Purveyor; a dynamite small 3-way with concussive tendencies....

Now that InDIYana 2022 is post-op, I figured I post the details to this little marvel that impressed quite a few last weekend.
The name is appropriate, as Purveyor means to "provide what is required or necessary".

Goals:

  • Use a 0.23ft^3 knock down cab with a 3-way. This meant very careful driver selection, and a W-T/M orientation.
  • Make it easy to assemble for those with fewer tools. All but tweeters are surface mount.
  • Make it more affordable compared to most 3-way designs.
  • Yield great performance for the modest cost. All drivers have a magnetic shorting turn via a cap or ring.
  • Make a simplistic 3-way xover that is easy to assemble and would fit in the box with all of the drivers.
Drivers:

  • Peerless SLS 5" P830945; This is working in a 6 ltr net volume to produce F3/10 of 52/38. It also has higher sensitivity than ANY other 5.25" that can accomplish this bass extension feat. Being that, it has a lower Zmin above tuning at 150Hz of 2.3 ohms. This means the woofer lowpass coil has to be an air-core, and I was able to yield a Zmin of 2.6 ohms without speaker wires. This means it should be of a roughly stable 3 ohms by the amplifier sight, and a fairly stable 4 ohm load over all. It's a very minute area, and approaching 0 in terms of phase. Aluminum shorting ring, and long Xmax.
  • To accomplish this response in a small box such as this, there is no way you can use a port and tune low enough. It is just not possible. I was able to fit the SB Acoustics SB15SFCR-00 5x8" PR on the back of the cab. This involved using a midrange chamber of specific orientation to allow the PR to fit, albeit offset in one direction horizontally. 2x 0.5" x 1/8" thick washers and a stainless steel Allen-head M6x1 bolt were used to tune the PR to roughly 20Hz.
  • The Dayton Audio PC83-4 was used as the midrange. Being this is a 4 ohm driver, the xover landed at 650Hz to meld with the woofer to both keep impedance and xmax in check. Being the woofer is a 5.25", the off-axis response is really not impacted heavily. The tweeter and it landed at 5kHz, and the 83 has good enough off-axis response to make this just fine and keep the vocal range centered in the mid driver. The 83 also has a very benign breakup, likely due to its coated woven fiber cone, and it sounds fantastic. A decent xmax and copper cap keep it clean. 1 ltr sealed is all it needed, and this is a benefit here to give the woofer all the volume I could. (I used this midbass in the OSFA blue tooth speaker, and really liked its qualities. I also paired it with the following tweeter as a 2-way. I liked the results.)
  • The Dayton DSN25F-4 Designer Series 1" was chosen to finish off the top 2 octaves, 5k+. Paired with the PC83-4, the acoustic offset seems to be really similar, the CTC is small, and the frame is tiny. Sensitivity is 95dB, so it is heavily padded -13dB, and is loafing with a very easy living. On axis, there is a small rise at 12kHz of about 3dB, but most won't notice it. Just above the tweeter axis about 15* or +4", the rise disappears and the response is really smooth and flat. A copper cap keeps it clean. FF damps the Fs. Possible bonus? These tweeters have been known to be slightly leaky. If yes- then the midrange is in a slightly aperiodic box. If not- it does not impact the performance. Of note; I had a bad unit and PE replaced it. They are on back-order until July currently.
Place all into blender and pulse 3 times....

Xover points were 650/5k, not as pictured in the last sim-snap. I did not measure impedance and save it yet, so this should be close.
Xover board is 6" x 6.25". I ended up upgrading to the Cebo caps on the tweeters after the photo was taken. Much better, IMO.
Current prices:
P830945 = 36.98
PC83-4 = 12.98
DSN25F-4 = 18.98
SB15SFCR-00 = 35.70
Denovo 0.23ft^3 knock-down box = 26.98

Xovers as built: ~$115.20 each. I used the $4.00 75uF caps from ApexJr, and est a $1/resistor. The rest of the amounts are from Meniscus' website.

Total/cab comes to $247.14 including the cabinet, or $494.98; not bad for a compact 3-way! (My cost was $300 from discounts, salvaged upwound coils, used and free drivers, FWIW.) Most of the time, by the time you have xovers factored in with drivers on a 3-way, you're already in the $500+ category without even thinking about cabinets.
 

Attachments

  • IMG_4778.JPG
    IMG_4778.JPG
    579.6 KB · Views: 265
  • PurveryorSim2Final&VoicedXover.jpg
    PurveryorSim2Final&VoicedXover.jpg
    62 KB · Views: 231
  • PurveyorBox.jpg
    PurveyorBox.jpg
    207.3 KB · Views: 242
  • PurveyorCab.png
    PurveyorCab.png
    58.8 KB · Views: 211
  • Purveyor-RightHD+15degV_or4inches.jpg
    Purveyor-RightHD+15degV_or4inches.jpg
    134.2 KB · Views: 216
  • PurveyorSim2_AllMeasurements.jpg
    PurveyorSim2_AllMeasurements.jpg
    351.3 KB · Views: 178
  • PurveyorSim2_TweeterAxis_+15DegVRight_12thoctaveSmoothed.jpg
    PurveyorSim2_TweeterAxis_+15DegVRight_12thoctaveSmoothed.jpg
    67.8 KB · Views: 306
  • PurveyorSmallZoomFronts.jpg
    PurveyorSmallZoomFronts.jpg
    47.2 KB · Views: 319
  • SubtletySim1.jpg
    SubtletySim1.jpg
    246.8 KB · Views: 330
  • Like
  • Thank You
Reactions: 13 users
I am just in awe of your knowledge and experience. I have worked with Pete and John Hollander.
I actually finally got a project to the end with a crossover that I designed and built. I was very happy with it.
My current desktop speakers are pair of 16" cubes with 12 " B&E drivers I got from Erich. They are crossed at 2000 hz to a pair of BMS horn drivers and play to about 60 hz. The thing I have the most trouble with is going from measurements to data to go in Xsim. John helped me with this but my memory is not as good as it once was. I am building a set of speakers called Ares now with the 5.5 Anarchy woofer. Thank you for the reply. Sorry I missed DIY Indiana.
 
Maybe next year...

Like I said briefly in my acceptance speech, quoting Jeff, '"I didn't do this in a vacuum." either.' There were many people that have helped me along the way. I do this for the sheer enjoyment and love of music on a grand scale. I just have had a lot of practice. I have also pushed my boundaries and tested my skill level to see if I could actually do something I wanted to try. This includes both in xover circuits, and in wood working. If I don't try something new, I won't learn anything new. I also have an incredibly good sense for spatial awareness of objects used closely. I can usually see in my head how something will assemble or fit without drawing it, and drawing it gets it closer to scale for practicality.

Thank you for the compliment!
 
  • Like
Reactions: 1 user
Congratulations on the Lifetime Achievement Award!
Though hopefully you've got many more years of fun to come!

What I do know from the 2 decades of playing this game is that Ben has great ears, a great attitude and willingness to learn and teach.
I think all people who do great things have this tendency. These days there's a fancy term called "growth mindset" used by the developmental experts, and educators try to instil this habit into children. But some people have this natural curiosity and eagerness to learn and it just makes all the difference.
 
  • Like
Reactions: 1 user

billshurv

Member
Paid Member
2014-03-01 11:53 pm
I do like these threads about different ways of skinning the cat. A 3-way stuffed into 0.23cuft goes so against what is usually discussed on here it's made me really stop and think. Shame that over here we can't get knock down boxes so would have to learn the skills or pay someone for a custom build as that ticks the boxes for different. Most of the 3-ways I've seen discussed here have a bigger budget for just the midranges...
 
  • Like
Reactions: 1 user

burgunder

Member
2006-06-10 9:26 pm
I do like these threads about different ways of skinning the cat. A 3-way stuffed into 0.23cuft goes so against what is usually discussed on here it's made me really stop and think. Shame that over here we can't get knock down boxes so would have to learn the skills or pay someone for a custom build as that ticks the boxes for different. Most of the 3-ways I've seen discussed here have a bigger budget for just the midranges...
You can get them in Europe, if that's over here ;)