Pete B
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Posts posted by Pete B
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Did they go open circuit or how did they fail?
Some people are able to repair dome tweeters if it is just a broken wire.
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The Boston Acoustics A-100 for a well thought out 10" 2-way reaches into the low 40s on bass:
And the A-150 for a 10" 3-way.
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Built to a price point yes of course and not a very good optimization IMO.
There are 10" woofer systems that reach to the low 40s, and in the 2ax you pay for a 3way,
Steve has also commented about the 2ax.
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If you look at the crossover schematic for the AR-5 you might notice that the woofer inductor
is much larger than in the 2-ax which provides much more baffle step. I'm not surprised that they
sound so much better. I've spoken before about how I dislike the 2-ax so again not surprised by
your observations.
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It has been working great without any further issues.
Here is the plate that I designed. I've printed 3 of these and they all came out just fine:
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This printer comes with a test dog to print, it did fine for the first 80% but became
stringy for the last 20% which indicated under feeding. There is a known issue
with the feed tube pulling out or not being fully seated. This guy shows how to
fix it and suggests about $3 worth of upgrade parts but I'm pretty sure mine already
has them: I fixed it without any new parts.
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Here is another opinion on the Ender 3 with concerns about the unit to unit consistency:
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That inductor is across the tweeter, follow the yellow wires to black (ground)
and white tweeter wire on the selector switch.
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Here is an interesting video on baking the PLA part for more strength, any chemists here
who might comment on the validity of this for ordinary PLA?
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I followed this build video and it went quite smoothly, it is now printing a test:
Also followed his other video on how to level the bed.
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If they were my speakers, I would cut out the "net" on the inside of the port
tube opening. About all it is good for is keeping mice out but it is not good
for deep bass output.
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12 hours ago, DavidR said:
Yes, Glenn can work magic. I'll try my best. The damage doesn't show that much being on the bottom. The only veneer I have is from a Bose 901_II cabinet. It's too dark and the grain is slightly different so I just might fill with wood filler and sand smooth and then paint that part black. I'll be happy just getting the cabs sealed and looking decent. I'm actually looking for another pair that has plastic frames for the grille material and in much better shape.
I have even used a 1/16" or bigger as needed drill to remove some material in the area that
is swollen. First set up a furniture clamp and try to compress it, then estimate how much you
need to compress it and use that size bit, clamp again and redo it until it is square. Release
the clamp and inject glue into the holes and clamp again overnight.
I should start on my 9s one of these day or years.
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The 4ohm resistor decreases the mid/tweeter output which can also be viewed relatively
as boosting the bass. The 10 uF across the 4 ohm resistor passes more HF, yes you can use any value.
The 20 ohm resistor flattens the mid/tweeter input impedance somewhat and is not critical.
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Just wanted to mention that we simply twisted the component leads and then slipped
them under the binding posts.
I selected the component values based on the input impedance curve published in Audio
magazine when Don Keele reviewed the HO312. The 4 ohm is the only important value,
reduce it to 3.5 or 3 for less of an effect. The cap boosts the high end since Keele found
it to be 5 dB down, you can try it without the cap for another variable, and/or reduce it as
needed say between 8 and 4.7 uF.
I don't remember if I measured the input impedance but I'll look for the file on my measurement
computer since it would be very easy to simulate the mod to produce a frequency response plot.
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L4 in your re-drawn schematic is .02 mH whereas in the original it is .2 mH.
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One member asked about which 3D printer I have, it is the Creality Ender 3.
This is hands down the best bargain but it is essentially a kit with a 1-2 hour build
time. I see it as an advantage since I'll learn how to make a few adjustments.
I had some trouble finding it for $200 shipped even with Amazon Prime, but thentried ebay and Creality-Direct has it listed for $204.99 shipped but will take an offerfor $200. It has a high build volume and excellent print quality once tuned up.I was tempted to buy the Creality CR-10 for $400 but mostly it is essentially thesame with a bigger build volume. -
My opinion is that if a product was originally designed with a .75" tweeter you should
stick to it when trying to stay as close as possible so that leaves you with the SB. I just
measured my AR-9 tweeter and there is an issue, I'll post the results later tonight or ASAP.
What type of shop are you going to use?
Have you noticed that ring radiators, even .75" have inferior dispersion as compared to
normal dome tweeters?
The AR-9 tweeter has a very high Fc which is part of the electro-acoustical response and,
don't laugh, but this tweeter with a 10 ohm resistor across it would probably work fine:
They would probably fail, even with the high crossover point, if you run over 200W/ch into
them at party levels. The SB is better but the Fc is way off and will require crossover mods
or compensation.
This is the 3D printer that I have on order: http://www.classicspeakerpages.net/IP.Board/index.php?/topic/10492-3d-printer-for-mods/
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I did not plan on selling the tweeter on a plate alone but if you'd like to try
them I'll make a pair for you to test out. Would you be testing it in AR-11, 3a, or AR-9
application? I expect each will need different fine tuning to work best.
I can make the tweeter plates out of wood but I also ordered a 3D printer last night.
A minor issue with this tweeter is that the diameter is not a standard metric or SAE
size so I use the next larger size and planned to fill with black RTV which should work
fine, but with 3D printing I can do any size.
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I expect someone on ebay will copy and sell it so I'm keeping quiet for now. It was not
easy finding a 1.5" midrange that would work.
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When I purchase drivers I look at measurements first when available.
I'm open to do some testing of drivers if people want to send some of the options.
I don't usually do amplitude response but you can learn a lot from the input impedance.
I'd like to test an AR-11 tweeter that has not been used in a party system with a 300W/ch amp
as mine were.
My AR-9 tweeters were used by a lady with a 250W/ch Soundcraftsman amp also used hard.
As far as the SB tweeters go, I bought them for another project. I prefer a tighter tweeter
to midrange spacing for AR speakers and chose something else for the mid/tweeter
plate that I came up with: http://www.classicspeakerpages.net/IP.Board/index.php?/topic/10245-not-an-ar-15-midrange/
If you go to the Blue Mountain or Frankenfest I'll bring this to demo:
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21 minutes ago, RoyC said:
I wasn't "complaining" about a single off the shelf tweeter. If you recall, I'm the one who came up with the "off the shelf" HiVi tweeter, which has turned out to be quite accepted. I would be much more interested in your hands-on experience rather than speculation on various drivers. It would, of course, actually require purchasing some of them.
Roy
"Them"? I already have the SB tweeters and sorry I'm not buying the MT-4121 tweeter based on
the measurements - they don't lie. They are not even the correct impedance with those high
double bumps.
My interest in this is to solve problems using what I know and the tools that I have to do
the job, it is a hobby for me and the enjoyment comes from using science to finding the best solution.
It costs a lot of money to sample all the possible drivers that one might use in a new design or as a
replacement and many designers use the data provided by Zaph at this web page - you might note
that the MT-4121 would probably be ranked a reject if Zaph ever tested it since the majority of the
tweeters here have a flat response:
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Sure, I don't know if you've ever looked closely at the lead in wires to a woofer but they
are often fine multistrand wrapped or braided around a fiber center. These are tinsel
wires. The fiber center helps provide some physical strength and to keep the wire from
kinking. Solid wire subject to vibrations tends to find a single point to flex where it
eventually breaks if driven hard enough.
There's a picture here in Section 6: http://sound.whsites.net/articles/speaker-failure.html
Most Kloss era Advent and EPI tweeters had tinsel lead in wires.
They are usually used with low crossover points such as 2 KHz or less but are always
better to have for reliability.
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48 minutes ago, RoyC said:
Pete,
This isn't a contest or a business enterprise. Collective experience and expertise is the strength of this forum. If you are ready to purchase an SB tweeter and manufacture an adapter faceplate, I for one would be very interested in your experience. Brian was suggesting changing "a couple or three drivers". I simply suggested it should be in the "mod and tweak" section of the forum.
Roy
PS Since we are being ultra technical, Kool-aid is spelled with a "k". ?
My comments had nothing to do with business rather if you are going to complain
about an off the shelf tweeter being non-original you should also complain if a "copy"
only looks the same. You can't ignore the science behind choosing a good replacement.
We can just agree to disagree.
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39 minutes ago, cARver said:
Pete,
I wanted to provide my listening experiences with two pair of AR11's I owned specifically with the tweeter. These were both recapped with original value dayton npe from parts express.
Both pair of 11's had higher output than my 3a's but lacked the smoothness of voice with an exaggerated ch~sh tones to true s sounds. I was able to pick up a pair of AR9 tweeters and installed them in one pair with an immediate natural clarity as compared to the original 11 tweeters.
This was the improvement needed to make these speakers enjoyable.
Thanks, good to know!
I pulled out my AR-9 tweeters and will take some measurements to see how similar they are.
AR TSW 910 Tweeters-Substitute?
in Acoustic Research
Posted
Dirt cheap option if you can make an adapter plate, chosen only because it is an
8 ohm metal dome. I've never seen measurements of this on so who knows if it is any good:
https://www.parts-express.com/dayton-audio-dc25t-8-1-titanium-dome-tweeter--275-045
Ideally, you'd want to match the impedance as close as you can, Fc, and passband flatness/shape.