24'' Sealed Mal-X Modification Ideas

**Mike P.** · **07-09-09, 11:22 PM**

You should be getting 115 db at 20 hz with room gain with 1500 watts. Cone excursion isn't reached until 11 hz. Either there is a problem with the sub or amp, or you have a room interaction problem causing cancellation at the lower frequencies.

Your next step should be using REW to see what the response looks like. That should give us the answers we need.

**NateTTU** · **07-09-09, 11:30 PM**

Quote:

Mike P. wrote:

...Either there is a problem with the sub or amp, or you have a room interaction problem causing cancellation at the lower frequencies.

Your next step should be using REW to see what the response looks like. That should give us the answers we need.

Even if I have a room cancellation issue, wouldn't my amp be unable to drive the sealed Mal-X to the point of causing these clanking noises?

Don't I need a sound card that has a RCA input in order to use REW along with the RS meter?

I had scheduled a pickup tomorrow of that other sub and amp. I'm wondering if I should go ahead and pick it up to see if it gives me a better response. However, whether it does or not it may mean I'm stuck with an extra sub and amp that seems to me I won't be needing.

**Mike P.** · **07-09-09, 11:55 PM**

If you're running the amp bridged into a 4 ohm load you can over drive the sub. With 2000 watts you're at Xmax at 25 hz.

$30 should get you an external sound card with the required inputs.

For $500 I would personally get the sub and amp. It would help with the overall SPL you want and take some pressure off the one you have. Just my opinion. If you do decide to get it, you'll have a first hand comparison between the two subs. It would be interesting to see if it performs the same way yours is performing now.

**NateTTU** · **07-10-09, 01:43 PM**

My design goal is to have clean ouput of 110dB from 15Hz and up. I would like to not have to be a full output so I wouldn't hurt the sub or amp. Ideally it would be at a level that the sub and amp could run at for hours at a time without any problem.

From my measurements, unless something is wrong, even if I get the added 6dB from buying another driver it won't get me that level I'm loooking for. Do you think it would be worth trying to get 2 Mal-Xs in an IB setup?

**wadesi** · **07-10-09, 02:31 PM**

I would suggest investing in some ear plugs while taking those measurments 3 ft away from the sub...

**NateTTU** · **07-10-09, 05:21 PM**

I guess so. The duration of these is extremely short. Probably only 3-4 seconds long. Just enough to get a reading so I don't think its too bad.

**Mike P.** · **07-12-09, 07:33 PM**

I'm not sure if this applies to all EP2500's but some people have reported the 30 hz HPF switch on the back is reversed. Although it says Left/On and Right/Off on the amp, it is really off in the left position. What position do you have it set to?

**NateTTU** · **07-13-09, 08:14 PM**

I attached a picture of the mode switches on the EP2500 and I think it may not be clear so here are the settings:
1 L
2 L
3 R
4 L
5 L
6 R
7 R
8 R
9 L
10 L

I also had the quick chance to run some more tests and here are the results:

Frequency:Actual Measurement:Corrected Value
25Hz:106dB:112.5dB
20Hz:99dB:108dB
15Hz:96dB:109.5dB

These measurements are up to where I believe the sub begins to complain. It doesn't clank and I had it at 15Hz up to 101 (114.5dB) without hearing the same clanking as my other driver, but I really didn't feel comfortable playing it at these levels so I just backed it down to where I think it began to complain. The best way I would choose to describe it is best shown on this video:

You Tube

I would say I took it up to the point at 20secs to 35secs in the video. I would say that my other driver was taken to the 35second mark while this one wasn't quite there, but pretty much.

Thanks,
Nate

**Mike P.** · **07-14-09, 02:14 PM**

It appears you have the #3 and #8 switches correct, as the "On" is really the "Off" position for the low cut filters.

**Kevin Haskins** · **07-14-09, 02:24 PM**

I don't deal with spl levels simply because there are too many variables in how the measurement is taken for them to be meaningful case to case. The only way they are meaningful, is if the measurement process is tightly controlled and that just doesn't happen without strict controls.

Most people don't understand enough about the measurements to understand how much they can vary with distance, room, and measurement method. If I say something on a public forum about how a Maelstrom should give 110dB at a given frequency, then anyone who doesn't measure that, gets excited about something being wrong with the device. They may be measuring in a room null, or they may be measuring at a different distance, or the amp may not have the gumption to provide enough power, or the measurement may be taken wrong. It just creates all kinds of problems for me with customer support so I avoid making any absolute statements about what SPL you are going to reach in a given configuration.

My advice on a practical standpoint, is that if one device is not enough, you really only can keep adding devices until you reach a point of having enough output for your needs. If you listen at high levels and you find one Maelstrom is finding it's limits, then add more. It is as simple as that. In sealed alignments there isn't much hand waiving you can do to change their output. It is simply a matter of physical capability of the device down low and once you reach the limits, there isn't any magic to be performed to get more output. You either increase the size of the cone (move up to a 21"), increase the stroke (which increases power required and cost of the driver) or both. Any way you slice it, your looking at more money. You can do things like move the sub into a corner which is free. Keep in mind the room has a huge impact on how much output you are going to get at the listening location. That is part of the reason I cannot make absolute statements about how much sub is enough. Every room is different and every listener plays back different program material at different levels.

Kevin Haskins
Exodus Audio

**NateTTU** · **07-14-09, 07:15 PM**

Thats some sound advice Kevin. I've decided that a 2nd Mal-X certainly can't hurt and I know 2 sealed subs in a room could help out a lot in the way my room handles bass. The only reason I posted my second set of measurements was because I would have thought my 1st and 2nd Mal-X should perform the same. It may be my fault in that I wasn't clear that I now own 2 of these great drivers. The tests may have not been perfect, but I tried my best. I used the 2nd driver in the same sealed enclosure, simply swapped drivers, powered it with the same amp, made sure all settings on my amp and processor were the same, measured them in the same location in the same room, and made sure the db meter was in the same location as the 1st test.

The last thing I want is to watch a movie and have one of my subs start clanking on me while the other one seems fine. I should say that I don't watch movies very loud as my statements are xmax limited at 110dB so I definately keep the "peaks" of the movies underneath this level. Looking at the Radio Shack meter I can say my normal viewing listening level is around 80dB with small peaks at 105dB. During normal playback everything is usually fine, its just in those rare cases in a movie where an explosion happens I don't want to be hearing anymore of the clanking sound.

**Kevin Haskins** · **07-14-09, 07:34 PM**

Quote:

NateTTU wrote:

Thats some sound advice Kevin. I've decided that a 2nd Mal-X certainly can't hurt and I know 2 sealed subs in a room could help out a lot in the way my room handles bass. The only reason I posted my second set of measurements was because I would have thought my 1st and 2nd Mal-X should perform the same. It may be my fault in that I wasn't clear that I now own 2 of these great drivers. The tests may have not been perfect, but I tried my best. I used the 2nd driver in the same sealed enclosure, simply swapped drivers, powered it with the same amp, made sure all settings on my amp and processor were the same, measured them in the same location in the same room, and made sure the db meter was in the same location as the 1st test.

The last thing I want is to watch a movie and have one of my subs start clanking on me while the other one seems fine. I should say that I don't watch movies very loud as my statements are xmax limited at 110dB so I definately keep the "peaks" of the movies underneath this level. Looking at the Radio Shack meter I can say my normal viewing listening level is around 80dB with small peaks at 105dB. During normal playback everything is usually fine, its just in those rare cases in a movie where an explosion happens I don't want to be hearing anymore of the clanking sound.

You may have an issue with a driver if that is the case. Run it in free air with a sine wave. You can download test signals off the web and burn them on a CD. You have to keep the driver off the ground, with clearance for the pole vent but if you have clanking, that is not a noise the driver should make. Run it in free-air and it quickly becomes evident if you have a problem with the driver. Since you have two drivers, it should be easy to compare. There is some normal variation but you get something that radically differs in free-air, then you probably have an issue with the driver.

That clanking in the video is the sawhorses rattling at 30s. The video is meant to show people what is normal in terms of self-noise as you reach the limits. If you are seeing something radically different then there is a problem.

Kevin Haskins
Exodus Audio

**NateTTU** · **07-18-09, 02:29 PM**

Here is a youtube video of the clanking noise. I realize at some point the driver will reach its limits, but this is the noise I heard in the sealed configuation during some movie playback and during the manual frequency tests I did last week. The "new" driver does not give me the same problem as this one during the same tests and movie clips. The level of the tests tones is recorded pretty low so thats why I had to turn up the LMC-1 relatively high.

The flashing yellow lights on the amp is just the signal lights and the red clip lights have never come on.

Sorry about the poor video quality, I guess the camera we have isn't very good at this. Let me know what you think.

You Tube

Just FYI here is the measurement on my old vs new driver at this frequency:

Frequency:Actual Measurement:Corrected Value
25Hz:106dB:112.5dB new
25Hz:103dB:109.5dB old

I stopped going higher on my new driver simply because I found it pretty uncomfortably loud and just didn't feel to comfortable taking it up any higher.

**Kevin Haskins** · **07-20-09, 07:24 PM**

I replied to your PM but it sounds like something is wrong with that driver. It is difficult to diagnose anything from a video & sound clip. I'd have to have the driver to make any real diagnosis.

Send it back and I'll take a look. If there is something loose or if the former is rubbing, that is a warranty item.

Kevin

**Warpdrv** · **07-20-09, 07:53 PM**

Send it back Nate, Kevin will take care of you, he stands behind his products....

He's a good honest business man, and has stood behind me.... If there is something wrong with the driver he'll replace it. These are man made products, nothing is perfect all the time.

**NateTTU** · **07-20-09, 10:39 PM**

Quote:

Kevin Haskins wrote:

I replied to your PM but it sounds like something is wrong with that driver. It is difficult to diagnose anything from a video & sound clip. I'd have to have the driver to make any real diagnosis.

Send it back and I'll take a look. If there is something loose or if the former is rubbing, that is a warranty item.

Kevin

Kevin,

I will run another test on it tomorrow and take a very close look at that area. Thanks.

Quote:

Warpdrv wrote:

Send it back Nate, Kevin will take care of you, he stands behind his products....

He's a good honest business man, and has stood behind me.... If there is something wrong with the driver he'll replace it. These are man made products, nothing is perfect all the time.

Warp,

I agree, I'm not at all worried about my situation as I know Kevin will take care of it. I just want to make sure I'm taking every action I can to make sure its a driver defect and not my own error.

**NateTTU** · **08-13-09, 10:35 PM**

I'm thinking once I get back my sub from Kevin that I will try to use a 22'' cube instead of the 24''. Its not too big of a change, but its enough to fit better into the front of my room and still allow cables to be routed around them.

Could anyone help me by modeling up the response of two 24'' cube (~6^3) enclosures vs. two 22" cube (~4.5^5) so I can find out how it will affect the overall frequency response? I would like to know how many db I would lose down low by doing this. If someone could provide me with a little help with the WinISD program I might be able to do it myself, but I've never really messed with it before.

Thanks,
Nate

**Mike P.** · **08-13-09, 11:17 PM**

Which sub, Gen1 or Gen2?

**NateTTU** · **08-14-09, 01:29 AM**

Quote:

Mike P. wrote:

Which sub, Gen1 or Gen2?

I believe they are both Gen 1, wasn't Gen 2 just released a month or so ago? If so they are definately Gen 1 drivers.

**Mike P.** · **08-14-09, 01:53 AM**

With 1500 watts input the difference is less than 1.5 db at 20 hz.

**NateTTU** · **09-02-09, 01:21 PM**

I haven't updated this thread recently so here is my current status:

I sent the driver to Kevin for testing and it turns out that my Mal-X had a severe rub. I just received a new replacement driver last night and it looks to be the Gen II driver. I'm very happy with the way Kevin treated me and that he sent me a new replacement free of charge.

Now, with that said, I do have a couple of question. My current setup is a Gen I driver in one of Dan's 24'' Easy Cube designs driver by a single EP2500. I was planning on building a second enclosure, same 24'' cube, and place this Gen II driver powered with a Tapco J2500. Right now I know I have to set the gain a littler higher on the Tapco to receive the same output as the Behringer, but other than that is there going to be any major differences I should worry about? I'm just wondering if I need to sell either the driver and/or amp to have the same amp/driver combo in both locations.

**Mike P.** · **09-02-09, 01:48 PM**

What's the net volume and tuning of the Dan Cube?

**Kevin Haskins** · **09-02-09, 02:39 PM**

Quote:

NateTTU wrote:

I haven't updated this thread recently so here is my current status:

I sent the driver to Kevin for testing and it turns out that my Mal-X had a severe rub. I just received a new replacement driver last night and it looks to be the Gen II driver. I'm very happy with the way Kevin treated me and that he sent me a new replacement free of charge.

Now, with that said, I do have a couple of question. My current setup is a Gen I driver in one of Dan's 24'' Easy Cube designs driver by a single EP2500. I was planning on building a second enclosure, same 24'' cube, and place this Gen II driver powered with a Tapco J2500. Right now I know I have to set the gain a littler higher on the Tapco to receive the same output as the Behringer, but other than that is there going to be any major differences I should worry about? I'm just wondering if I need to sell either the driver and/or amp to have the same amp/driver combo in both locations.

Your room contribution and change of location will probably swamp any differences. About the only way to know for certain is to build it and try. While the parameters changed, they are not as significant as you would think. I wouldn't recommend spending the money to update both of them to be the same because the drivers are not really that different. The coil is the main change.

Kevin Haskins
Exodus Audio

**NateTTU** · **09-06-09, 02:22 PM**

I don't know the exact tune of Dan's 24'' cube.

I may go ahead and give it a shot, but I'm pretty about most things so even though I may not hear anything I just may end up swapping out a driver and amp so everything can be the same. Since my room is very square and symmetrical I figure any differnces in the driver/amp combo would be pretty apparent.

**NateTTU** · **10-17-09, 04:09 PM**

Nevermind.

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