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I know its early days but which of the two do you prefer? What are the defining features of each?
 

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Discussion Starter #83
Nice Job Clausdk....

I'm sure you can easily notice the difference in SQ between the 2...
Gotta get some real grunt amp behind that LMS... :)
Thanks.

Better amps are certainly welcome. I haven't clipped the EP4000 yet and the in room response is flat to down below 20hz without boost at 20hz.

If I get to a point where I feel amp limited I might look into it. "cheapest" hefty amp available to me is the Crown XLS 5000: http://www.thomann.de/gb/crown_xls_5000.htm

That actually seems like a decent amp, but it costs more than twice that of a EP4000. Also I was confident to fan mod the EP4000 for silent drive.

I just felt that ~+3db for that extra cost wasnt worth it with my current budget restraints.

However, if there is actual SQ to desire from getting a better quality amp I might feel more inclined.

Thoughts?
 

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Discussion Starter #84 (Edited)
I know its early days but which of the two do you prefer? What are the defining features of each?
Still working on EQ settings.

Both drivers are great. The maelstrom x performs great in the 3 cubic feet enclosure and in my room atleast I don't even need to boost 20hz.

First word that came to mind when only running the LMS in my usual solo subwoofer spot was: CLEAN souding and full!

The LMS is capable of a real tight kick drum beat with the right amount of decay, just sounds natural despite my rooms shortcommings.

When manually pushing in the cone it's quite stiff compared to the Maelstrom. Just a note, not sure exactly what that would mean for musicality.

I've spend the most time listening to music actually, in regards to dailing them in.

It's been a tripple improvement for me.

First of all having two subs is really the best upgrade so far. First REW measurements showed me no dips and the bass across our couch is much flatter with no absurd peaks and dips in either end! What a blessing. Wife complained about booming bass on "her" side...She did'nt comment on that last couple of movies and she is quick to notice boomy bass it seems.

Better cabinets. I think the new cabinets are just right for me in terms of size and aligment. The new veneer look also enhances the cosyness of our living room which needed a little warmth:)

LMS driver. Simply superb. More testing and listening to do, but so far hasnt dissapointed. Being twice(?) as expensive as the maelstrom one would expect it to perform better, which to my ears it does. It's not night and day and tbh I was very happy with the Maelstrom but the LMS just has the upper hand on SQ, which I value above pure output.

I have a friend looking into building two 18" subs. I would recommend either sub to him. If he can stretch the budget I'd say go with 2 LMS, if not - be very happy getting two maelstrom.

It's natural progression.

I started with a cheap cerwin vega sub, then a cheap 10" ported velodyne, then a big 12" ported SVS, then a sealed Maelstrom and now the king of subs - the LMS ultra!!:)

Measurement.

I've made 4 settings on my reciever I can toggle between. +0,+3,+6,+9 db. As seen here I run my subs a little hot. Getting two subs clearly allowed me to run them even hotter without it sounding bloated.

I need bass traps, but I'm not sure I can help my 30-40hz ringing. Will mid wall on either side cancel those modes?



 

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Thanks for the reply mate.

I look forward to seeing some REW graphs comparing the LMS to the M-X in the same cabinets. Would be very interesting.

I envy you guys that get lots of bottom end room gain :) No such thing in my room :(
 

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Discussion Starter #86
The purple trace is the LMS the other the Mx.

Measured right infront of the cone of each of the subs.

Quite similar to expected performance also according to unibox. Mx rolls off later, but then steeper, and the LMS rolls off sooner, but then less steep.

It's not a dramatic difference! Also bare in mind these measurements are far from scientifically correct!:)

 

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Gotta love the LMS18 drivers!

A quick glance at your waterfall suggests your room is pretty good. The modes already have a fair amount of damping - I can tell because they don't ring out dramatically. Could you show out to 300 Hz? That is important as well and you'll often see more about how the room is behaving there.

Are you thinking of mid wall point traps? You have 20 corners to do first! Bass traps are massively more effective in corners, do them first.

I like to run my subs a little hot as well. THX recommends 10 db which is about what you have. I like the start the increase a little higher than you have.

The question is now, can your mains keep up with two pretty impressive 18" subs?
 

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Discussion Starter #89
I was thinking about moving the subs themselves to mid wall positions. However, it is sounding very good right now, and WAF is way better up front right next to the main front speakers.

So unless moving the subs to mid wall position on either side of the room gives me superb benefits, I see no point. A thing to test when I come around to it though.

I do need bass traps. I have 8 panels already, hanging at various spots, but they are oly 1 inch panels so not really helping the bass alot.

I will most likely construct some panels myself using 100mm rockwool with around 1 inch air gab behind them.

I'll make some higher frequency measurements next time I bring out the testgear:)

Regarding my main front speakers they are Dynaudio focus 220. They use two 5.5inch drivers. It all integrates well right now, but certainly a larger floor stander would'nt hurt!

Running the Dynaudio's in pure direct mode, listening to CD's, they produce chest pounding bass actually, and go rather deep as well.
It was a huge upgade to get them compares to my older ones - Audiovector C2.

Down the line my goal right now is the Sonus Faber Cremona M. But I think right now, to enhance my overall experience, a larger TV is where my money should go:) I have this "big sounding" sound system and viewing on a 42" 6 year old plasma 16 feet away!!
 

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Here's a suggestion ... elevate a sub to ear level in the listening position, then move the mic all over the place. Then look over the plots and it will give you ideas on the best locations for both subs. Look for the locations that will eliminate the most dips, then you can EQ out the peaks. Add that to bass trapping and then you get a global improvement. I've also time aligned the subs (but haven't really tested the difference). Putting all that together I'm now getting the most dynamic, punchy and accurate bass I've ever managed. It's a lot better than what I could achieve before the traps. In your case, I don't think you'll get the same improvement with bigger traps because in that measurement the waterfall looks pretty good. But you never know til you try it, and I think you are best to put in as much trapping as you can.
 

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Discussion Starter #91
That's solid advice!, thanks. Great to hear that you achieved so good results.

My main concern is ringing. It appears that having two subs solved the dip I used to have across the couch, which is great!

The dips I have now occur higher up and caused by the front speakers I suppose. So I think bass trapping can help on that.

Reducing ringing below 40hz seems almost impossible with conventionel broadband absorbers. Or would require a ton of them beyond what I can get acceptance for! :)

I'll get around to making some measurements for a larger range, up to say 400hz?

Because if I can "live" with EQing the peaks around 30-40 and then treat the higher up peaks and dips I think I will be ok and it will be a real world solution with decent WAF also.
 

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Claus, I absolutely love how those turned out. Very, very nice work. The finish looks fantastic, and the glossy base is a nice touch. I still love the subtle curve of the top, and I really may steal your design if I'm able to do a dual MalX setup down the road.

So is the plan to replace the MalX's with two LMS if you decide you like it better, or are you going to keep one of each?
 

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Claus,

I saw an improvement down to about 25 Hz with 3 big floor to ceiling traps. Keep in mind that music exists mostly above 40 Hz, so I'd be concerned most about what happens from 50 - 300 Hz. Your room already looks like one that has been trapped, so I can only guess you are one of the lucky ones.

30 - 40 Hz isn't a huge concern IMO. That's getting into LFE territory and a little extra ringing there that you have will give the impression of a bit more bottom end.

Don't forget you have 20 corners in a rectangular room. So you could pick some corners that get you into less WAF trouble. A bit of creativity might pay off. Here is one trick to make them seem not so big. Place a door so that it straddles the corner (just imagine it). Now move it into the room about 6". That makes it bigger acoustically due to the depth to the corner, but visually it looks like a smaller trap because you see the width more than the depth. Now had you made it a simple triangle shape, it would look much bigger because instead of a width of 820mm you might see 1000mm. I hope that makes sense.

I think with tools like cheap mics and REW floating around, people get fussy with nice flat lines. It's not too difficult to achieve, but the eyes are more fussy than the ears. A ruler flat line looks good on paper, but if the time domain isn't equally pretty then you will still have problems. Instead I'll take +/- 5 dB up to 300 Hz with a well trapped room because I've found that sounds better. Even less flat than that can be a good result.

Here is what I got with bass traps:



You can see my starting point was not as good as yours. I wrote about it here:

http://redspade-audio.blogspot.com/2010/12/free-bass-trap-test.html

This is my before:


I tried it out with some foam I had around the house because I was not too convinced about the value of bass traps and the need to give up valuable space in my small room. The result got me hooked right away and it was a big turn around. I had considered bass traps the icing on the cake in the ideal perfectionist setup. Talk about a big change of opinion!
 

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Discussion Starter #94
Claus, I absolutely love how those turned out. Very, very nice work. The finish looks fantastic, and the glossy base is a nice touch. I still love the subtle curve of the top, and I really may steal your design if I'm able to do a dual MalX setup down the road.

So is the plan to replace the MalX's with two LMS if you decide you like it better, or are you going to keep one of each?
Thanks alot!:)

Feel free to copy the design, mine's a copy also, with minor tweaks. As someone mentioned earlier, a piece or two of cross bracing might be worthwhile, to further enhance the cabinet.

I will get another LMS down the road for sure, but I think a new larger TV, then possibly a better reciever is better spend right now since my bass is quite good now.
 

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Discussion Starter #95 (Edited)
Paulspencer,

I absolutely agree with not obsessing with a ruler flat response. When I dailed in my new sub + the old one, I focused mainly on reducing decay time.

Alot of trial and error went into the 30-40hz area, but eventually I think I got it as good as I can with my current knowledge and experience!

It's quite interesting to see your waterfall graphs and nice image switching for easy comparison!! Looks like you solved the 25hz, 40-50hz and 70hz problems, and beyond that just looks amazing really. Do you know what's causing your dips from 70hz onwards?

How much acoustical treatment did you end up with? Not sure it states that in your blog? Just those 3 big corner traps?

I think I might be obsessing a little about my 30-40hz ringing and perhaps I'm giving overemphasis to that area in regards to whats causing boomy bass in my room?

Tomorrow, if I get around to it, I'll try and make some more measurements.

Regarding my room. Right hand back corner is actually a double french door style. I think it might act as one big membrane bass trap and it certainly vibrates in some scenes during movies!

Front right corner is a set of double windows on either side, so wouldn't be possible to place traps there.

Front right corner has the one sub in it. Placing a huge bass trap there across the corner would be less a no go. I was thinking one 100mm trap each side of my TV behind the main speakers.

Left back corner is the only really good bass trap corner. However, there are 2 smaller windows there about 1.2' from the corner itself. This means I am unable to construct a large trap there.....

Basicly I'm stuck with the walls.

Ceiling is slanted, with 8 feet near the walls and 10 feet in the middle.
 

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these are my favorite looking DIY subs i have seen yet. i would really love to build a couple myself as i think they are good looking enough to get past SWMBO!!

is anyone able to pen up some cut sheets??? i have tried using sketch up but i cant figure it out.

great work again.
 

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Alot of trial and error went into the 30-40hz area, but eventually I think I got it as good as I can with my current knowledge and experience!
My guess is that if you reduce it with traps, it will give the impression of less weight on the bass. When I first tried traps, I noticed two things in particular. Firstly, it sounded like the bass had moved outdoors! It no longer sounds like that but comparatively it was the initial impression. It's a bit like when you suddenly notice the air conditioning noise in a room only when it stops. Secondly, it sounded like there was less bass, but I recognised that this was a time domain issue. It's hard to keep track when you keep changing EQ and crossover like I do, but I find I tend to run the bass a little higher. This increases the sense of punchiness and oomph in the bass and it becomes more visceral yet does not seem louder than before, even though it is. I find this more satisfying. Yesterday I had a session with some rock music and the improvement in bass punch is startling. Kick drums just have that extra attack. I think some might even find it underwhelming, the impression of less bass and as a result turn it up like I did.

It's quite interesting to see your waterfall graphs and nice image switching for easy comparison!! Looks like you solved the 25hz, 40-50hz and 70hz problems, and beyond that just looks amazing really. Do you know what's causing your dips from 70hz onwards?
Yep, that's easy .... the room!

As you probably know already, the modal range is about 40 - 300 Hz. Above that the modes are spaced so close that they smooth out. So we call that point where they are close enough not to matter the Shroeder frequency.

How much acoustical treatment did you end up with? Not sure it states that in your blog? Just those 3 big corner traps?
Just those 3 huge and horrendously ugly things. The rear one is now covered with a sheet. They are all about 2.4m high and about a foot thick to make up for being foam. All made out of what I had on hand. I'm going to experiment a little with seeing what happens if I squash the foam together to make it more dense. I may soon get some rigid fibreglass and see how it compares. Unlike most bass traps, I plan to use mine as midrange absorbers as well. The two front traps - one has a foam single mattress on the front and the other a small double. That's a lot bigger than most folks use where about 600mm would be more common.

It's a bit hard to visualise your room, but I have this habit of walking into an audio room and immediately seeing all the spots you could put bass traps. It sounds like you have a lot of "free bass traps" as your room has some lossy elements. Less work to get good bass, but more neighbour issues! So you have a cathedral ceiling? What about the lower corners? Could you run some along the length? Bulkheads that a lot of guys use could make good bass traps.

When I first tried bass traps, I measured things like opening doors and windows. Surprisingly it made little difference - I could measure it but not hear it.

Another interesting thing is that a couch moved out slightly from a wall acts as a bass trap. Moving it out moves the bottom corner of effectiveness down. You can think of it as a trap that takes care of the floor the wall corner. Remember at least 20 corners in a room!

I think it might act as one big membrane bass trap and it certainly vibrates in some scenes during movies!
I'd think of it as a leak. As a membrane trap it would not be very effective because they are pressure mode and need to sit right at a boundary to work.

I was thinking one 100mm trap each side of my TV behind the main speakers.
That would be a membrane trap, like the ones on Ethan Winers old site. I believe those are much less effective as they are narrow band traps with a centre frequency of about 90 Hz. Handy in that they are unobtrusive, but fairly limited. I plan to add some as well, but I'd consider them "bonus traps." You'll find that Ethan himself pretty much suggests that people put in the broadband traps, as many as people can fit, and no longer strongly recommends the membrane traps. A typical room is actually like one big membrane trap, but generally not a well designed one and also one in which it works only over a narrow range. They need to be tuned at different points to extend their range. There is a good BBC paper online about modular membrane traps where you can see their range. Ethan recommends 6" broadband with a 6" air gap over a membrane if you can allow the extra space or 4" membrane if that's as big as it gets.
 

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these are my favorite looking DIY subs i have seen yet. i would really love to build a couple myself as i think they are good looking enough to get past SWMBO!!

is anyone able to pen up some cut sheets??? i have tried using sketch up but i cant figure it out.
Try a free program like Cutlist. It should be able to put together what you need, if you have the rough dimensions.
 

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Discussion Starter #99
My dimensions are 53x53x46 (HxWxD) in cm. Then add 2-3cm for the curved top. The base plate is simply 22mm MDF cut slanted. Also the corners are also cut in 45 degree angles. This hides assembly points as well.

Internal volume, minus bracing, is 90 liters in mine.
 
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