Maelstrom 21" With 4 - 2100 Gram 18" Passive Radiators

57940 Views 180 Replies 23 Participants Last post by Mike Cason, Jun 1, 2010

Mike Cason

Discussion Starter · Nov 21, 2009

Here is my build thread for the Maelstrom 21. I'll try to provide enough quality pics during my build for you.

I'm using Kevin's Maelstrom 21"er with the passive radiator design. I normally don't like building a passive radiator sub with a Qts over .4, but it is so close, I won't have a problem.

Here's the deal....23" x 23" x 60"; 13 cubes and 15.5 hz box tuning. With the typical passive radiator design there is more of a roll off but at this already low box tuning, I'll have more than plenty of bass. I needed the height to match my main speaker's height and get the cabinet volume I need. Better WAF here.

I just picked up the pallet of materials from my mill. My construction material is 1.25" mdf. It looked like I had ten bags of concrete in my truck going down the road. In the roll of plastic, I've got two sheets of Pionite black slate laminate to match all of my other speakers.

Cabinet resonance with this thick material; I don't think so. Moving it? Now that's another challenge.

Just got back from Houston with the materials so here is the first build pic:

Read more: So where are the Maelstrom-X 21" Build Threads! - Home Theater Systems - Electronics and Forum - HomeTheaterShack http://www.hometheatershack.com/for...elstrom-x-21-build-threads.html#ixzz0XWvNWnLo

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141 - 160 of 181 Posts

Veltinorian

· #141 · Jan 24, 2010

Hi Mike, as it itches me to build sthng better than what i already have, do you expect reaching the PR excursion limits, when lets say me only using one PR or maximum 2PRs with a 15inch tempest X2 for example running at 500W+ in a 250 Liters enclosure? Or in other words, is it better to choose a PR with lower Cms when using such a powerfull driver? I came across PRs with Cms from 0.2mm/N to 1mm/N (even though different, Xmax are comparable for all those passives) ?

Thanks, Veltinorian

Mike Cason

Discussion Starter · #142 · Jan 24, 2010

Veltinorian said:
Hi Mike, as it itches me to build sthng better than what i already have, do you expect reaching the PR excursion limits, when lets say me only using one PR or maximum 2PRs with a 15inch tempest X2 for example running at 500W+ in a 250 Liters enclosure? Or in other words, is it better to choose a PR with lower Cms when using such a powerfull driver? I came across PRs with Cms from 0.2mm/N to 1mm/N (even though different, Xmax are comparable for all those passives) ?

Thanks, Veltinorian

I would use two prs that are of equal size per driver or larger. If you are looking at using 2 Tempests, I would use 4 passives. The Cms of 0.2mm/N to 1mm/N is very low, even though the Xmax is comparable or higher. If they have a similar Xmax, two passives per driver should work well. It would be hard to reach full xmax when using two passives per driver. I have 4 15" passive in each of my mains that have only two 12" drivers each.

I would get someone to do some modeling for you to compare the low Cms for your application. I don't have that modeling software. I think Mike P. can do that.

I think Dan Wiggins of the Adire Audio days sold the flat MDF passive radiators that Acoustic Elegance builds. They are low Cms. That's what I have in my sub. If my memory serves me correct, Adire sold the Tempests, Bramah, and another sub.

The Cms of my 18" 2100 gram passive is .9 and I have a 3" point to point excursion. I'll never reach those limits using the four passives I have with the Maelstrom 21".

Dayton has a sub driver with a matching pr; Peerless XLS drivers had their own XLS passives to mate with their driver. Peerless also had their small SDS line of 6.5 woofers that had the Peerless 830880 passives to mate with their driver. Kevin has some 21" prs to match his Maelstrom 21" driver.

The key is to model out your design before you build your enclosure to ensure you will get the response and box tuning you are trying to achieve. IMHO, a properly built PR sub can't be beat, even though I haven't listened to good transmission line sub yet.

Mike

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sub_junkie

· #143 · Jan 25, 2010

Mike, are you still going to sell your 21" Mal?

Mike Cason

Discussion Starter · #144 · Jan 25, 2010

I sold my extra Mael 21" driver and pulled my new sub off of the market, but anything is possible. This beast gets so incredibly low, my wife doesn't like it. She has been ok with all my builds for the past 15 years, but the low end is just way too much for her. pm me or email me if you have any questions. Hope you are doing well....

sub_junkie

· #145 · Jan 25, 2010

You had two 21" subs? I didn't know that :bigsmile:
Have you taken any in-room measurments with it yet?

Mike Cason

Discussion Starter · #146 · Jan 25, 2010

I tried, but when I ran the subwoofer for testing, I had to hold onto the walls to keep from being knocked over. Couldn't keep the microphone steady. When I get some extra help, I'll try again......

Really, I'm not set up for in room testing.... I was able to check the box tuning with Linkwitz test cd, and I'm right at 15 hz.

sub_junkie

· #147 · Jan 25, 2010

Man...now your really making me want a Mal 21...I hope I can win the giveaway for the 21". That would make my year. Then my dad could have my Mal-X, and we can shake the neighborhood down while watching movies :bigsmile:
If I could be blessed enough to win the 21 (lol), I would definitely try passives with it. Sounds like it would be awesome as you wouldn't have to worry about port noise, chuffing, etc...

Mike Cason

Discussion Starter · #148 · Jan 25, 2010

sub_junkie said:
Man...now your really making me want a Mal 21...I hope I can win the giveaway for the 21". That would make my year. Then my dad could have my Mal-X, and we can shake the neighborhood down while watching movies :bigsmile:
If I could be blessed enough to win the 21 (lol), I would definitely try passives with it. Sounds like it would be awesome as you wouldn't have to worry about port noise, chuffing, etc...

It is worth the extra money to use them. The passive radiator design has its deep and well respected bass of its own. With as much air as this driver moves, I would expect to hear something from the ports. Vance Dickason states in his Loudspeaker Cookbook that an improperly built or other unwanted noises from your loudspeaker can be amplified by as much as ten times through the ports. You also eliminate the port resonance as it can't exist. Hope you get it son.....:T

sub_junkie

· #149 · Jan 28, 2010

Mike Cason said:
It is worth the extra money to use them. The passive radiator design has its deep and well respected bass of its own. With as much air as this driver moves, I would expect to hear something from the ports. Vance Dickason states in his Loudspeaker Cookbook that an improperly built or other unwanted noises from your loudspeaker can be amplified by as much as ten times through the ports. You also eliminate the port resonance as it can't exist. Hope you get it son.....:T

All right now you've convinced me to use passives on my next build depending on what it is.
Actually, the M-21 could make an awesome Birthday gift as it is my 16th on the second of February! :bigsmile:
I just can't believe how big the M-21 looks compared to your 18" passives. I wonder if the subwoofer market will keep going with bigger subs? Or will this be about the biggest you will see?

Mike Cason

Discussion Starter · #150 · Jan 28, 2010

sub_junkie said:
All right now you've convinced me to use passives on my next build depending on what it is.
Actually, the M-21 could make an awesome Birthday gift as it is my 16th on the second of February! :bigsmile:
I just can't believe how big the M-21 looks compared to your 18" passives. I wonder if the subwoofer market will keep going with bigger subs? Or will this be about the biggest you will see?

Hi there SJ....I think a better way to para-phrase your comment would be to say "the biggest you would ever need"!

Watching more movie material last evening, again I had to open closet doors by the front door and in the hallway to keep them from ratteling in their strike plates from the low frequencies trying to bounce out of them. I'm talking at very low volume movie watching! Yea, any larger would be problematic throughout the home and even for a dedicated HT room, it is more than plenty of bass. That's not a phrase I thought I would ever be putting in the forums.......:whistling:

sub_junkie

· #151 · Jan 29, 2010

I would never want anything bigger than a 21" sub. Its just huge.
I have the same problem with the doors rattling while they are shut. And rattling the pictures :bigsmile:

Mike Cason

Discussion Starter · #152 · Feb 1, 2010

2

Raven....I've finished the grills now. I've just got to get creative with my gold nameplate to put on this one. I've named my speakers the "Cason II", which is engraved on the name plates on the rest of my builds, but this subwoofer warrants a more suitable title.

SJ...you are creative....help me out with a name.....

I was thinking of having the engraver put the Cason II; with the words "The Ultimate" under it. It's quite an accomplished subwoofer and keeps getting better with break in!

Here's a finished picture. It now has a better WAF.

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sub_junkie

· #153 · Feb 1, 2010

Hmm. Its hard to think of names for other people due to their different mentalities/likes. I like the Cason II part, but "The Ultimate" might be able to change. Do you have anything that you would like to name it after? Like an airplane, movie (anything in a movie), car, gun, anything like that??

I really like the look of it with the grills on. It looks like a really clean store bought sub with 10,000 times better performance :T

Mike P.

· #154 · Feb 1, 2010

Cason II, and underneath that, Ultimate 1.1

Mike Cason

Discussion Starter · #155 · Feb 1, 2010

Mike P. said:
Cason II, and underneath that, Ultimate 1.1

Thanks Mike...."We'll make that dog hunt!" I like the 1.1.....It does leave room for change like software versions, though I don't envision ever needing to try to outbuild this one.

SJ.....Thanks....It certainly doesn't look like a garage made sub anymore.

You are also right about the 10,000 times better part. I was in a Frys store last fall and as usual strolled their HT display rooms. It is something I do every time I visit their store to hear the latest offerings. They had a Velodyne $800 sub that was so incredibly horrible sounding, it almost hurt my ears listening to it. The sales person was so proud of it and they have a certain degree of sound treatment in the room, unlike I do yet.

Three words are very fitting here....DIY & Passive Radiators....just my opinion...

You all have a fantastic year!

sub_junkie

· #156 · Feb 1, 2010

Mike P. said:
Cason II, and underneath that, Ultimate 1.1

Souunds good Mike :T
Last night after I posted, I was thinking of something along the lines of 1.1 to. :rubeyes: Strange...

The only store bought sub I've seen that sounded half way decent was a Klipsch 12" or 15" at best buy. It was clean sounding, but when it was taken up to higher volumes, you could hear mechanical noises for some reason. Maybe it was just a defective model, but maybe not... The Klipsch sure wasn't worth what it had cost to build a Mal-X like I did.

Mike Cason

Discussion Starter · #157 · Feb 1, 2010

sub_junkie said:
Souunds good Mike :T
Last night after I posted, I was thinking of something along the lines of 1.1 to. :rubeyes: Strange...

The only store bought sub I've seen that sounded half way decent was a Klipsch 12" or 15" at best buy. It was clean sounding, but when it was taken up to higher volumes, you could hear mechanical noises for some reason. Maybe it was just a defective model, but maybe not... The Klipsch sure wasn't worth what it had cost to build a Mal-X like I did.

That's why I DIY.....

Years ago when I decided I wanted a high end audio system, I browsed the premier audio stores only to find Mercedes Benz pricing on fair to decent sounding speakers. I was buying a name with a pretty wood or veneer speaker attached to it. I was determined to spend as much time on the web and reading materials to build my own, no matter how many builds it took to get them right.

Mike Cason

Discussion Starter · #158 · Feb 3, 2010

Woops....I started another build. :heehee:

A premier center speaker....I have most of the materials except a couple of woofers which will be here today. I'll probably start a build thread for it....The initial cabinet is glued and clamped. I'll be using a pair of the Hi Vi D10G 10" Kevlar woofers, my Davis Kevlar midrange driver and my Hi Vi RT2II planer ribbon tweeter. I had all of the crossover parts in stock and it is almost finshed.

The new nameplate has been ordered for the sub....Ultimate 1.1

.....when does it all end......:blink:

sub_junkie

· #159 · Feb 3, 2010

A center channel with 10" woofers???? Are you crazy man?! :coocoo:

dyohn

· #160 · Feb 3, 2010

You might want to start a new thread in the DIY Speakers section for your new build...

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