Looking for Opinions on Setup using 4 Sealed Mach 5 FTW 21" Sub Woofers

[lovinthehd]

With all due respect, I dont think you have read all my posts.

I am not putting all 4 subs in 1 spot. All 4 boxes will be in different spots. 2 across the front of the room and the other 2 behind the listending area(Couch). I may move them around a bit once setup, but will see how it sounds first

The modeling has nothing to do with where I am placing the subs. I modeled one to see the SPL graph and then the way winisd works I had to muliply the cubic foot for the box by 4 to 25 cubic feet to get a proper SPL graph for 4 subs so I could see the output of 4 subs vs 1.

To answer your other questionabout the CVR amp, I had seen a youtube video of a couple guys putting that amp on an amp dyno and it was bang on to what it was rated for. I wll try and find a link to share to that as it was a while ago I seen it. If you read up on CVR amps, they do not dissapoint and are the best bang for your buck right now.

I am also not plugging it in to my wall socket, as Im sure, I would be tripping the 15 amp breaker. The amp will be located in another room right beside my hydro panel so I dont have to hear the noisy fans during quiet parts of the movie.

Im going to wire it directly into the hydro panel and feed it 220 volts and use a double 30 amp breaker so it will have plenty of juice.

Yes, I have read all the posts. That's why I said don't model the sub as if it is in one box in one location, that will yield different results than four single boxes, especially as placed throughout a room. I get what you're trying for, just saying that's just not going to get you there.

CVR amp of that output tested was at one or four channels driven at same time or what?

 

[Allen Vos]

Yes, I have read all the posts. That's why I said don't model the sub as if it is in one box in one location, that will yield different results than four single boxes, especially as placed throughout a room. I get what you're trying for, just saying that's just not going to get you there.

CVR amp of that output tested was at one or four channels driven at same time or what?

Of course. I know the software is not meant for that, but I only wanted to see the SPL charts for 1 vs 4 is all.

I was only moddelling 1 because of what TLS had said , so I wanted to make sure and try modelling just 1 to make sure that sub was suitable in a sealed box.

I do remember the amp test and it was with all 4 channels being driven

I had looked into some other amps, the berringer NX6000 and a Sinbosen.

The berringer failed miserbly trying to drive a sealed sub at low frequencies and the sinbosen was only putting out about 75% of what it was advertised.

Everyone seems to love and rave about the CVR amps in the DIY sub builds.

I could go with a quality north american made rack amp, but they are pricey.

 

[lovinthehd]

Of course. I know the software is not meant for that, but I only wanted to see the SPL charts for 1 vs 4 is all.

I was only moddelling 1 because of what TLS had said , so I wanted to make sure and try modelling just 1 to make sure that sub was suitable in a sealed box.

I do remember the amp test and it was with all 4 channels being driven

I had looked into some other amps, the berringer NX6000 and a Sinbosen.

The berringer failed miserbly trying to drive a sealed sub at low frequencies and the sinbosen was only putting out about 75% of what it was advertised.

Everyone seems to love and rave about the CVR amps in the DIY sub builds.

I could go with a quality north american made rack amp, but they are pricey.

Interesting, just haven't heard about CVR and if you can, would appreciate some links. Haven't dwelled on the avsforum diy board for a long while, built most of my subs 10 years ago now. In any case, I'd still rather run multiple amps Never heard of Sinbosen. Behringer sure, and have not used one of those due sloppy specs as a primary reason, but they bench test reasonably well (but not to marketing spec).

75% of an amp's output in what way? How is the percentage determined? Just not a good way to compare amps (i.e. via "percentage").

 

[Allen Vos]

Interesting, just haven't heard about CVR and if you can, would appreciate some links. Haven't dwelled on the avsforum diy board for a long while, built most of my subs 10 years ago now. In any case, I'd still rather run multiple amps Never heard of Sinbosen. Behringer sure, and have not used one of those due sloppy specs as a primary reason, but they bench test reasonably well (but not to marketing spec).

75% of an amp's output in what way? How is the percentage determined? Just not a good way to compare amps (i.e. via "percentage").

I will do my best to find some links for you. I can definetly post some links to CVR, sinbosen so you can have some more info on these.

I remeber with the berrringer amp, it was rated at 1200 watts RMS at a 4 ohm load and when pushed to 1200 watts at 25 HZ in a sealed application it fell hard and could only put about 600 watts of output .

the 75% output was just that. The amp could only produce 75 % of its rated output when loaded to low frequencies. For example, if the amp was rated at 1000 watts it would only push 750

I have a busy weekend but let me see if I book marked those CVR amp dyno videos and I will post them if I can find them

 

[lovinthehd]

the 75% output was just that. The amp could only produce 75 % of its rated output when loaded to low frequencies. For example, if the amp was rated at 1000 watts it would only push 750

Thanks, get back to me with the links you can find, I'd like that. No rush.

OTOH this is a good example of why a percentage isn't the best expression here. To gain a mere 3db SPL (a small increase) you'd need to go from 750w to 1500w. 750w to 1000w is a mere 1 dB (almost indistinguishable). Many amps come with "enthusiastic" specs from marketing....why we adore sites like Audioholics, ASR and Erin's for actual measurements. Even eq will eat up your amp's power advantages with boosting....

 

[Allen Vos]

I know it was mentioned about the sub over extending at low frequencies and that I had to be careful where I set my low pass frequency cut off at.

I have been playing with WINISD and have a much better understanding of it.

I have entered in all the MACH 5 FTW-21" driver specs.

The box is sealed at 6.2 cubic feet and I set it at 1200 watts as that is the max I will be putting to eash sub.

I have included the "Cone Excursion" graph and this is the conclusion I have come up with.

I have 23mm of cone travel at 5HZ
I have just over 25mm of cone travel at 4HZ
I have just over 29mm of cone travel at 3HZ

So, I feel it's a pretty safe bet to set my cutoff in my Mini DSP at 5HZ for these subs.

I am also planing on adding poly fill inside the box as well.

I know the poly fill makes the box act like a larger one, but I was wondering if adding poly fill would affect the cone travel(XMAX)?

Im guessing no, but it does not hurt to ask

Anyone care to Chyme in on this?

 

[TLS Guy]

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I know it was mentioned about the sub over extending at low frequencies and that I had to be careful where I set my low pass frequency cut off at.

I have been playing with WINISD and have a much better understanding of it.

I have entered in all the MACH 5 FTW-21" driver specs.

The box is sealed at 6.2 cubic feet and I set it at 1200 watts as that is the max I will be putting to eash sub.

I have included the "Cone Excursion" graph and this is the conclusion I have come up with.

I have 23mm of cone travel at 5HZ
I have just over 25mm of cone travel at 4HZ
I have just over 29mm of cone travel at 3HZ

So, I feel it's a pretty safe bet to set my cutoff in my Mini DSP at 5HZ for these subs.

I am also planing on adding poly fill inside the box as well.

I know the poly fill makes the box act like a larger one, but I was wondering if adding poly fill would affect the cone travel(XMAX)?

Im guessing no, but it does not hurt to ask

Anyone care to Chyme in on this?

No, it won't but sealed subs need filling with poly fill, but don't compress it.