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1x8 DIY practice cab build

#43
JdoubleH said:
If one's good, two's better, right? In theory, yes double the box + a little more for the internal displacement of the second driver, however I don't know if it would buy you anything really useful for electric bass. Where this shines is at low volume.

It looks like about 25 watts will drive this to xmax at 60hz.
Click to expand...

I was looking at the frequency response and pondering that it was probably pretty similar to an SVT 810 cab, and I got thinking that four boxes, each with a pair of speakers, might pair well with an SVT-CL. 8 times 70 watts (thermal limit) sounded about right to handle an SVT cranked up.

But that's why I asked about power at xmax. I guess my SVT would turn those drivers inside out.

I bet your design would pair nicely with my favorite coffeehouse amp: a 1950s-vintage Heathkit W5M (with matching preamp), which starts to saturate sweetly at about 25W.
 
#44
I don't "need" at all a new cab. But I have some plywood left from my two 1x15's, I also have paint, glue, tools. And the Fane soreveign 8-225 seems to be so good for this bargain price!
So if Santa's bringing me something from the music store next Christmas, I guess he'll add the 27€ driver with the corresponding grill. Nice ideas, thanks!
 
#45
To anybody looking to build a 1x8 practice cab, I would probably recommend a more substantial driver. I looked at the Eminence Alpha 8's and Fanes, but didn't find the response in my box quite to my liking, nor did I like the greater weight or cost. I also didn't want a ported box for this application.

The MCM driver I chose worked out very well for my application, but I had some VERY specific design criteria- among those were size, weight, and that it not be very loud or efficient. The quiet / low efficiency thing runs counter to most people's needs. I also wanted it to be as simple as possible, so sealed and one way, no tweeter or crossover, but with the smoothest response possible which reached acceptably low. For the upper range, it needed to extend beyond 4k if possible, since that is where so much of the electric bass character lives. In reality, the low end could roll off higher for my application, as the strong low register is a lot of what bleeds through walls (as I stated earlier, I build this for use at work during lunchtime in a conference room accompanying a couple of acoustic guitars). Also, the reality is most professional bass cabinets roll off higher than my f3 in the high 50's.

However I will say, having the depth my cabinet has with such a smooth response makes it a joy for low volume practice. I much prefer it to my Genz cabinets in that role. We'll see how I feel about that after I finish my next two cabinets, which will be a fEARful (12/6 or 15/6, haven't decided) and a BFM Jack12.

Final note about 1x8's - If you do decide to build one, keep your expectations modest. If you are looking to cover any kind of gig bigger than your bedroom, you'd be best to look to a bigger driver. I did once cover a college jazz big band rehearsal with a 2x8 cabinet not a whole lot bigger than this one powered by a GK200RCB. The band was pretty amazed how well it worked. But I only did it because the cabinet I had left at the rehearsal site found itself elsewhere that night ("borrowed" by someone who I can only remember by the unmentionable nickname he earned for it). It worked because of speaker placement and the stepped horn shaped room with a heavily damped large curved front wall.
 
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#46
rickdog said:
I was looking at the frequency response and pondering that it was probably pretty similar to an SVT 810 cab, and I got thinking that four boxes, each with a pair of speakers, might pair well with an SVT-CL. 8 times 70 watts (thermal limit) sounded about right to handle an SVT cranked up.

But that's why I asked about power at xmax. I guess my SVT would turn those drivers inside out.

I bet your design would pair nicely with my favorite coffeehouse amp: a 1950s-vintage Heathkit W5M (with matching preamp), which starts to saturate sweetly at about 25W.
Click to expand...

The SVT typically rolls off quite a bit higher than mine does, afaik around 100hz. I'm not sure my inefficient cab would be a good match for a small tube amp either, unless you are looking just for a practice amp, near field solo- actually the wattage rating is probably fine for this cab. But if you are looking for a good match for a coffeehouse setting, I'd recommend one of the BFM Jacks for high efficiency in a reasonably sized and reasonably lightweight cabinet. The Jack 10 can be built with a Beta10 for under $100, last I checked.
 
#47
First gig with 1x8!

Okay, so never mind that I said I wouldn't be gigging this cab, and that I didn't think it was suitable for even coffee house duty. Last night I had just such a gig- bass, acoustic guitar and un-mic'd vocals. The cab sounded fantastic in that low volume setting. With the eq set totally flat, I couldn't have asked for a better tone, and I couldn't ask for a simpler load in/out save for DI into house PA. I had the cab on the floor up against a wall for a little boundary reinforcement (actually that was unintended,we were just pushed up against a wall due to space constraints and my cab was simply at my feet). Much positive feedback.

Speaking of PA, we debated using the singer's, but thought it would be overkill. No telling how it would have done if I had to keep up with her mic'd. Perhaps it would be fine if she had a smaller PA (her's is your basic 2x way Peavey 15 neo plastic trapazoid and box amp/mixer) or full range acoustic guitar combo.

Actually, I think a small full range bass cab and a compact mixer into my aux-in might work really well, though something bigger than an 8 for sure- a 12/6, Thunderchild 12 or BFM Jack perhaps.
 
#49
That is a cool little speaker!

I've been toying with the idea of a tower 4x8". Something about 10" x 10" (WxD) and maybe 20" tall with a speaker on each face. Each speaker would be at a different height on its face to kind of spread out the way it couples with the floor. This way I can have a speaker pointing at me, my drummer can have a speaker pointing at him and the the other two will help even out the response in the room.

Anyways that speaker you used would be perfect for this. Do you have any desire to try to build this? I don't have access to a wood shop and if I did I might not come out with all of my fingers.
 
#50
Awesome Job, I wish there was more thought put into small battery-powered bass rigs.

I was introduced to 8" bass cabs thru my trusty Ampeg B2-48 combo. It's a ported design, and easily the bassiest cab I've ever owned.

I had a need for an ultra-portable amp. One that ran on batteries.

I bought one of the ampeg 8" drivers and dropped it into one of those cheep angled 8" cabs they sell for trucks at pep boys or something and powered it with a little Hitachi 18W amp I built and powered on a power tool battery. It would run for days on a 12V dewalt battery.

I used it alot for acoustic jams in San Francisco where my old bandmates' flat was about 100 steps up from the street level.

The bass response was never great. It sounded alot like the bass amps from the sixties. I always wanted to build a cab for this speaker that was 1/4 size of the original 4-8 speaker cab it was designed for.

The little amp I had was plenty loud for 2-acoustic guitars and vox, but I found that my active bass, over several months had a hot enough input signal to cook one of the electrolytics. I could make it overdrive pretty nicely, I'm sure that didn't help. Replaced that cap a few times with a bigger one of same value, and it lasted longer. Added a passive tone circuit to it to remove some of the string noise and warm it up a bit.

I'd really like to try this again using one of the EHX "amp pedals" as the speaker power. Not sure how the clean response is but you don't need alot of volume to keep up with two acoustics, just more than an acoustic bass can produce.

Monk
 
#52
Colonel Monk said:
Awesome Job, I wish there was more thought put into small battery-powered bass rigs.

...
Click to expand...
Monk,

The ehx pedal amps (22 Caliber and 44 Magnum) look interesting. My little cab is displacement limited to about 25 watts. The driver is rated at 70, so the power output of the pedals should work fine (assuming the ratings aren't total fiction).

But for battery power, my gut tells me you'd want greater efficiency, so probably bass reflex or something like a BFM Jack 10. This is a very quiet cab, even if it does sound really good.
 
#53
JdoubleH said:
Monk,

The ehx pedal amps (22 Caliber and 44 Magnum) look interesting. My little cab is displacement limited to about 25 watts. The driver is rated at 70, so the power output of the pedals should work fine (assuming the ratings aren't total fiction).

But for battery power, my gut tells me you'd want greater efficiency, so probably bass reflex or something like a BFM Jack 10. This is a very quiet cab, even if it does sound really good.
Click to expand...

Yeah the B2 CAB that the 4-8's were in is about 20 x 20 x 16 deep.

If I copied their design for one speak it would be 10 x 10 x 16 deep... That amp head put out about 200W RMS...

Agreed. I'm guessing there wouldn't be a way to get the Q value of the speakers, they are stamped St Louis Music on the back and as such an OEM driver.

I was just guessing that for low volume that putting the driver in a similar environment would yield similar results.

As for the power, there's really no doubt that 22W is enough power to amplify an electric bass to keep up with a few un-amplified acoustic guitars.

I didn't really care for my acoustic bass, since it wasn't loud enough for an unplugged jam what's the point right?

I'll get around to trying this and report back someday-ish.....

out
 
#54
JDoubleH,

Sorry for the thread revival. I am a design newbie although I've built two Jack10s. I was hunting for Duke's 10" design and found this one. I added this driver to WinISD and told it to spec a sealed box. It proposed a box with 66.9L volume, which is a lot larger than your box. If I give the box volume as 35L (15*11*13in), the response curve seems lower below 50Hz and slightly higher above that, which is an improvement for something this size, but the response through the midrange looks the same.

Do I have this right?
 
#55
Yes, the box doesn't affect mid response, just the lower end of things. Putting it in a smaller box will make it lose response in the low bass and put a hump in response in the midbass/highbass. If that hump gets too high the cab will sound too boomy, stuffing it with polyfill will help that some, assuming it's a sealed box.
 
#57
ian_s said:
Parts have arrived. I couldn't resist the allure of the $8 driver. If New Years weekend has time for wood shop time I might have it built soon!
Click to expand...

Cool! Sorry i missed your earlier post. Not sure about the answer to your question off the top of my head, but I'll look into it.

Edit: I originally modeled this in Bass Box Pro, so I'm not sure what you were seeing in WinISD. It should be similar (as it is based on the same calculations), but maybe double check your T/S entries (with specific attention to metric / imperial value input- very easy to transpose). Based on what I learned years ago from David Weems, I was aiming for a QTC of about .707 for optimally smooth response. The beauty of a sealed system is that it is very forgiving. There will be a distinct difference between boxes with lower or higher QTC, but the power handling and f3 will not be massively affected. They are also a bit more "tune-able" with damping. In short, less fail, more win, within the same relative ball park. I believe my final results are a bit higher than .707 for QTC (I added quite a bit of bracing and the handle recess took up a bit more space than I anticipated), but the results work great for me.

If I get a chance, I'll go back over my figures and perhaps throw it into WinISD for jollies.
 
#59
hover said:
Neat box. I guess I am most surprised that a consumer-grade bookshelf speaker woofer could even handle the transient spikes of actual instrument play without shredding...

very cool, and nice clean look.
Click to expand...
I've gotten the ptc to cut out exactly once, despite throwing quite a bit at it with the shuttle 6. It doesn't get anywhere close to loud, but for solo practice, it rocks. I use it frequently for rehearsal sessions with a singer and acoustic guitar. I've even done a coffee house session with it at a rather noisy Starbucks in the same format (bass, acoustic guitar, vocals).
I will say it is pretty obvious when you are pushing it too hard. It sounds great to a certain volume, then refuses to go any further cleanly. That its part if the beauty of a sealed box, really.
 
#60
I am certainly no WinISD fan... I thought I caught all the metric conversions but I think in the end I would have been happier with a set of equations and Matlab. I'm one of those kinds of geeks who doesn't believe point-and-drool tools very much.

Oh and to do a hill-climbing search among drivers given a box size.

I can't really see that the box needs too much bracing given the power of the driver and how low it should be pushed. Given that it's only 15" tall, one center brace about midway up would do it, assuming the Chinese birch ply I've got handy. No?
 

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