Blueprint 1803 applications! (1 Viewer)

[Jack Gilvey]

I got it, Gomer. I had heard the term before, it's basically opposing the motions of the drivers, right, to cut down on reactive forces?
Hey, FRC sounds has a 20 driver minimum...I'm sure we could get 20 orders together and design our ultimate driver.
[Edited last by Jack Gilvey on October 31, 2001 at 05:55 PM]

 

[Gomer]

Scott is pretty cool and is good at what he does. If I was to pick a driver, it would be a 12-15" sub that would be sealed. It will only need a box size of 1.5-2ft^3. with a Q of .707, it would have an f3 around25-30hz (before any room gain/boost). Of course killer x-max.
The trade off...super inefficient (like 80db.....I can live with a crown powering it...and the WAF would be great!

 

[Jack Gilvey]

I would also trade efficiency for lower Fs, but I think Vas would also come up.
All-in-all, though,I think the 1803 is a very nice balance of trade-offs, and it probably isn't far from my ideal.
It would be nice to have a low a super low Fs/large Xmax driver, efficiency/Vas be damned, specifically for IB use in multiples.
[Edited last by Jack Gilvey on October 31, 2001 at 06:15 PM]

 

[Gomer]

I believe it is hoffmans iron law that says of three charateristics(box size, extension, and efficiency), you can choose two and you are stuck with the third. I choose box size and extension=)

 

[Gomer]

This is from the parts express forum.
I believe that the other driver is the maelstorm. http://www.personal.utulsa.edu/~jerr...8/DSC00018.jpg
if you want to see other pics, change the 18 to a number between 01 and 38
Enjoy

 

[Chris_Brunhaver]

Boy, the kid on the PE board sure built a crappy box for that monster. Still I have to give him some credit as he's still way ahead of me when I was his age as far as speaker building goes.
[Edited last by Chris_Brunhaver on November 01, 2001 at 04:57 AM]

 

[Brian Bunge]

Wow, this thread really took off yesterday afternoon! I'm getting more and more excited about this driver! FRC Soundworks does sound interesting. I noticed they have a price for a single 12" driver but then also have multiple driver pricing. Maybe the 20 driver minimum is for them to product something to individual specs.
Thomas,
Can you explain what you mean by comb filtering?
Thanks,
Brian

 

[Jerry Parker]

Um yeah, thats my sub that you are looking at... Yes I do know the box is really crappy, but it is a test box and i belted the whole thing out in under 5 hrs. The driver sitting next to the 1803 is an MCM 18" pa driver that is used in my brother's subwoofer.
http://www.personal.utulsa.edu/~jerr...8/DSC00038.jpg
There is a picture of both boxes. At moderate excursion levels on th 1803 i get port noise, so my final box will probably be 12cuft tuned to 18hz. I will use at least a 8" pvc pipe for the port. I might even make it as a sonotube sub...
You guys must realize that my projects are limited by money. This was a huge investment for me (250 dollars) for the 1803. I dont have access to a table saw and a router right now, so I have to have homedepot cut the wood for me...
Here is a picture of the speakers I built using proper tools:
http://www.personal.utulsa.edu/~jerr...s/DSC00009.jpg
Keep in mind guys, Im only 18 years old, and I learned 90% of what i know about speakerbuilding off the internet....

 

[Dustin B]

Your way ahead of where I was at 18, and that was only 5 years ago. It wasn't until I was 19 that I bought a Pioneer HTP100. God that thing was crap, but at the time I thought it was great. Things have improved just a little bit since then

------------------
Dustin
[email protected]
My Adire Tempest Sonosub

 

[ThomasW]

Brian
Comb filter effects for audio are where reflected frequencies that are out of phase, cancel nonreflected similar frequencies. As a result the response plot has holes in it, so it looks like the teeth of a comb.

 

[Brian Bunge]

Thomas,
Thanks! I knew there was a reason it was called "comb" filtering!
Brian
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[Dustin B]

I decided to try and play with this driver in UniBox. But I don't know what to enter for Le and series resistance.
Also, what are you entering xmax as. The web page says 22.5 while the dumax of the 1503 said 26. something if memory serves.
Also someone wouldn't buy chance know the series resistance of the Maelstrom?
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Dustin
[email protected]
My Adire Tempest Sonosub

 

[Isaac C]

Hi Dustin,
quote: I decided to try and play with this driver in UniBox. But I don't know what to enter for Le and series resistance.[/quote]
It is my understanding that series resistance stands for the output impedance of the driving amp. 0.1ohm would be a reasonable estimate (which would make for a worst-case, I guess) or you could use the value from driver nominal resistance divided by damping factor (at that resistance)... plus of course cable resistance and so on.
Regarding Le, this value does not matter since it is likely that an active xover would be used. However, Le would be useful in constructing a more exact model to see the effects on impedance phase etc.
I would use the Dumax-values
quote: Also someone wouldn't buy chance know the series resistance of the Maelstrom?[/quote]
If you mean the DC resistance of each coil, it's 6.8ohms.
HTH
Isaac
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Subwoofer Simulator
Factor Conversion Tool
[Edited last by Isaac C on November 02, 2001 at 04:03 AM]

 

[ThomasW]

I'm pretty sure the 1803 and the 1503 use the same VC. I measured the Le of one of my 1503's and it's 4.28mh

 

[Jack Gilvey]

Quote:



Um yeah, thats my sub that you are looking at... Yes I do know the box is really crappy, but it is a test box and i belted the whole thing out in under 5 hrs. The driver sitting next to the 1803 is an MCM 18" pa driver that is used in my brother's subwoofer.

The one thing that I noticed was the small port, but your final design looks much better. I'm leaning toward 14ft.^3 with a 10" port (which, at almost 40" long, I hope doesn't cause problems).

 

[Dustin B]

I don't think 6.8 ohms is the right value to put in the series resistance field of unibox for the Mealstrom. From the drivers that come with it with specs already entered, the TC Sounds 12" has it set to 0.4ohm, the Stryke 12" has it set to 0.1ohms and the Lambda 10" has it set to 0.1 ohms.
When I set the value to 6.8 for the Maelstrom and 7.2 for the 1803 I get a really big hump in the 30hz range for both drivers when tuned below 20hz. When I set the value down to below 0.5 ohms then that hump disappears. Can someone tell me what I should be putting in that field for both drivers?
------------------
Dustin
[email protected]
My Adire Tempest Sonosub

 

[Jack Gilvey]

I don't know what it should be, but I can't imagine that the output Z of a solid-state amp combined with the resistance of even a long run of cord would come anywhere near even 1 ohm, it's likely a fraction of that.
I don't believe that that number has anything to do with the DC resistance of the voice coils, btw.
[Edited last by Jack Gilvey on November 02, 2001 at 11:04 AM]

 

[Rick Chwiendacz]

Jack's right - it has nothing to do with the driver. It's the sum of the resistance of the speaker wire and the output impedance of the amplifier. In most cases, especially with subwoofers, this will be in the realm of 0.1 ohm or so.
If you really like, you can look up the output impedance in your amplifier's manual, and then measure the resistance of the length of wire you plan to use and actually calculate the series resistance yourself. For 99% of cases though, leaving it at 0.1 ohm is fine.

 

[Isaac C]

When I set the value to 6.8 for the Maelstrom and 7.2 for the 1803 I get a really big hump in the 30hz range for both drivers when tuned below 20hz. When I set the value down to below 0.5 ohms then that hump disappears. Can someone tell me what I should be putting in that field for both drivers?

0.5 would be a good value to put in as the worst-case scenario. Anything higher, meaning below-average quality amp and cables, would increase Qes and Qts, which would explain that hump when 6.8 was used
Isaac
------------------
Subwoofer Simulator
Factor Conversion Tool

 

[ThomasW]

The BluePrint 03 series drivers don't have dual coils. They have a single VC, and the Re is 3.94 ohms