Jump to content

UPDATE 04-04-15, Single Driver Experiments


Recommended Posts

During Father's Day weekend was not a good plan to complete this project. Much was accomplished, but they're not done.


The 4 enclosures are essentially glued together. I decided to glue on the motor boards and make the backs removable. Rather than screw into MDF, I installed glue blocks (similar to inside Heresy speakers). The cutting, gluing & clamping times 4 took much longer than anticipated. There are only so many clamps.

The photo shows an enclosure before the glue blocks are installed.

Edited by DizRotus
Link to comment
Share on other sites

This shows glue blocks clamped in place.

SWMBO was distressed to see the Home Depot pine trim used to make glue blacks is from Chile. Zoom in on the photo and you can read the sticker on the piece used to protect the enclosure from the metal clamp.

Edited by DizRotus
Link to comment
Share on other sites

Wood screws and MDF are a bad combination.

Rather than glue the components in place, I'm using machine screws and lock-nuts to hold the drivers, port tubes and terminal cups in place. I made gaskets from some thin closed cell foam to seal the components against the enclosures when the screws are tightened. There will also be a gasket under the back panel that will be screwed into the glue blocks with wood screws. I've not yet drilled holes in the rear panels or punched holes in the rear gasket shown lying on the glue blocks

The foam panels will be trimmed and attached with spray adhesive to the sides, tops and back panels

I over estimated the number of foam panels. The surplus will eventually be offered free (I'll pay shipping) to the forum as pay it forward because the drivers were donated to this project by Andy, aka, "Klipschguy" on this forum.

Note the dust cap on the driver in the photo. Two of the drivers had dented dust caps. Parts Express replacement dust caps were all too large for these small drivers, except the caps for Bose 901s. At $0.69 each, I bought six.

Edited by DizRotus
Link to comment
Share on other sites

The 40-1197 were rebranded FE-103s. The first version used a tan cone and a slightly darker tan plastic fabric surround. Most I had measured an Fs of about 75 Hz, which for a 2 1/2 inch cone is pretty amazing. I used them as mids in my early days of speaker building. They are pretty good up between 500-4500 Hz and then go into break up, and the response becomes rather wavy. The tan surrounds tended to 'slump" after about 10 years or so, don't know about the black versions.

Link to comment
Share on other sites

I have all 4 speakers operating. An update with photos was planned, but I can't easily resize the photos that document the progress.

Upon initial comparison with the rear horn enclosures there is a noticeable difference, although it's too early to say better or worse. The larger rear horn enclosures appear to have a more full bodied sound. No matter the final subjective absolute ranking, the smaller enclosures win on the basis of space occupied (WAF), ease of placement and ease of construction.

One pair has the "egg crate" foam panels on all inside panels except the motorboards. The other pair has no foam. My initial impression is that the foamless pair sounds brighter than the foamed pair. None of the 4 drivers has any playing time, despite being old (they've languished in their boxes for years). Perhaps comparisons should wait until a burn-in period has elapsed. .

Is there a reliable (no spyware, etc.) photo resizing program available for "free" download and compatible with Windows 7?

Mike, my computer guru, worked diligently to remove some "double secret" viruses that were slowing my computer while avoiding detection by several anti-virus programs. Unfortunately, he also removed a program that allowed me to right click on a jpg photo and immediately and easily resize it to make email, posting, etc. easy.

Apparently. it was part of a Microsoft Powertoys software that had been added (probably by Mike).

I absolutely need the ability to resize photos for my business; it also comes in handy when posting photos to this forum.

Your enlightened suggestions based upon personal experience are appreciated.

EDIT @ 2:39 PM EDT

With prompt and beneficial help help from jhoak and Don Richard, the photo resizing issue was solved.

A photo of an operationally completed (finish to be done later) speaker is now attached.

Edited by DizRotus
Link to comment
Share on other sites

The inside of a box with no egg crate foam and the partial port.

By using machine screws and nuts to attach the drivers, ports and terminal cups, I'll be able to remove the components to clean up the exteriors prior to applying a finish.

Edited by DizRotus
Link to comment
Share on other sites

The interior part of the port is in place. Another complete port is on end outside the box. According to the instructions and formula that came with the "Precision Port" from Parts Express, The port as configured is 2" in depth with a 2" diameter.

Edited by DizRotus
Link to comment
Share on other sites

The two boxes with the older Taiwan drivers have the foam. For now, the other two boxes have no foam. After listening to both versions, I'll decide whether to use the foam.

Edited by DizRotus
Link to comment
Share on other sites

The backs are attached by screws into the glue blocks. This allows the machine screws and nuts to be to tightened before the backs are screwed into place. After taking the photo, I decided to invert the terminal cups so that the terminals point down.

The most significant difference between the two pairs is the egg crate foam. Less significant differences are: age, country of manufacture and dust caps. I repaired the dented dust caps on the Korean drivers with Bose 901 dust caps from Parts Express.

Recognizing the inability to compare apples to apples, as well as the lack of burn-in, the following gross comparisons are made:

1. The two pairs are easily distinguishable by sound;

2. It's too soon to say which is better than the other, but I'm leaning toward the foam/Taiwan pair; and

3. Each pair sounds very good;

4. Each pair is noticeably different from the rear horns; and

5. Irrespective of the final decision regarding the BR boxes vs the rear horns, the BR enclosures make more sense.

Edited by DizRotus
Link to comment
Share on other sites

As you can see, this is a state of the art test project. After a burn-in period and doing some "blind" A-B comparisons using the younger ears of my son and the better hearing of SWMBO, I'll post a video comparing the BR enclosures to the rear horn enclosures.

For now, all four BR boxes are playing at once to burn in the drivers, as I listen to the Tigers vs Bosox game.

Playing music from all four at once sounds pretty good to me, but I suspect Dr. Who (Mike) would point out problems with comb filtering and other acoustic phenomena that are well beyond me.

Any opinions/theories on the pros or cons of the egg crate foam as used in these enclosures are welcomed. Intuitively, it seems as though the foam would help.

Edited by DizRotus
Link to comment
Share on other sites

Ten full 12 x 12 foam panels and usable partial panels that probably make up 4 - 6 more panels. Free to first forum member to reply by post, PM or email. I'll even pay the postage.

Edited by DizRotus
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...