24'' Sealed Mal-X Modification Ideas

**NateTTU** · **06-21-09, 08:56 PM**

I currently have a single Mal-X in a 24'' cube powered by a single EP2500. I seem to be running out of headroom and I believe this is because of my amp. I originally thought this setup would quinch my thirst for a small 14x12 room, but unfortunately it isn't. I thought about buying a better amp for the driver, but for the price difference here are a couple of other alternatives I was thinking of going and was wanting some input on the amount of performance increase/decrease I would receive.

1) Add 2 PRs to the setup and continue to use the EP2500
2) Add a 2nd driver to the 24'' sealed cube and add another EP2500

I know 2 PRs would help in low end extension but what about headroom. Would I still be running out of power on my amp? I'm leaning a bit more towards this option as its cheaper, but of course only if it would help.

The 2nd alternative is a little bit of a stretch right now as I will definately need wife approval. I just purchased a 60'' Kuro so I'm not so sure I want to jump into another project that will cost hundreds.

Attached is a paint image showing the current layout. The sub location in red will probably be the final placement and would be able to accept any of the 2 options listed above.

Thanks.

Nate

**Mika75** · **06-22-09, 10:01 AM**

I think u need to eq some boost into the bottom end.

**Mike P.** · **06-22-09, 02:44 PM**

If you're running out of headroom with over 2000 watts then you need another sub. You don't have the 30 hz HPF engaged on the amp do you?

**Ricci** · **06-22-09, 03:46 PM**

First determine exactly what the bad noises from the sub are caused by, so you can appropriately address the problem. Either amp clipping or overexcursion. Run the material that is causing the sub problems with the mains disconnected and starting at a moderate volume, slowly increase the level until you hear distress. Note the excursion from the driver if it is over 2" p2p the driver is probably just starting to distort and you need more cone area. Also check the amp clipping indicators to ensure that you aren't clipping the amp badly. It may also be other things like an air leak around the driver, or mounting screws(I've had this happen before) or something else that develops in the enclosure at high volume.

**NateTTU** · **06-22-09, 09:15 PM**

Don't get me wrong, nothing really is wrong with my current setup. I just really like bass and I'm just looking for a little bit more. This sub really is insane, but I just want a bit more so I will never reach my limit without physically becoming ill. Thats all

I can clip my amp on some scenes right when I'm feeling its just about the right amount of output so all I'm looking for is just a slight upgrade and thats why I asked these questions. I've clipped my amp maybe a total of 3 really brief times, but I just want to make sure I have a little more headroom to avoid that in the future.

I know I'm amp limited, but unfortunately in such a small space I can't really build another sub so thats why I was looking into these other alternatives.

**Mike P.** · **06-22-09, 09:55 PM**

By adding a pair of 18" 2100 PR's from A.E. you'd gain about 2 to 3 db from 16 to 40 hz. A high pass filter would be required at 14 hz.

**Kevin Haskins** · **06-23-09, 11:05 AM**

Your right around 6 cubic feet. I'd forgo the PRs personally and get some room measurement & EQ capability. With some room measurements you can better analyze where your at before spending more money.

If you get something like the Velodyne SMS-1 you have a software adjustable subsonic filter which you will need if you decide to upgrade to the dual PR-18" approach. Get something that gives you a better idea of where your at and gives you complete control over your room curve first.

Kevin Haskins
Exodus Audio

**NateTTU** · **06-23-09, 01:19 PM**

The PR sounds like a great plan, but I think Kevin is right. Honestly, its things like this that let me know if I was to go with a PR I would definately purchase from Kevin. I like someone who is honest and not always trying to sell more to me than what I may really need. This is also the same reason why I tell everyone that comes to my house they need buy a Mal-X to make their own so i can enjoy my own.

**NateTTU** · **07-08-09, 12:26 AM**

I found a guy locally with a 24'' cube sealed Mal-X with an EP2500 for a pretty decent deal. I'm not sure how much a used driver is worth, but he tells me he never clipped anything and overall ran it pretty low since he lived in an apartment. Now I know some EQ would help and thats something I'm still thinking about trying down the road, but for probably a little more than a SMS-1 I can double my current setup. Should I go with this and hopefully this will fullfill my bass needs? It isn't every day something like these come up for sale so I'm seriously considering his offer. In any case I'm still looking for more output and I just don't think a better amp is worth the extra cost and I doubt it will buy me anymore headroom. At least, not as much as I'm looking for. Also, an EQ would help, but it would easily eat even more headroom out of my amp once I try to boost up the lower frequencies.

BTW, I asked this over at AVS, but I didn't seem to find anyone with a similiar issue. I've watched a few movies and it seems at times that the driver makes some "flapping" noises when it moves. I would say its a difficult sound to describe, but the best I can think of is playing a 15Hz test tone and I can't hear the frequency played, but I can still hear the driver moving. This sound is hidden within the actual sounds it plays during the movie so its difficult to only hear that one thing. Just curious if anyone else experienced the same thing. I doubt the driver is damaged as even though I'm looking for more headroom I very rarely ever clipped the amp, maybe 4 quick times, I'm just trying to avoid it again in the future. Plus, with more headroom I would probably run the sub a little hot during movies.

**Mike P.** · **07-08-09, 09:28 AM**

Quote:

Should I go with this and hopefully this will fulfill my bass needs?

It would go a long way in my opinion, especially if the price is right. but as Kevin stated, you should get some room measurements so you can better analyze where your at.

**vili** · **07-08-09, 11:18 AM**

Dunno how much he is charging, but if you can get an amp and the finished product at a cost savings I would go for it. That flapping sound you might here could be overexcursion and a second mael should add 6db to the total output. Assuming you don't want to just keep them pushed to their limits all the time it very well could fix your problem.

**NateTTU** · **07-08-09, 01:17 PM**

I'm not sure if price talk is allowed on the forum, but he is offering the driver, Tapco J2500 amp, and 24'' sealed enclosure for $500. I've never heard of the amp, but I was told the Tapco is a copy of the EP2500 like I have. He is about 45 mins away and I planning on picking it up on Friday. The only thing I would still need is a RCA Y splitter and a short RCA to XLR cable.

Mike,

I'm still very new at this, but would buying more subs cause any further room issues? I should be able to locate them in opposite corners in the front of the room so I'm hoping this would help alleviate some current problems. I think my room eats a lot of the bass, but I figured for this price it might be worth it just so I won't operate so close to max output with one driver.

BTW, a 6db gain would be worth it right?

**vili** · **07-08-09, 01:46 PM**

Sounds like a good deal as long as everythings in good shape. The mael-x shipped would cost just about that much new, plus the enclosure and amp for free basically. Y splitters are very cheap so no worries there.

More subs can help alleviate room problems. I currently have a 26" cube mael-x and I had a couple of nulls, but when I even hooked up my 12" bic h-100 sub on the other side of the wall, it got rid of most of them. Not to mention the extra output can almost "power" through some nulls if that makes any sense.

6db is a pretty big gain. 3db requires doubling in power of output so essentially for your one sub to do the same output as both you would essentially need 3x the amp (assuming the driver could handle the power). Most people say that 10db is equating to doubling the loudness of something, so a 6db increase is a big jump in terms of loudness.

**Mike P.** · **07-08-09, 02:00 PM**

The specs on the Tapco J2500 look good and it's almost twice the weight of a EP2500.

Two subs allow for various room placements which can help even out the low end response.

What make and model number of receiver are you presently using to power the EP2500?

**NateTTU** · **07-08-09, 07:09 PM**

Thanks for the responses.

Vili,

The EP2500 is a really good deal for the price. I realized that buying a better amp would be a benefit, but you are right that it would take more amp than the Mal-X could handle to make it really worth the upgrade. Most amps I saw were about the same price as buying this second sub/ep combo. It just didn't seem worth it to me.

Mike,

I'm currently using a LMC-1 as my processor and hopefully within a month or two will be replaced by the UMC-1. I know the UMC-1 will have some EQ ability, won't be much but it will be something. I thought about buying a different receiver, maybe one with Audyssey, but I'm not sure if I'm willing to go with a single receiver over seperates for this feature alone.

**Mike P.** · **07-08-09, 07:35 PM**

How high is the gain set on the EP2500?

**NateTTU** · **07-08-09, 10:23 PM**

I've had to adjust it every once in a while, but I think right now its set at 26.

**NateTTU** · **07-09-09, 08:34 PM**

Troubleshooting/Testing

Tonight I will try to do my best at testing my system to see what exactly I need to do to get my desired bass needs.

I have a lot yet to try and I will try to update this thread as I work, but here is what is currently happening.

I purchased an Analog RS meter after work.

I punched in Serenity on Blu-Ray and ran a scene I know was giving me some problems. I have the RS meter set to C weighting and fast response.

Without any sort of correction factor I received 104-105dB on the meter when I heard the first clank.
I ran the same scene with only the Statements and turned them from small to large on the LMC so there was no sub output and on average was measuring about 1dB greater output on the Statements and didn't have any problem. No wierd noises or clanks. Another important note is that I do note hear any "flapping" that I mentioned before with the Statements. I would assume that maybe the flapping is caused by lower frequencies that my Statements can't pick up on or just because the area of the sub is so much larger that it makes it more pronounced. Those of you who are not familiar with the Statements its just another diy design that can be found here:
http://www.geocities.com/cc00541/Statements.html
It should be said these are some pretty large and capable speakers.

Things to note:
-I don't know what the actual measurement should be without the correction factor so I will run some test tones next. This was just a preliminary test.
-I don't have REW and do not have the ability to do an actual sweep test on a computer to post. Everything will be manual.
-I have never had a large pro amp and sub combo like this before so I should say that when I hear a clank I assumed it was my amp. However, every time I have heard this both now and in the past I have never actually scene my amp clip lights ever come on.

More to come.

Any suggestions or changes I should try please let me know.

Thanks,
Nate

**Mike P.** · **07-09-09, 08:45 PM**

Run the test tones and apply the correction factor for your meter. That will get things started.

**NateTTU** · **07-09-09, 09:10 PM**

I ran a manual test tone of 25Hz to the sub. Right before any clanking noises I read 103dB on the meter so add the correction value I only got 96.5dB at the listening position. I still did not see any clip lights. I'm too scared to run this through my Statements so I'm going to stop at that. I think they have good response down into lower 30s but 20 something is too much for me.

Let me know of any further test I need to try.

EDIT: I would like to try something higher, probably 50Hz. How long should the tests run and how long should I wait between each one? 30 seconds 30 mins?

**NateTTU** · **07-09-09, 09:55 PM**

Hahahah, well I tried the 50Hz test tone.

I got up to a reading of 111dB on the meter so with the correction factor that comes to about 109dB. I have to say it was pretty loud and I liked it. However, when I tried to go up any further my breaker flipped. I thought it was pretty funny. So apparently I can't go any higher than that for right now.

**Mike P.** · **07-09-09, 10:09 PM**

Do separate test tones from 25 hz to 15 hz note the SPL, and if you hear the clanking sound at any frequency. Take the reading at 3 feet from the sub.

With separate test tones then run then only long enough to get a reading.

**NateTTU** · **07-09-09, 10:51 PM**

Ok.

Measurement is 3 Feet from sub in room. Measurement taken is at max value right before any clanking. One notch higher on the receiver causes the clanking.

I hope 5Hz increments will work.

Frequency:Actual Measurement:Corrected Value
25Hz:103dB:109.5dB
20Hz:98dB:107dB
15Hz:89dB:102.5dB (value not given so I averaged 14Hz & 16Hz values)

EDIT: Hopefully these have been corrected.

**Mike P.** · **07-09-09, 10:55 PM**

Regarding the correction file, whatever the negative number is beside the frequency, that is how much less the reading is then it is supposed to be. You add that number to the SPL reading that you get.

**NateTTU** · **07-09-09, 11:03 PM**

These should now be fixed. What do you think? Should I get another sealed sub now?

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