Zaph's Bargain Mini MCM woofer back in stock

[technimac]

Just noticed over on the MCM site that the MCM 55-1853 woofer is back in stock. Good news for anyone who was holding off on this project due to this item being out-of-stock. :W
Zaph notes that the 35mm Forstner bit needed to install the Aura is used to mount clocks, but it is also the standard bit for installing (Blum) "Euro-hinges" and is widely available for that purpose. :T
~Bruce

[jkrutke]

Thanks for the heads-up on that. I know there's a lot of people waiting for that woofer to be back in stock again. Now we'll see how long it takes to sell out again.

[happy]

Thanks for the heads up... I just ordered a pair and am excited as I have been waiting to build a pair of these for my kitchen

[JonP]

Good to know... Wish I'd back ordered some more while they were on sale... but I just ordered the last 4 they had. One showed up with shipping damage, now I can get that taken care of...

[technimac]

I was talking to my neighbour today and he is very interested in building a pair of these for his open-plan living room.
They would be for music only and wall-mounted between windows (prewired for this and there's a view, so no curtains allowed by SWMBO), and the enclosures would have to be "elongated" to fit the space. So, they would also be tapered, with the top being, say 6" deep and the bottom, 2". Front vented near the top and using Zaph's "non-BSC version" of the X-over.
So far I see no problem.
Now, for a sub to handle the bottom end. We're considering the Dayton RS315HF-4 12" in a vented 2.5ft/3 enclosure powered with the Bash 300 (current DOTD) . Probably cross at ~100Hz or so.
Any big concerns with this combo (save for the unavoidable issue of these being "wall-mounted")?
TIA
~Bruce

[Jonny_boy]

Would a RS-225 be a cheaper but viable solution for a small sub? Since it will be for music and not movies, it might not need to be a 12" sub?

[technimac]

Would a RS-225 be a cheaper but viable solution for a small sub? Since it will be for music and not movies, it might not need to be a 12" sub?

Thanks for the suggestion, but....unfortunately, the RS225 isn't a subwoofer and the room is large.
So either the RSS265HF-4 or the RS315HF-4, mentioned above, are the most likely candidates. Sealed is another option, seeing as this will be for music only.

[JonP]

Now, for a sub to handle the bottom end. We're considering the Dayton RS315HF-4 12" in a vented 2.5ft/3 enclosure powered with the Bash 300 (current DOTD) . Probably cross at ~100Hz or so.
Any big concerns with this combo (save for the unavoidable issue of these being "wall-mounted")?
TIA
~Bruce

I've been fooling around with a 315HF sub and 300W BASH for a friend... got it in a 3cu ft box and was aiming at a ported design. Problem is, you gotta put a LOT of port in the box. I was leery of using a 3" port due to noise, and went with 4". Well, long story short, I ended up squeezeing 25" of port into a 17" ID box. 4 elbows with short connectors later... It sounded pretty mushy. :M The pipe resonance was down near 200Hz... I could hear port noise on low sweeps, probably due to all those right angles and edges in the plumbing... My Quatro 15" in a sealed 2.6 cu ft box sounded more musical... Sigh...

Yeah, it had >6dB more output below 30Hz, about 10Hz lower extension, and it was most impressive (wife REALLY freaked out this time with the test tones), but...
A cautionary tale of going too far to get where you wanted to go... I actually am converting it back to sealed.

Sealed, it sounds very nice, clean and tight. And, I don't even have stuffing in it yet. (need to add more bracing to that box first). Since your friend isn't as interested in movie requirements, going with a sealed should be great.

Our family room extends to the kitchen, so it's pretty roomy and open plan as well.

[technimac]

I've been fooling around with a 315HF sub and 300W BASH for a friend... got it in a 3cu ft box and was aiming at a ported design. Problem is, you gotta put a LOT of port in the box....It sounded pretty mushy. 8O

Sealed, it sounds very nice, clean and tight. And, I don't even have stuffing in it yet. (need to add more bracing to that box first). Since your friend isn't as interested in movie requirements, going with a sealed should be great.

Jon, That's exactly what I needed to hear. We just measured up the space, and at ~ 2ft/3, a sealed 315HF will be perfect for it. :T

Thanks,
~Bruce

[Jonny_boy]

What is the difference between HF and HO models?

[Brian Bunge]

The HF has lower Le and requires a larger box for any given sealed or ported alignment. The HO has greater power handling, greater Le, and works in smaller enclosures.

[Hank]

Brian boy, what's shakin' in Florida? Hope you had a great Thanksgiving! My son is here this weekend from NYC, but for the past several hours has been on line working :-( On call, you know. All the best to you!!

[Brian Bunge]

Hank ol' man, not much down here! Keep wishing we'd get a weekend with highs consistently in the 60's to make speaker building more appealing. But upper 70's to low 80's still make we want to stay indoors unless I have motivation (ie money) to get me out there sweating.

I'm selling my big towers if you want to make a road trip out here to pick them up! Could make a great Christmas present for one of your kids!

[Jonny_boy]

The HF has lower Le and requires a larger box for any given sealed or ported alignment. The HO has greater power handling, greater Le, and works in smaller enclosures.

What would that mean in terms of sound quality?

[Brian Bunge]

The lower Le of the HF series drivers allow them to be crossed higher up (200Hz or so I believe) so that they can also be used more like a traditional woofer will still being able to extend down into the typical subwoofer range.

Also, it should be noted that I have recently heard of several people on the PE forum hearing some sort of noise (motor noise prehaps) from the HF series subs. I know in at least one instance switching to the HO series driver alleviated the problem. I've used the HO series drivers in several subs and have had nothing but great success with them. I've never used the HF's.

[JonP]

It's kind of buried deep in one of the threads, but the original guy with the 15" HF's suddenly determined he had air leaks around screws, thru his box joints and under the countersink. So, his problem wasn't cone noise.

At least one other guy had a similar complaint with the 10", that might have been cone related. But, you'd think the smaller cones would be stiffer, and you'd be more likely to have flexing with the larger ones. I can say that my 12" HF I mentioned earlier has no noise driven hard with sweep tones down to 10Hz...

[Jonny_boy]

Could Zaph's design be adapted to a MTM using the same drivers? Would the 3000hz x-over need to change?

The point is to make small 4 Ohm speakers for a mini stereo I have that is actually quite nice but needs new speakers. Also suing 2 mid-woofers would help in avoiding a sub and all the added complexity involved. As a bonus, it might get better sensitivity.

[mtnickel]

Good to see they have more stock. I must've cleaned em out when i ordered my 5.

Upon cutting all the boxes...i was pleasantly surprized to see how "MINI" these things actually are. Looking forward to hearing them.

Oh, and for the Tweeter cutout hole.
I had to be creative with this as i couldn't find anything locally, and didn't order the bit with the rest of my parts...

My solution: Look through all your router bits and find one with a total outer diameter of 35-36mm. Sure enough, one of my roundover bits was VERY close. Just a matter of drilling a decent size hole first to fit the bearing, then clamp down the router to the baffle, and slowly plunge out the hole.
Hopefully this helps someone!

Mark

[jkrutke]

Could Zaph's design be adapted to a MTM using the same drivers? Would the 3000hz x-over need to change?

This was a subject of another discussion over at PE but I couldn't find the thread. Someone took a stab at new crossover values, I modeled with existing TM data, suggested changes, discussed some other issues and described how this method of designing an MTM falls short.

Then I realized: The thread had been deleted. The PE folks hate all things MCM and will not allow discussion of their products there. That angers me a bit. It's rare that I actually offer to help someone, so I hate to see it deleted when I do. I don't feel like repeating that whole discussion again. Maybe you can find the guy at the PE forum who was building the MTMs before your thread gets deleted.

My solution: Look through all your router bits and find one with a total outer diameter of 35-36mm. Sure enough, one of my roundover bits was VERY close.

Great idea, I'll have to check out some of my router bits. I can visualize what size they are and I know I have some that have to be close...

[EdL]

This past weekend @ diy Lexington, Dr. Jim Griffin displayed a speaker with a novel enclosure. He used a composite fence post sleeve. His design was a MLQW.
I've begun looking for these locally. I know I can get square pvc tubes up to 5" square x 42" or longer. Now, the square x-section may warrant some internal baffles or damping. This just seems like an elegant means to an end.

[EdL]

Using the search function on the PE forum I found some references to conversion to an mtm. A proposal by Chris received a response from Zaph:

quote:
"This is what I'd do if I wanted to do what you want to do.
*HP: same XO but change 4 ohm to 2.4 ohm resistor and delete the 5 ohm to ground. You will be raising the little guy's output by 6dB at its Fs, but it may still be OK.
*LP: use a #18 0.75 coil in series, and a 6.8uF shunt cap for your parallelled MCM woofers. This WILL change this to a 4 ohm nominal system, but it should be roughly 6dB more efficient.
For a cab I'd shoot for 0.35 cf keeping the baffle width the same 6-1/4". I'd run your woofs as close as practical with the tweeter in between but all in line down the center of the cab, just like the TM. I'd run a 1.5" id port that's 3.0" long right out the back, as far from the woofs as possible. If you make your cabs taller (and not so deep), keep the drivers high and run the port out the back about 3" from the bottom.
Have fun. Chris

Zaph replied:
That all works, but instead of deleting the 5 ohm to ground, change it to 20 or 25 ohms. It would be a few dB hot above 6 kHz otherwise.
Ok, now a quick word about the issues with this kind of MTM conversion. MTM Tweeter response will be a little more ragged than a model done with TM baffle data would predict. First, the top edge above the tweeter is gone, changing the diffraction signature. Second, cavity effect on the tweeter's response would be more pronounced with two woofers next to it. I can't say what the difference would be without measuring the tweeter on an MTM baffle.
The final issue would be that vertical lobing is a bit narrow with that crossover point in an MTM. Optimum listening height would only be +/- 5 degrees above/below the tweeter axis.
All that said, it would probably sound ok. Just don't call it a Zaph design..."

Now, it sounds as though the issues with diffraction, lobing & cavity effect would be decreased if this were configured as a tmm. whadya think?

[jkrutke]

Using the search function on the PE forum I found some references to conversion to an mtm.

Well I guess it wasn't deleted after all. A few of my posts regarding MCM products have been deleted in the past, so I suspected as such again. Maybe the default search date range does not cover everything that's in the active forum.

Maybe PE is now leaving posts about MCM products stay. In that case, I thank them and apologize for assuming it was deleted. It was always cool how Madisound allows discussion of competitors products. (back when the Mad board was alive)

Now, it sounds as though the issues with diffraction, lobing & cavity effect would be decreased if this were configured as a tmm. whadya think?

Yes, if it were a 2.5 way TMM. However the crossover for that blows the budget and forces a full 6dB of BSC.

[Ray_D]

Zaph's Bargain Mini

Here are a couple of pictures of one (of five) of the Zaph bargain minis that I built.

They sound great.

I made the backs removable rather than the fronts for cosmetic reasons. They are covered with cherry veneer and a wipe-on poly finish. This set is for my daughter. My son wants a set but darker and my sister wants a set in oak. I am also building two more for computer speakers.

[JonP]

Nice... The cherry really came out good.

I've got to get off my butt and order the tweeters to finish the part list.

What do you have underneath them?

[Ray_D]

A Pair of Inactive RS225 Woofers

Those are the woofers from a set of RS225/RS150/RS28 speakers I built but are in plain MDF currently. I built them in two parts for ease of moving and so I could experiment with different drivers, which I haven't done. They are inactive currently. I have an RS315HF sub which I sometimes use with the small speakers; but, they sound very good alone.