The reason I think it could be a standing wave, is that it reoccurs slightly at 400 Hz. That would be the octave...

I know Brian to do well at lining his cabs, but maybe a little more in the bottom would make a difference?
Later,
Wolf

[critofur]

Brian, would you be willing to put one speaker on it's side and measure?

Would be good to separate standing waves from floor bounce nulls...

[brianpowers27]

Here is a ground place measurement taken at 1m.

[Pete Schumacher ®]

Brian, are you planning on adding a bit of boost and a higher roll off for the tweeter to get that top octave more in line?

[brianpowers27]

Brian, are you planning on adding a bit of boost and a higher roll off for the tweeter to get that top octave more in line?

Nope. It sounds pretty good to me. I am a tiny bit surprised that those tweeters rolled off like they did considering. THe xo is not boosting the tweeter in that range and the nd20 is naturally strong in that range. The .75" dome sounds well balanced to my ears when crossed above 3500hz. I can't say for certain but the sim above is likely not indicative of the true top octave response.

For anyone interested, you are certainly welcome to play around with the source files.

Sorry for the lack of in depth coverage. I have too much on the plate currently... This is a wedding present for a friend who is getting married in two weeks.

[critofur]

Here is a ground place measurement taken at 1m.

Thanks for posting that Brian.

Wolf you see that? Looks like the dip is more of a floor bounce null - the only dips near that FR range are much shallower and at diff. frequencies in the G.P. measurement as compared to the previous sim FR posted.

Speakers that I have liked in listening tests generally have a design that mitigates the floor bounce cancellation null.

[Pete Schumacher ®]

Nope. It sounds pretty good to me. I am a tiny bit surprised that those tweeters rolled off like they did considering. THe xo is not boosting the tweeter in that range and the nd20 is naturally strong in that range. The .75" dome sounds well balanced to my ears when crossed above 3500hz. I can't say for certain but the sim above is likely not indicative of the true top octave response.

For anyone interested, you are certainly welcome to play around with the source files.

Sorry for the lack of in depth coverage. I have too much on the plate currently... This is a wedding present for a friend who is getting married in two weeks.

Your measurements agree with Zaph. Definite droop to the output as frequency moves up. That's what I was hinting at. By boosting the level while simultaneously increasing the HP cutoff frequency, you'd reverse that trend and still get that seamless blend to the TB. Also consider that the droop will be even more pronounced as you move off axis.

I'd be happy to have a gander at the files . . .

[brianpowers27]

Your measurements agree with Zaph. Definite droop to the output as frequency moves up. That's what I was hinting at. By boosting the level while simultaneously increasing the HP cutoff frequency, you'd reverse that trend and still get that seamless blend to the TB. Also consider that the droop will be even more pronounced as you move off axis.

I'd be happy to have a gander at the files . . .

I could be wrong but I don't really see the droop in the graph posted until around 30khz.

P.S. The measurements were likely taken at 48khz if that means anything.

[critofur]

Your measurements agree with Zaph. Definite droop to the output as frequency moves up. That's what I was hinting at. By boosting the level while simultaneously increasing the HP cutoff frequency, you'd reverse that trend and still get that seamless blend to the TB. Also consider that the droop will be even more pronounced as you move off axis.

I'd be happy to have a gander at the files . . .

http://www.zaphaudio.com/tweetermish...D16FA-6-FR.gif

Pete, you posted the FR graph of the ND16, not the ND20FB that Brian used, which can be seen here:

[Pete Schumacher ®]

Pete, you posted the FR graph of the ND16, not the ND20FB that Brian used, which can be seen here:

My mistake. I thought it was the ND16 up there on top. Didn't read closely enough.

Point still holds. Either there's a calibration error with the mic, or there's going to be zilch off axis high end. The blending to the mid is excellent by the plots posted, but I would do something to bring up the top octave, if there's no calibration error.