Home Theater Forum and Systems banner

1 - 19 of 19 Posts

·
Registered
Joined
·
77 Posts
Discussion Starter #1
I have finally gathered all materials (sans MAL-X driver) to build a 24" cube (based on NEOdan's cutsheet). After reading tons of threads I am torn between sealed (my original plan) versus adding 2 of the EX-PR18 PRs to the box. Since I am ready to glue (all parts cut) I must decide. The deal that Kevin has posted on the driver + PRs looks pretty good when the MAL-X is back in stock.

Room is rather large (24 x 35 x 8) so output is important. I primarily listen to music (60%) and watch movies (30%) / concert DVDs/Bluray (10%). Musical taste is varied but I listen to a lot of 70s hard rock and traditional jazz (probably a weird combination). Volume is usually - 10 dB from reference, but occasionally will play at reference if no one else is home. For amplification I am leaning towards a Crest Audio CC2800.

Any advice would be great, I tried to model on WinISD but couldn't figure out how to model PRs.

Thanks
 

·
Registered
Joined
·
1,026 Posts
It is fairly simple, the PR version gives you more extension down to the resonant frequency of the PRs and a substantially more output. It is equal to about two of the sealed versions down @ tuning.

If you have a big room, I think it is worth going to with the PR version.

Kevin Haskins
Exodus Audio
 

·
Registered
Joined
·
77 Posts
Discussion Starter #3
Thanks for the simple explanation.

How do I calculate the required mass for each PR? I know the mass effects the tuning but do not know/understand the math required to calculate. Would like the have good bass extension - but don't want to have extreme power requirements due the the sub producing the deep bass.

What tuning would you suggest and how much mass is required on the PRs to get to that tuning? With the extra funds required for the PRs will need an inexpensive subsonic filter - any suggestions?

Thanks again for the advice. I want to build the PR-version, just need some clarifications.
 

·
Registered
Joined
·
1,026 Posts
Thanks for the simple explanation.

How do I calculate the required mass for each PR? I know the mass effects the tuning but do not know/understand the math required to calculate. Would like the have good bass extension - but don't want to have extreme power requirements due the the sub producing the deep bass.

What tuning would you suggest and how much mass is required on the PRs to get to that tuning? With the extra funds required for the PRs will need an inexpensive subsonic filter - any suggestions?

Thanks again for the advice. I want to build the PR-version, just need some clarifications.
I'd push the size up a little if you go PR. You want about 7-9 cubic feet. You are going to load it up with mass based upon the size of the enclosure but your tune will be around 17-18Hz.

With this driver, you need power. Basically, if you have a lot of stroke, running in realistic sized enclosures and designed for 1st/2nd octave, you need the power to utilize it. There is no way around it.

A lot of people talk about efficiency but for subs, it is pretty much a non-issue. It isn't a transducers efficiency that is going to determine output down low. It is determined by the box and that is a point that very few people understand. Efficiency is solely dictated by the moving mass & BL motor strength. When you increase BL, you increase efficiency but you do so at the expense of bandwidth in a given box size. Same thing with Mms, if you decrease the moving mass, you increase efficiency but once again lose bandwidth for a given box size.

So... the box ultimate determines efficiency down low in the frequency range. As a consequence, if you want lots of output, you need lots of stroke & power. Since the efficiency is set by the box and choice of bandwidth, our power needs for a given output are set in stone. If you want more output, you need more stroke and to use it, you need more power and there is nothing that anyone can do to change that relationship.

In terms of inexpensive, I'd advise the following. I'd either build it with the right parts or build something else that requires less power. Personally, I'd not build a sub without EQ & room measurement tools. It can make a significant improvement in sound quality. The SMS-1 is my standard recommendation because of flexibility and ease of use and it has a variable subsonic filter for a resonant build. The EP-2500 is less than $300 street price. Between the two of them you have < $700 invested in power, room measurement, and all the signal processing you need. If that is out of your budget, I'd aim for a less expensive sub that doesn't require the power of the Maelstrom.

Kevin Haskins
Exodus Audio
 

·
Registered
Joined
·
77 Posts
Discussion Starter #5
I'd push the size up a little if you go PR. You want about 7-9 cubic feet. You are going to load it up with mass based upon the size of the enclosure but your tune will be around 17-18Hz.
This would be difficult as I already have started construction using NeoDan's 24" sealed cube cutsheet. All materials are cut, ready for assembly.

With this driver, you need power. Basically, if you have a lot of stroke, running in realistic sized enclosures and designed for 1st/2nd octave, you need the power to utilize it. There is no way around it.
As you indicated power is relatively inexpensive, I could spend less on an amplifier (go w/ EP2500 vice Crest Audio) to free funds for other expenses of PR compared to a sealed design (low pass filter, PRs, etc).


In terms of inexpensive, I'd advise the following. I'd either build it with the right parts or build something else that requires less power. Personally, I'd not build a sub without EQ & room measurement tools. It can make a significant improvement in sound quality. The SMS-1 is my standard recommendation because of flexibility and ease of use and it has a variable subsonic filter for a resonant build. The EP-2500 is less than $300 street price. Between the two of them you have < $700 invested in power, room measurement, and all the signal processing you need. If that is out of your budget, I'd aim for a less expensive sub that doesn't require the power of the Maelstrom.

Kevin Haskins
Exodus Audio
Seems to me that to stay close to my original budget, I should stick with my original sealed plan and add an EQ/room measurement tool. Lots of people are happy with the sealed sub. I am replacing a 10-yr old Paradigm sub, so no matter how I proceed it will be a vast improvement.

Thanks again for your assistance!
 

·
Registered
Joined
·
533 Posts
Congrats on the start, the Mal-X's in a 24" sealed cube are fantastic and will really put out tons of excellent clean powerful bass.... providing that they are powered properly.

If I may make a suggestion, I have 3 of these in a very very large room, 1/3 larger then yours or better. If I were you, I would shoot for an amp larger then the ep2500, I tried using them and they kept clipping everytime I would get close to the output I wanted from them. It was impressed upon me that I would not benefit from larger amps, stating I would only get a touch more output from them before I smacked them to bits. Regardless I knew I was amp limited. I went out on a limb and bought 3 - Crest 8002 (4000w bridged) - overkill to be sure.... every and all problems I had were long gone, and I could be happier with this combination. The amps aren't set even close to full output but they provide me with tons more headroom and aren't struggling to power my subs....

The Mal's can handle much more power sealed - almost beg for it... You will get much more output with a bigger amp then EP2500's

Depending on how much output you are looking for, you may want to add a second Mal-X for that size room.
 

·
Registered
Joined
·
62 Posts
That is strange. Mine has great output but by the time the clip lights even flicker, I'm pushing the limits of excursion (or at least I think I am) because it starts sounding a bit distorted. I can see where a larger and/or better amp might provide a bit better attack or transient response, although the EP doesn't seem to be any slouch for that either.
 

·
Registered
Joined
·
77 Posts
Discussion Starter #10
Congrats on the start, the Mal-X's in a 24" sealed cube are fantastic and will really put out tons of excellent clean powerful bass.... providing that they are powered properly.

If I may make a suggestion, I have 3 of these in a very very large room, 1/3 larger then yours or better. If I were you, I would shoot for an amp larger then the ep2500, I tried using them and they kept clipping everytime I would get close to the output I wanted from them. It was impressed upon me that I would not benefit from larger amps, stating I would only get a touch more output from them before I smacked them to bits. Regardless I knew I was amp limited. I went out on a limb and bought 3 - Crest 8002 (4000w bridged) - overkill to be sure.... every and all problems I had were long gone, and I could be happier with this combination. The amps aren't set even close to full output but they provide me with tons more headroom and aren't struggling to power my subs....

The Mal's can handle much more power sealed - almost beg for it... You will get much more output with a bigger amp then EP2500's

Depending on how much output you are looking for, you may want to add a second Mal-X for that size room.
Thanks for the advice. I have been looking at the Crest line (CC-4000 (4000 watts bridged into 4 Ohm) or the CC-2800 (2800 w bridged)). Decided to go sealed w/ either the Reckhorn B-1 or the Elemental Design eQ.2 (I am leaning towards the ED). Started gluing the box this weekend - lesson learned is that you can NEVER have enough clamps! I am taking photos and may start a build thread when completed.
 

·
Registered
Joined
·
62 Posts
Did you check out the BFD? If so, what didn't you like about it? On the two units you mentioned, I would enjoy the ability of reaching up and twising a good old fashoined knob. On the other hand, the BFD has so many more channels, plus you can save settings...
 

·
Registered
Joined
·
533 Posts
That is strange. Mine has great output but by the time the clip lights even flicker, I'm pushing the limits of excursion (or at least I think I am) because it starts sounding a bit distorted. I can see where a larger and/or better amp might provide a bit better attack or transient response, although the EP doesn't seem to be any slouch for that either.
I'm not sure what size room you have, so maybe you are getting far more pressurization then I am, Just my room alone is 8200^3, open to pretty much the rest of the house, so I have to push it pretty hard to get the flex I am looking for, but there is no question that the amps were the limiting factor - I can't tell you how much of an improvement there was by stepping up to the much larger amps, no more farting noises from the driver as the onset of clipping... Everyones rooms and needs are different, and mine is a ******* beast to fill, but I got all I need now and no clipping....

Thanks for the advice. I have been looking at the Crest line (CC-4000 (4000 watts bridged into 4 Ohm) or the CC-2800 (2800 w bridged)). Decided to go sealed w/ either the Reckhorn B-1 or the Elemental Design eQ.2 (I am leaning towards the ED). Started gluing the box this weekend - lesson learned is that you can NEVER have enough clamps! I am taking photos and may start a build thread when completed.
If you can even find them now at all, both Ricci and I hunted down a handful of them and snatched them up, took a long time to find them - but the Crest 8002's are incredible power plants, and have some great features built in, like a ground lift switch, XLR in and out for daisy chaining amps together... I am so happy with them, I'll never have to look for amps again... Crest has some great amps, they measured fantastically, otherwise Crown CE4000's would be killer as well.... not sure if Ricci is still selling his or not - PM him...

I run the 8002s at about the 1:00 mark and can adjust gain to them via my SMS-1 - truly astonished with my setup now.... 3 x Mal-X sealed + 1 15" TC-3000 for behind the listening position... seriously scary output. :hsd:
 

·
Registered
Joined
·
533 Posts
No question about it, they are louder, I am lucky though with having the ability to remove all my amps down to the basement out of sight and ear shot... the crest amps each have dual 20mm fans and are like a turbine with them all running, which is why I relocated them. The EP2500 fan modded was barely audible in my room...

I don't think this is a subjective question at all random... every part of onse system must be taken into consideration, and that was a big play in my decision and ability to move my amps, where not everyone has that luxury....

My point was to bring to light the need or call for the Mal-X's sealed to have a good powerplant, and don't buy and amp like the EP when/if you can go and may need to go bigger...

Just hoping to help those to alleviate the pains of buying amps twice like I did....
 

·
Registered
Joined
·
1,648 Posts
I have the Crown XLS and measured the fan noise 1 foot from the back of the amp at 61db C weighting. To me the noise is not a problem.

Matt
 

·
Registered
Joined
·
2,431 Posts
/Crown CE4000's would be killer as well.... not sure if Ricci is still selling his or not - PM him...
:
Nope. I'm keeping my pair now.

Can't believe we tracked down and bought 8 of those suckers between us in the last couple of months.:spend:
 

·
Registered
Joined
·
533 Posts
Nope. I'm keeping my pair now.

Can't believe we tracked down and bought 8 of those suckers between us in the last couple of months.:spend:

Hahahah right buddy...

Can't say the last one was even really necessary, but I have grown to not care for the EP2500 much over the time I have had them....

My QSC 2500's are for sale at this point, if anyone is interested...
 

·
Registered
Joined
·
77 Posts
Discussion Starter #18
Did you check out the BFD? If so, what didn't you like about it? On the two units you mentioned, I would enjoy the ability of reaching up and twising a good old fashoined knob. On the other hand, the BFD has so many more channels, plus you can save settings...
Sorry it has taken so long to get back on the board, extensive travel for my job and honey-do lists.:dizzy:

The BFD looks to have a steep learning curve, I am looking for simple solutions. The two-band ED looks quite capable but I am concerned about the turn-on thump warned against in the manual. I don't think I need the gain of the Reckhorn, I have not seen that people have had troubles with Onkyo HT receivers friving pro amps.

I did settle on going sealed (my original plan) and completed the enclosure over the 4-day weekend.
 

·
Registered
Joined
·
2,431 Posts
Did you decide on the amp yet? CC4000 might be a good choice. I almost bought one myself to try out. As far as EQ the SMS1 seems easy to use (I don't own one). Not sure what your budget looks like.
 
1 - 19 of 19 Posts
Top