Low-cost DIY practice/coffeehouse tweeterless 110 [long]

[DukeLeJeune]

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Duke
Whats going on there, it looks like the speaker, horn are mounted to a door, is that a stereo cab?

Ha! I see what you mean!

It's a close-up of a stereo speaker, shot from an angle that conceals the sides. The front baffle is actually angled inward at 45 degrees. Here's the view from a bit further back in the room:

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I will confess that a bit of unsupervised interbreeding may have occured between my bass cabs and my home audio speakers.

 

[IntrepidCellist]

Those Prisms are dipoles though, right?

 

[DukeLeJeune]

Those Prisms are dipoles though, right?

Nope, they are monopoles, with bass-reflex cabinets. Two ports, one high and one low on the rear of the cabinet. Because of the generous boundary reinforcement we were getting in that hotel room (the pictures are from an audio show), I plugged the top port on one speaker and the bottom port on the other.

 

[IntrepidCellist]

Ahh, it must have been another of your speakers I was looking at that had the side woofer.

 

[DukeLeJeune]

Ahh, it must have been another of your speakers I was looking at that had the side woofer.

Yeah, I have some weird ones.

 

[DJ Bebop]

Ha! I see what you mean!

It's a close-up of a stereo speaker, shot from an angle that conceals the sides. The front baffle is actually angled inward at 45 degrees. Here's the view from a bit further back in the room:

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I will confess that a bit of unsupervised interbreeding may have occured between my bass cabs and my home audio speakers.

I bet all that monkey business sounds sweet

 

[greenboy]

Sorry Duke, only saw the shot you provided, and the angle definitely made it look like some of the dipoles I've seen.

Because the thermal rating on these is 150 watts (which means that the actual continuous is probably 50 watts, right), I thought I might try this and pair a couple of them with the MB200 or the Carvin Micro, which put out 200 watts. So I was wondering could I reduce the risk of blowing these by wiring them to run in series rather than parallel? Wouldn't this turn the rating from 4 ohms for a pair to 16 ohms, and reduce the wattage of these amps to 100 or so watts?

Why not just use the gain controls and ears effectively? This is no more mismatched in potential than a lot of bass rigs whose drivers fart way before their rating. Just back off some level or bass EQ if you hear over-excursion fartage. Parallel drivers is in general better anyway.

Actually when I had dual S2010 in my 210 cab I hooked it up to a lot of watts usually, because my rack always had my single-space 14-pound Peavey DPC14000X amp in it. 525 watts a side at 4 ohms. No problem, just pay attention. Even when guitars were using buzzkill distortion I was never so masked that I couldn't hear if I needed to roll off a little low end.

 

[1n3]

Duke mentioned that the tuning can be lowered without restricting the port too much:

Tuning frequency is 56 Hz stock, and net internal volume is about .90 cubic feet...
... If you want to try a tuning in between 48 Hz and 56 Hz, assume approximately 1 Hz change for each 1/2" of port width you eliminate. So if you run a 1/2" brace down the middle of the port, you're probably down to about 55 Hz. Lowering the tuning frequency reduces the output up at 80 Hz more than it reduces the output at 60 Hz, but both are reduced, in exchange for better fartout protection especially for low-B.

So far, no one has played with the port tuning on this box. 56hz may be a little high for some uses, particularly with a 5-string. For anyone who wants to try a lower tuning, I've got an experimental method to suggest:

Get some heavy corrugated cardboard. Cut a piece roughly 25-1/2" x 1-15/16", preferably with the corrugations running the short direction. 1-15/16" is the height of the port; you need a piece that will fit snugly from top to bottom. The port is 10-1/4" deep, so you need twice that length, plus the width of your port block. A 25-1/2" length gives you a center section 5" wide, which would drop the cabinet tuning about 10hz.

Bend the cardboard 90 degrees 10-1/4" from each end to make a U-shaped piece, and insert into the center of the port. To raise the tuning frequency, add a fold in the center, and narrow the insert to suit.

In case my description is unclear, here's a picture:

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Obviously, there are other ways to do this. This is a simple one that occurred to me. I haven't tried it, so if you do, let us know how it works.

 

[honestjohnny]

Sorry Duke, only saw the shot you provided, and the angle definitely made it look like some of the dipoles I've seen.



Why not just use the gain controls and ears effectively? This is no more mismatched in potential than a lot of bass rigs whose drivers fart way before their rating. Just back off some level or bass EQ if you hear over-excursion fartage. Parallel drivers is in general better anyway.

Actually when I had dual S2010 in my 210 cab I hooked it up to a lot of watts usually, because my rack always had my single-space 14-pound Peavey DPC14000X amp in it. 525 watts a side at 4 ohms. No problem, just pay attention. Even when guitars were using buzzkill distortion I was never so masked that I couldn't hear if I needed to roll off a little low end.

Yeah, I just like to fool proof things. And I'm usually the fool....

 

[DukeLeJeune]

Sorry Duke, only saw the shot you provided, and the angle definitely made it look like some of the dipoles I've seen.

No problem, it defintely looks like a dipole from that angle. Actually I've messed around with dipoles bit (augmenting them with four little subs on the bottom end), but don't have plans to produce any at this time.

Because the thermal rating on these is 150 watts (which means that the actual continuous is probably 50 watts, right)...

Sorry I overlooked your question yesterday. The spec sheet on the S2010 says 150 watts based on EIA 426A protocol, and 300 watts "music program". These are both thermal ratings. In practice the limiting factor is usually fartout, which in turn is a function of displacement (cone area x excursion), box size, box tuning, and the waveform the cab is asked to reproduce. One of the designs Eminence lists for the S2010 is a .90 cubic foot box tuned to 60 Hz, and they say the box is excursion-limited to 140 watts, but I don't know what assumptions they are making about the waveform (low B would be more demanding than low E, for example). Click here and scroll down to the "med. vented box"; I like the frequency response curve because there is no upper bass bumpage, which means you can EQ a bit without some notes becoming over-exagerated, and this is the only 10" I know of that will give you that nice of a curve in this size box. Since the box in this thread has a little bit lower tuning frequency (56 Hz), it might well have about 150 watts excursion-limited power handling based on whatever waveform Eminence assumed. In practice, the difference between 140 and 150 watts excursion-limited power handling is totally negligible, so it's really just bragging rights.

If someone does want some upper bass bumpage, just about any other Eminence 10" will deliver that in this box. And it's not a bad thing, just not my design goal. I like to minimize the loudness discrepancy between the first overtones as you go down the scale, so that the low notes don't "die" so much relative to the higher ones.

So far, no one has played with the port tuning on this box. 56hz may be a little high for some uses, particularly with a 5-string. For anyone who wants to try a lower tuning, I've got an experimental method to suggest...

I like your experiment and I like your drawings. For a permanent installation, you'd want the insert to be airtight and rigid, but the experiment would probably give you a useful indication of what to expect. In fact, you could probably glue 1/4" plywood to the cardboard to make it permanent, making sure to get a good glue seal along the seams.

 

[mikeddd]

Actually, I did get a break. In my woofer. Looks like I got a bad Basslite from PE. Last night I decided to crank it up a little bit. I'm a reasonable man; when I say "a little bit" I mean that. So far, I'd only played it at low-to-medium levels. Last night I turned it up so that you'd have to yell (not scream) for me to hear you.

That's when I heard it. A ticking noise coming from the speaker. NOT voicecoil slap. I know what that is; I was big into car stereo for many years and know what a bottoming-out sub sounds like. Ever hear a grain of rice or small, light thing vibrating on a surface? That's what this noise is and it's coming from right behind the dustcap. Ticking/buzzing noise. Got to be the voicecoil, or a stray piece of something that got in there during the manufacturing process.

At low volumes it's not there. But as soon as the cone starts to move back and forth a bit you hear it. The ticking/buzzing gets louder the more you crank it up. It's very noticeable. The driver is mounted correctly. It actually sounds really good (as I've said already) but when you turn it up, you get the good sound PLUS the ticking. I can't win.

I was thinking maybe it was a bad batch of Basslites, but MX21 has no issues with his. It's just my luck.

I already ordered another Basslite from Leland. On Monday I'll talk with a PE tech to see about getting an RMA#. Cust service wouldn't give me an RMA without a tech's approval. Ran out of time today to call; will call Monday.

So...who else is building one! C'mon people, this little guy rocks! Still needs a name...Duke's been oddly silent on this...

 

[greenboy]

Duke's been oddly silent on this...

Well, jeez, the guy designs actual complex speaker systems. Stuffing a stock woofer in a pre-built box is not exactly awe inspiring stuff to a guy who's got more components in a single crossover than everybody who's doing this project combined. Maybe he's brainstorming names for that crossover right now as I type ; }

Anyway, he did comment, and said it's up to the people here.


Sorry to hear woofer #1 broke, mike.

 

[mikeddd]

Yeah, you're right GB. I'm just happy as pie with this little box. It really does sound "that good" to my ears. I'm just pissed about the woof.

 

[1n3]

Ever hear a grain of rice or small, light thing vibrating on a surface? That's what this noise is and it's coming from right behind the dustcap. Ticking/buzzing noise. Got to be the voicecoil, or a stray piece of something that got in there during the manufacturing process.

Voice coil lead? Loose spider or spade terminal?

Still needs a name...Duke's been oddly silent on this...

Duke did suggest a name -

As for a name, up to you guys ...my nomination would be "TB110".

I also like MX21's suggestion - PE110. Neither will be sexy enough for some, I suppose. DuPE110?

I would say not Thunder-anything... that should be reserved for Duke's products.

 

[mikeddd]

I thought maybe it was a loose female terminal. Opened it up and sure enough one was loose. Tightened it up (it ain't moving now) put the woofer back and...that wasn't it. If the spider is loose or VC lead bad, there's nothing I can do about either of those. I've heard VC lead slap before. It's not that. I'm hoping that the tech from PE doesn't try to treat me like an idiot. "Is the speaker screwed in to the cabinet?" "Do you have any loose screws in the cabinet?" are questions that will get me fired up in a hurry. I just want to send it back for a refund or even store credit.

PE110 is accurate but totally non-sexy or cool. If that's what the community votes on though, I could live with it.

 

[greenboy]

Jeez, I hope Em still isn't having terminal leads that are a little too long or angled wrong. My very first neo driver from them was that way but I figured it out right away.

 

[mikeddd]

Jeez, I hope Em still isn't having terminal leads that are a little too long or angled wrong. My very first neo driver from them was that way but I figured it out right away.

What's the fix for that? Unsolder them from the terminals, cut shorter, resolder? How long are they supposed to be? Wouldn't that get caught in QA review?

 

[greenboy]

All I did was pull the wires firmly but not too hard into more of a shape that bent outward from the cone, if I recall, and put a little pinch/twist on them where they soldered into the terminal block. I wouldn't solder. Things can go very wrong unless you really have nessed with this stuff before.

 

[mikeddd]

Hmm. If I were to post a picture, could you tell me if the the VC leads are too long?

 

[1n3]

If the spider is loose or VC lead bad, there's nothing I can do about either of those. I've heard VC lead slap before. It's not that.

I have fixed loose spiders by slipping a palette knife (very thin) under the loosened area, with a little rubber or contact cement on it. Also have bent (gently) VC leads to get them out of the way of the cone. But you say it's not that.

Edit: didn't see Greenboy's similar comment