Digger8 Sub - diggity dig it all the way to 20Hz

[TKanzler]

Re: Digger8 Sub - diggity dig it all the way to 20Hz

I have another revision that is smaller than the current design while providing the same performance. I just don't have time to confirm fitment. The smaller (more space efficient) design costs more than the original Digger8 but costs are the same as the improved versions that many are making. Perhaps some generous person with time and money for some mdf and cutting can help me confirm fitment to get this smaller version out.

I haven't been able to find the new and improved version anywhere. Did you post any details somewhere?

I'd like to give it a go, either the original, or the improved version. Space (well, WAF actually) is tight, so small is good, and more than one may be better, and shouldn't pluck the wrong nerve. :rolleyes:

[jsr]

Re: Digger8 Sub - diggity dig it all the way to 20Hz

I only have the sim. If anyone has measured it, please post. Thanks.

[Pete Basel]

Re: Digger8 Sub - diggity dig it all the way to 20Hz

Has anyone measured the input impedance to the woofer on a
completed closed up system?

[jsr]

Re: Digger8 Sub - diggity dig it all the way to 20Hz

1.5in is fine. I'd like a bit of margin so I'd see if I could find 2-2.5in personally but 1.5in will work fine.

[bluejay29560]

Re: Digger8 Sub - diggity dig it all the way to 20Hz

Thanks again JSR. I know that the down-firing active driver design is not yours, but do you think that 1.5" rubber feet will give enough height to allow the Infinity to "breathe" properly? I looked at the Outlaw 8" ported down-firing sub and it appears to use 1.5" rubber feet. Merci....Bluejay

[jsr]

Re: Digger8 Sub - diggity dig it all the way to 20Hz

No need for any insulation or lining. The cone mass of the active and especially passive drivers are so heavy that any higher frequency energy in the cab is too small energy to move them and the frequencies the sub works at have wavelengths much longer than any internal dimension of the cab.

[bluejay29560]

Re: Digger8 Sub - diggity dig it all the way to 20Hz

Mister JSR, I decided to get the 1cu ft Denovo box from DIY and modify it into a 12" front firing Dayton 12" PR with 30 2"x.5" washers and a down firing 8" Infinity active sub. I will have to remove some of the internal bracing to accept the Infinity, but plan to glue the removed piece into the cabinet in some way to keep the volume correct. My question is do I need to add any insulation and if so, what do you recommend? Thank you sir in advance...Bluejay

[Chris Roemer]

Re: Digger8 Sub - diggity dig it all the way to 20Hz

Much easier is to just crawl around yourself, with your sub at your listening position. When you get your head to a spot that sounds good (and where you'll be allowed to actually PUT a sub), just swap your head for the sub. The end result will be the same.

[Telperion]

Re: Digger8 Sub - diggity dig it all the way to 20Hz

I currently have a Polk PSW10, so virtually anything is a big improvement over that. Plus with the shape of my living room, I have no space for a 14-16" square sub, so I'm looking at either building one of these, or having no sub at all. Unfortunate dilemma.

I attached a diagram of my living room, the red blocks are about the only 2 locations I can place a sub. I have 10-12" of clearance behind the TV console. The other option beside the couch is probably the better location, but would mean running a subwoofer cable through my attic and installing 2 wall plates.

(Click for full-size)

[bluejay29560]

Re: Digger8 Sub - diggity dig it all the way to 20Hz

Thanks man!

[jsr]

Re: Digger8 Sub - diggity dig it all the way to 20Hz

Hi blue,
As long as the screw has sufficient torque you don't need to glue the washers together. I would however advise in applying loctite to the screw. Since the assembly is under constant distress when in use, loctite will ensure a lasting connection. I use blue so that I can remove it should the requirement arise. Blue is strong enough but not permanent.
Have fun.

[bluejay29560]

Re: Digger8 Sub - diggity dig it all the way to 20Hz

Good Saturday evening JSR. I have finished the weight add for the Dayton PR. 30 2" fender washers(1/2" id) length 1.75" with a 2" screw to replace the >75" screw that came with the unit. I added some 1/2" rubber tubing inside of the stack with an inside diameter of the screw to make the assembly more stable. Do I need to try to encapsulate or bond in any way all these washers and do I need to loctite the screw? I'd hate for all this to come apart during an intense LFE moment. As always thanks in advance for your sage advice....Bluejay

[jsr]

Re: Digger8 Sub - diggity dig it all the way to 20Hz

So I hate auto correction on my phone.

Regarding placement that kevin spoke of, a sub goal of the Digger8 was that since one is so affordable, you can get several for less than what other subs cost for one and get much more even room coverage. If you really want optimal coverage, you'll need to do what's referred to as a sub crawl. .. crawl the sub little by little around the room for best performance at you're listeninglocation. This difficulty magnifies considerably though with more subs.
I can design a compact sub with even better performance with built in EQ and room correction but that's so costly toy can just buy a servo sub for the price.

[jsr]

Re: Digger8 Sub - diggity dig it all the way to 20Hz

I think most questions are answered within the thread. The dimensions of the cab are in my first post which if I recall right is 9x14x20in.
There's no restrictions on the shape of the weights as long as they don't interfere with anything else sick as clearances to the brace or active driver. I didn't dictate the brace design as really it doesn't matter as long as its there Anna sufficient. My brace has adequate clearance for the PR as I purposely notched out a section to clear the weights. Just ensure that is taken into consideration in your layout.
The original goal of the Digger8 was very low frequency at minimal cost. That meant drivers, both passive and active, of minimal cost and amps. Amps with EQ typically cost more, sometimes several fold more, so the design incorporates no needed boost. It's pure matching and tuning of drivers and cabinet.
There are definitely ways to improve the design in various ways but all add cost. I guess my design has outgrown its original goals now and I should post some updates for performance revisions.
The power handling and frequency extension differences between the JBL and Infinity drivers is minimal. You won't hear the difference. You should choose that based on aesthetic preference. The PR Dora make a difference though and the AE is a much better performer at a bit over double the price. Still it's a good value in performance for the money compared to other much more expensive PRs. AEs PRs are mdf based and solid. I think their design helps provide the performance at reduced cost compared to other brands. But they are slow as I stated in the first post.
I have another revision that is smaller than the current design while providing the same performance. I just don't have time to confirm fitment. The smaller (more space efficient) design costs more than the original Digger8 but costs are the same as the improved versions that many are making. Perhaps some generous person with time and money for some mdf and cutting can help me confirm fitment to get this smaller version out.
Hopefully I addressed all questions. Feel free to re-ask if I didn't as my brain hurts now from work.

[kevin007]

Re: Digger8 Sub - diggity dig it all the way to 20Hz

Does anyone have the exact dimensions needed for the cabinet, bracing, etc? I have no experience in DIY
audio but this project intrigues me due to limitations in my living room on where I can fit a subwoofer.

How much clearance does there need to be between the PR and a wall or entertainment console?

Subwoofers are all about placement. Room modes interfere with bass response and differ from room to room. What many people do is use multiple subs to overcome this problem. Many times using 4 or more.

I plan on using at least two up front and one rear for my new HT build. Some times you just have to experiment.

Kevin