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

[Blenton]

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

JSR!! Glad to see you finally got that thing put together! Sorry to hear those cnc'd panels didn't line up to too well - too bad I couldn't take a whack at machining some for you. Though, if things go as planned, I'll have my own machine in the next little while I'm glad you like that JBL. It looks awesome! Like I said, I've used both the JBL and Infinity Reference 8 (the 860w) in both cars and home systems and I'm super impressed with them. I would agree with your assessment of box sizes and configurations - car audio guys like the bump around 40 hz, while I usually tune mine to at least 30hz (ported) so they get extension in to the 20's. Sealed, with cabin gain, extension in to the 30's was definitely there, but you can forget about the 20's. They just seem to run out of gas, even with a little boost on the bottom end :( But seriously, for an 8 it has phenomenal performance. If it were a 10, it would still have great performance.

@upsman - It would be interesting to see what the Reference 8 with a Yung SD-300-6 would sound like for more music oriented systems. The small enclosure is very appealing and with a little boost down low, extension *shouldn't* suffer too horribly. But we'll see. 2 would be nice, but, heck, why not 4?!? In ~1.2 ft^3, that's barely the size of my single 10" home theater sub. I've got three sitting in the basement; if only I had one more, then I could try it... maybe I'll have to yank the JBL out of the back of my exploder and try it...

[jsr]

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

Hey Blenton! Glad to hear from you. Let me know when you get your machine up and running. I always have builds I'd like to explore. Yeah, these little Harmon 8's do impress me. I have an Alpine R8 in my car now and I do think it's cleaner, but doesn't go as low as the Harmon brothers. I need a bit of boost around 30Hz, but can't find a cheap method to do that yet (my external EQ only goes down to 50Hz).

Go rip that JBL out of your truck and DO IT!

I watched a movie a couple of weeks ago (forgot the actual movie), but was able to turn the sub up a bit and could feel my seat shaking from the LFE and no signs of stress on the PR.

[Pete Basel]

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

Nice work, well thought out. It seemed too good to be true and looking over your sym I noticed that the true efficiency is a low 81.69 dB/W which makes sense for such a small box. The box will take a 12" and I have to wonder what the Infinity 1260 would do in that box sealed with say 6 dB of boost at 20 Hz. The PR and JBL driver are probably not too far off in price from the 1260. Curious just as a sanity check. I have simmed the 1260 but not recently and not in that small a box, I'll run one if I have some time. An LT would be ideal to fix any response problem with a 1260 but the 6 dB boost at 20 with the right stuffing might just work.
Again, nice design work, I like what you've come up with.

[jsr]

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

Thanks Pete. I tried to get the best extension in as small a cab as possible without any EQ. I don't have any electronics that would add boost down that low. Perhaps in the future, but for now, I wanted it to be simple and low cost...just choosing the right driver and box alignment combination, with a efficient low-cost amp. I believe some of the O-Audio plate amps have adjustable EQs, but they cost considerably more than the Yung I used.
Modeled in a slightly larger 1.3cf cab, with a PR that has more excursion, it can hit an F3 of 15Hz and still take a decent amount of power.
What's the lowest cost method to add boost in the 20-25Hz range?

[Pete Basel]

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

There is a version of the amp you used with 6 dB of boost at 30 Hz. It should be possible to lower the boost frequency by changing a few caps:

http://www.parts-express.com/pe/showdetl.cfm?partnumber=301-510

You might be able to do a passive shelving RC circuit if you have enough gain. Otherwise you just need an op amp.

[Blenton]

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

@ Pete -

I actually have the amp of which you speak - the Yung SD300-6 - and have been wondering if it is possible to shift the frequency and possibly the amplitude of the bass boost. Any idea how to go about doing that? One of my subs uses the Bash 300 and it comes with instructions for modifying the bass boost by swapping a few resistors. They even give you values and placement of the resisters. I haven't endeavored to modify it since I like it the way it is (it's wired up to a 12" sub tuned ~25hz; my neighbors would loath me if I turned up the boost

Anybody know if this can be done on the Yung amp? I can poke my way around a circuit board but am not an electronics expert. If anybody has ideas, I can post pics and am willing to pull out the soldering iron... I also have a 12" Infinity sub sitting in the basement to play with (and a 10" Reference, and a 10" Kappa that was going into the car but may pull HT duty). They all model very well in ported and sealed enclosures, but being able to boost the low end of one of those drivers in a sealed box lower than 30 hz would make me a happy camper. I like it when the walls start shaking. I've worked with them all before and like to tinker.

[Wolf]

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

Most of the time, the boost circuit is a standard Pi-filter, consisting of a couple resistors that can be swapped out; not caps.
Later,
Wolf

[Pete Basel]

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

Wolf, if the circuit is frequency dependent it needs a reactive component,
that being a capacitor in this case, in fact 2 capacitors when it is 2nd order.
There are also resistors setting the time constants but the caps are usually
easier to find.

[Pete Basel]

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

@ Pete -

I actually have the amp of which you speak - the Yung SD300-6 - and have been wondering if it is possible to shift the frequency and possibly the amplitude of the bass boost. Any idea how to go about doing that? One of my subs uses the Bash 300 and it comes with instructions for modifying the bass boost by swapping a few resistors. They even give you values and placement of the resisters. I haven't endeavored to modify it since I like it the way it is (it's wired up to a 12" sub tuned ~25hz; my neighbors would loath me if I turned up the boost

Anybody know if this can be done on the Yung amp? I can poke my way around a circuit board but am not an electronics expert. If anybody has ideas, I can post pics and am willing to pull out the soldering iron... I also have a 12" Infinity sub sitting in the basement to play with (and a 10" Reference, and a 10" Kappa that was going into the car but may pull HT duty). They all model very well in ported and sealed enclosures, but being able to boost the low end of one of those drivers in a sealed box lower than 30 hz would make me a happy camper. I like it when the walls start shaking. I've worked with them all before and like to tinker.

I've not done it on that amp so I suggest that you ask PE and perhaps start a new thread here asking if anyone has done it.
Look for an OP amp near the front end, and a pair of same value mylar caps near it, somewhere around .05 to .5 uF. That
is where you'd take a picure if you want us to try to help. A schematic and layout would make it easier of course - ask PE.

[Blenton]

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

I'll see what I can dig up. As I mentioned earlier, the boost for the Bash amps require a simple resistor change, just as Wolf mentioned. So perhaps that's where I will start with my examination.

Sorry to hi-jack your post, JSR... I'll start a new post

[jsr]

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

No prob Blenton.

I did see the SD300-6, but I need boost around 20-25Hz to give me the extension I wanted in a smaller design. It'd be great if someone can figure out how to adjust the boost frequency on the Yung amps. Per PE staff, the Yung amps also lack a HPF, just an FYI for anyone interested.

[johnnyrichards]

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

No prob Blenton.

I did see the SD300-6, but I need boost around 20-25Hz to give me the extension I wanted in a smaller design. It'd be great if someone can figure out how to adjust the boost frequency on the Yung amps. Per PE staff, the Yung amps also lack a HPF, just an FYI for anyone interested.

It would be interesting to see if that actually holds true, at least on the models with boost. AFIAK, no plate amps with boost do so with simple EQ - they almost always use a peaky high pass to accomplish that. The lack of a HPF on the un-boosted models is a possibility, of course - but rare.

[Pete Basel]

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

The "peaky" highpass is what's required to implement the T&S assisted alignments.
6 dB of boost is a HP with a Q of 2 and this combined with the correct box alignment
takes a 2nd order B2 closed box to 4th order Butterworth and a 4th order B4 box to a
6th order Butterworth. The exact alignment and response is not too critical as long
as the final response shape fits the requirements. The filtering of subsonic material
helps the system handle source with excessive subsonic material, noise such as LP
warp or sound effects that might damage the system.

[Benji]

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

Sorry to bring up an 'old' thread (4 days off being a year old! Happy Birthday Digger8!) but I wanted to see where things were nearly a year on and to ask a couple of questions.

So reading through Kevin's build thread on his Digger8 and some of JSR's comments it seems that the following is true:

Sub = JBL - Good, Infinity - Better
PR = Dayton - Good, AE PR12-970 - Better
Amp = Yung - Good, Bash - Better

Does this all still hold true or maybe there are some newer suggestions? Is the part number for the AE PR correct? Seems if all the 'better' options are ticked an F3 of slightly < 20 might be possible.

I was thinking about asking if takitaj on the forum would cut another box for me based on Kevin's specs but I just wanted to check if AE PR would physically be a straight drop in replacement for the Dayton PR?

Some places are reporting the Infinity REF860W as being out of stock, not sure if it's going EOL or it's just a stock shortage issue. Prices range from $52 (Amazon) to $80 (Infinity).

[aaronscalise]

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

Sub'd. Interested in doing this as well. Curious if Takitaj could still cut and ship one of these flat packs out. Also curious what it would cost.