• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

AK Design Collaborative - Insignia-Class Economy Speakers (a.k.a Indignia)

dnewma04 said:
It's not from PE, but the SB Acoustics dome tweeter is reportedly excellent, as well.
Click to expand...

I don't know, Dave. It rolls off pretty steeply above about 24kHz. It might not work for running the mice out of the house. :D I like it.

Zilch said:
Woofers we've discussed thus far in BB6P suggested alignments, vented:
Click to expand...

:ntwrthy: Thanks Z! I was really dreading digging back through this thread to see what we'd looked at so far. I haven't been keeping a running log.

None beats DA175-8 for bass response and power handling.

Are we willing to take the 3 dB efficiency hit and work our way around crossing at 2 kHz?

Let's use it as benchmark for consideration of other drivers in 0.38 cuft. :yes:
Click to expand...

Good benchmark for bass but it kind of dies off above 1500Hz or so. We'd be roped into a low crossover for sure with that one.

Ray
 
RayW said:
Good benchmark for bass but it kind of dies off above 1500Hz or so. We'd be roped into a low crossover for sure with that one.
Click to expand...
In front, I'm not a tweeter guy, and thus don't have a lot of experience with different ones. There are several tweeters which claim to play down that low, but, consistent with Dave's experience, when you actually measure them, there are "issues." I was ultimately able to resolve them with the filters in AR4x and Presidian, but it'd be a damn sight easier if we could find a woofer as competent in the bass that played a bit higher.

Any suggestions for others to look at using 0.38 cuft.?
 
RayW said:
Looks like a sealed f3 of 93 with max SPL (1m) of about 102. F6 at 65 and F10 at 47Hz. It's a low Q design (.591) with a .25ft box.

Ported f3 of 61, f6 of 51, f10 of 42 with a 1.2dB hump at about 100Hz (it wants a bigger box).

Unfortunately, with the ported box it runs out of Xmax at 15W at about 80Hz.

Ray
Click to expand...

If you wanted to "cheat" a bit... as in, if you were just going to put together a box yourself, you could actually use TWO of the Dayton 5.25" 295-300 drivers and a Dayton 3/4" dome per cabinet in a D'Appolito arrangement, and probably STILL stay right at $100.

It'd take a cubic foot or so internal volume... but I've heard that combo (dual '300s and tweeter), and BOY, lemme tell you, it has DYNAMICS for a small speaker!

If I was going to try this,it would be interesting to build a floor-standing box out of say, 1x10 board lumber, with enough damping/bracing (automotive undercoating/1x2 braces) inside. Bet you could build it for REALLY cheap that way!!

Just did the math... with 1x10s, set up with the front and back baffles "on" the sides, you'd get about 7" x 8.5" inner width and depth... that, with a 3 foot tall cabinet, would be just over a cubic foot. You could build that out of one 12 foot 1x10 and 2 8 foot 1x10s, for a pair of cabinets...

I know this is counter to the original stated requirements of the project, buuuut... my mind works in its own ways... :D

Regards,
Gordon.
 
Zilch said:
In front, I'm not a tweeter guy, and thus don't have a lot of experience with different ones. There are several tweeters which claim to play down that low, but, consistent with Dave's experience, when you actually measure them, there are "issues." I was ultimately able to resolve them with the filters in AR4x and Presidian, but it'd be a damn sight easier if we could find a woofer as competent in the bass that played a bit higher.
Click to expand...

Yeah, the only "cheapie" tweeter I found that was "happy" playing down even as low as 1800 Hz, was the Dayton Classic 1.125" dome. And even then, it really needed a pretty steep slope (at least 12dB/oct with resonance impedance compensation) to work well...

For 1500 Hz... I dunno what you'd do...

Regards,
Gordon.
 
The SBAcoustics will play to 1500hz with a 2nd order crossover, but then parts cost might go up a bit dealing with that low of a point. However, I have seen people treat the cone of the 7" PE driver and add a phase plug and get good clean extension up in the 2500hz range. But then you need to remeasure T/S parameters...

Might be too agressive for this project. Can't we just make the budget 1,000USD and the size constraint 17 cu ft?
 
dnewma04 said:
I have seen people treat the cone of the 7" PE driver....
Click to expand...
"If it moves, Aquaplas it!"

attachment.php


[Sometimes if it doesn't move, as well.... :p: ]
 
dnewma04 said:
I

Back to some options, if we decide to make the jump to the .38 cu ft enclosure, the Dayton RS150S looks like a particularly good candidate. Tuned to 50hz, it would give us an F3 of 51hz. However, we would have an excursion limited power handling of 20-25w. Technically, it's approximately 20w, but I know these drivers can do a little more than their rated xmax without breaking too much of a sweat. If we bump the tuning freq up to 55hz, we get a 1dB peak around 75 hz, but we get a bit more power handling and possibly a little less port noise. I'd probably live with a little lower power handling and take the flatter response, but to most people, the little bit of midbass "bloom" might be welcome. And being ported, we can play with port lengths to tune to personal tastes.

The downside of course is that now we've knocked off 65.00 of our budget leaving 35.00 for a quality tweeter and crossover components. I suspect at this point, we are probably looking at electrolytics for all capacitors with a slight possibility of adding a film bypass cap for the high pass.

I have heard one speaker that used the HiVi SD1.1-A that sounded quite good and is 12.60ea leaving us with 10.00 for crossover parts. :(

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=297-416

Too many decisions... :)
Click to expand...

I was also looking at that driver. With a first-order lowpass and a strong notch filter at about 10K, you should be able to get a pretty nice 2.5KHz to 3KHz third-order rolloff. Yes, a notch filter takes a bit more components... but at 10KHz, it'd be tiny coils. You could probably roll your own coils, and the caps would be pretty cheap too.

Speaking of cheap caps, these are hard to beat.

http://www.madisound.com/catalog/index.php?manufacturers_id=139&sort=2a&filter_id=12

I've used virtually all of these, and they blow the doors off of any electrolytic. For this budget range, HIGHLY recommended, IMHO.

BTW: Those 3.3uf Madisound surplus caps? They're Panasonic polypropylene, 200v...

Regards,
Gordon.
 
Any of you guys know the movie "The Hudsucker Proxy"?

"Guys--- I got something. I GOT SOMETHING!!" :banana::banana::banana:

Try this plan:
Drivers:
Dayton RS150 woofer $28.29 each, $56.58/pair
HiFi TN25 tweeter $8.28 each, $16.56/pair

Crossovers:
(Tweeter)
2- 3.3uf Panasonic poly (surplus) $1.20/pair
2- .9mh Madisound 19g coils $8.70/pair (Madisound)
4- 15w resistors (values TBA, pad) $1.80/for 4 (Madisound)

(Woofer)
2- .45mh Madisound 20g coils $6.50/pair

(Woofer Notch filter- across woofer ~10KHz)
2- 2.2uf Madisound surplus mylar caps $0.60/pair
2- 3 ohm (or thereabout) 15w resistors $0.90/pair (Madisound)
2- .1mh 20g Madisound coils $4.80/pair

If my calculations are right, that's $97.64 for the whole shooting match. You could even add a Zobel to the woofer if needed, and STILL make it (PE electrolytic caps, say 6.8uf, and 15w Madisound resistors), coming in at just over $99.50!

Yeah, the tweeter is about 1.5 dB down at 20KHz, but I don't think that will make it sound bad. And crossed over at 2750 Hz second order, it should be fine... we can play with the values on it a bit, if needed...

So... whaddya all think? Huh? huh? huh? :D :D :D

Regards,
Gordon.
 
RS150 (Blk) vs. DA175 (Red):
 

Attachments

  • RS150 vs DA175 CA.jpg
    RS150 vs DA175 CA.jpg
    40.9 KB · Views: 105
  • RS150 vs DA175 EP.jpg
    RS150 vs DA175 EP.jpg
    39.9 KB · Views: 97
Oops... noticed that I was using the 4 ohm RS150. That's good, since the coil will be SMALLER... which will be CHEAPER. A .25mh coil is a significant less amount than a .45mh...

Longer Xmax too. That won't hurt!

Regards,
Gordon.
 
GordonW said:
Any of you guys know the movie "The Hudsucker Proxy"?
Click to expand...

Was that the one about the hula hoop?

Looks like a good design to me, G. I'm currently listening to a design-in-progress using the RS180 and it sounds really good. I would expect it's little brother to sound as good through the midrange. I'll be leaving pretty soon for the weekend. I'll have to play around with numbers when I get back.

Z, the bass looks like a big difference but they don't really diverge until below 40Hz which is lower than we'll be able to hear anyway. I'm just concerned about the breakup on the DA175. The RS holds it off until way up high. We could try aquaplas on the aluminum cone and see if that tames it. Granted, I've never heard it so I may just be crying wolf over nothing.

Ray
 
RayW said:
Z, the bass looks like a big difference but they don't really diverge until below 40Hz which is lower than we'll be able to hear anyway.
Click to expand...
Problem is, RS150 won't even make it to that 40 Hz. From the EP curves, it's outta gas at 50 Hz. DA175 works it 10 Hz lower.

RayW said:
I'm just concerned about the breakup on the DA175. The RS holds it off until way up high.
Click to expand...
I believe we can bury the breakup with a third-order highpass filter, if necessary. The real problem in my view is the notch between 1.5 and 2 kHz, if it's real, and finding a tweeter that will play nice down there.

http://www.zaphaudio.com/BAMTM.html

With the SB Acoustics tweeter, we're close, with $16.70 left for crossover parts, and more, if we can negotiate group buys or AK member pricing. I'll have these under test next week.

DA175 is multii-modal in 0.38 cuft. -- vented, it's nearfield, freefield, or West Coast bass (with boundary reinforcement). Plug the port for East Coast.... :thmbsp:
 
If you look at PEs response graphs, they nearly all take a nasty dip in that region, my guess would be that it's an artifact from the baffle used during measuring. :)

As far as bass extension goes, i'm happy with an F6 in the 60-70hz range, frankly. Anything else is just icing on the cake.
 
You must log in or register to reply here.
Back
Top Bottom