The Pencil: inspired by Ohm Micro Walsh Tall

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Juspur used the smaller Nomex HDS drivers. Peerless still makes them in poly, glass, and aluminum. They(the nomex) are still in stock at SpeakerCity, I believe, but the poly and glass are amazingly close on-axis, and all are similar from the back.

Generally speaking, all the HDS drivers will make a good Pencil(I know it's confusing, others have used pencil, pensil,etc as names). You will probably drop the crossover as you go larger.

As even Ohm has gone to smaller drivers on top with below-step woofers below, I would agree with Chris that you can stick to the smaller unless you need the maximum output of the larger ones.

It's a great project, and even if you tire of them, an HDS will never embarrass you in a 'normal' speaker.
 
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By the way, Madisound has the poly 6.5" for 29$, you cannot beat that, except maybe with the tg9 for 9$ if you want to try a mini.
I have used the nomex 6.5 and the tc9 this way, both worked well, the little one went higher, the bigger much, much louder.
Hmmm...maybe the 6.5 on the bottom, the 3.5 with a baby audax on top....that's 81$ for a pair. Darn sales!!
 
Thanks for the information about the drivers still being available. are there any drivers that would do a better job? What about the tweeter?

Critofur -- Do you think that The Pencil sounds just as good or better than the 1000 or is it closer to the 2000? What's your overall opinion of the sound quality of the Pencil?
 
Damnit, I can't find it now, but, a guy from Sterophile went to the NY Audio Show and after listening in the Ohm room he was heaping some high praise on them, talking about how impressed he was that those ~$2,000 speakers sounded better than other rooms with speakers costing upwards of $20K.

I think it had been here, but they must have edited those comments out or something:

Our Final Binaural Video Report from the NYAS | Stereophile.com

If you watch the video and go to 12:20 you can still hear some comments about the Ohm speakers.

My honest opinion, and not because I was connected with Ohm for a while, is that the 1000s are going to be significantly superior to the "Pencils" because they [the 1000s] have substantially more bass output (I know this as I own and have tested both woofers, and, I know about some tricks that the Ohms use to enhance the bass response).

As to the midrange however, the "Pencils" would not nesc. be inferior, depending on the quality of the cabinet construction and the crossover design.
 
The drivers: Peerless 832873 and Morel MDT-40 (tweeter) are out of production.
Would the Peerless 6.5 driver from Madisonsound for $29 or the wg9 for $9 (or others) be almost as good, just as good or better than what was originally used? Which driver (exact model number)will give the same or better result? What tweeter (or does it matter) will match the mid/bass driver for best results?
I'll just use the simple crossover as suggested, and move the crossover point up or down accordingly.
The cabinet will be the size suggested or changed to accommodate the new driver. What crossover orcabinet changes can make this a better project?
I'm just a novice so any suggestions would be helpful....
 
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Since the 6.5 is cheaper now than the 5 1/4 or even the 4incher, I guess you'll have to suffer with a bit more bass, sensitivity, and loudness.

Use the 6.5, put it in 14, Mad's port 2"x5.5"(up to 8" in some placements). If you use the same form as Juspur's 5 1/4 or thereabouts put the port in the bottom and stuff almost as high as the port in the box.

Don't get hung up over Peerless part numbers, there are always identical and functionally similar items with varying numbers-oem, different runs,cosmetic differences, etc. And any competent tweeter can do this easy job.
 
I can tell you that the Peerless 6.5" woofers (I've only tested the Nomex version) are a good choice, as is the Seas ER18RNX (if you can fit them in your budget).

Most woofers are not good for use in this way (like Ohm Walsh or "Pencil" type speakers). In fact, most are very poor for this application. You could test 20 different woofers and find only one is good (a process I have actually done myself, it can get quite expensive and be quite disappointing until you find the one that's good).
 
Don't get hung up over Peerless part numbers, there are always identical and functionally similar items with varying numbers-oem, different runs,cosmetic differences, etc.
Not always true. Have a look at TC7FD00-04 and TC7FD04-04. Looks like the same thing until you see the frequency response - totally different beast.

The Peerless parts that show up now and again as 'buyouts' often have strange responses or significantly simpler/smaller/cheaper motors. Probably made to order to satisfy the requirements of a product run, then the spares get flogged off and find their way to us via the usual middle men as 'buyouts'.

The Peerless 830874 isn't one of those 'made to order' products afaik, instead part of the here-to-stay HDS line, so should be good.
 
The Peerless 830874 - at $29 how can you not try it?

However, I'm still hoping that someday somebody will want to work with me here in the Columbus area, because I know of some moderately affordable drivers which are better, and a handful of specially good tricks when it comes to making the speaker better than what you'll normally find being made... I'm just not good at solo projects, I need a team to collaborate with. I had a blast working with Ohm designing the MicroWalsh series and I've had another project on the back burner for years that I'd like to see come to fruition before I get too old to appreciate it.
 
I have more questions about putting this together. I don't have a lot of experience but I can and have put speakers together.
I got a pair of Peerless 83084 mid/bass 6.5 driver (from Madisound-- thanks boswald -- got the last 2 on sale).

I'm planning on using a cabinet size of (internal space) 7 x 8 x 36. Would like to port it from the bottom

You stated :
"Use the 6.5, put it in 14, Mad's port 2"x5.5"(up to 8" in some placements). " What do you mean by the part underline?

I know that the cabinet size affects the bass, but in what way? A cabinet size too big will do . . . ., too small will do...., does it affect the midrange?

The tweeter that I plan on using is the Seas Prestige 27TDF (someone on line used this tweeter with the Peerless driver. I haven't bought it yet--any opinions would be helpful. I'll try to keep the crossover like the one in this article or ... .

I'm planning on starting this project in a few weeks, so any comments or suggestions would be helpful.
 
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I meant 14 liters, about a half cubic foot. You'll have about a cube after bracing, port, etc.
You're getting in to quarter wave territory with that length, and your drivers will be rather high.
I'd suggest leaving off about 8", your tweeter will end up over 33". If you port on the bottom, you can lose another couple inches. I'll do some calculations later on tunings/ structures.
 
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You will not be able to use a crossover designed for a conventional arrangement, and you will be want to cross fairly high so you do not need a tweeter that trades high freq dispersion to go lower.

The crossover need not correct for a change from 4pi to 2pi. Just filters and tweeter level.
You might look at the SB19 or other 3/4" tweeters that have great top octave response.
The hardest thing in this project will be dealing with that truncated frame.

How low(long) are you willing to go? My Walsh 2s are 31.5" on little feet. 34" if I use casters.
The box is 24" outside height. The tweeter 2" from the top.
I have nomex and poly/paper on hand in that size hds, so I can do a test mockup if needed.

As for the relationship between box size and bass, more box can mean lower bass, small size can mean more power handling, go too far in either direction and you lose control of the opposing characteristic, too small a box and you've got a loud speaker lacking lows, too large and you can go very low, but only quietly.
Box volume will not affect higher notes unless you get really carried away with small.

Draw up a couple shapes you could live with, try to keep the volume down a bit(18-20liters)
and we'll see how to mitigate(or use) the tubeness of it all.
 
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The 38" includes the 'can' and feet/casters, it's probably 30-31" outside, 28-29 inside the box.
It needs to be stuffed more as the proportions get more extreme, to suppress the peaks/dips caused by end loading the tube.
Martin King's TL alignment tables essay gives an explanation with a few examples, without going too deep into the math.
With the larger cross section (that you will have) the proportions are less severe and you can stuff the bottom fourth heavily(or third if you move the port up to the side) and leave the rest open(line the walls if you like).

Because of the enclosure shape what you have will be what we are calling a mass loaded transmission line, where a port and its air mass are together tuning the box, functioning similarly to a longer step-tapered line.
 
Thanks for all of the information that you provided.
The SB=19 or the Tang Band 28-847SA Dome Tweeter will be used. The Peerless only goes up to 4000, so should a crossover point be 3500 or 4000?

I was thinking of using just a high pass capacitor (metallized polypropylene) to the tweeter. For the Peerless driver, I'm still looking at a simple low-pass filter.

As far as the cabinet size, I'll be using 20-24" or whatever is recommended for this size driver.

Any suggestions would be helpful.
 
Thanks Critofur and Boswald for answering my questions on this project. I used one of the "building speaker cabinet" web sites to help me determine how big my cabinets should be.
After reading this site with the crossover I'm going to use a simple first order high pass filter (a capicator) to the tweeter. Woofer (full range), no crossover (still learning and got a long way to go--thanks for being patient with all my questions)
 
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