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

[Allen Vos]

Hello Everyone.

Just a quick introduction. My name is Allen and I live in Ontario, Canada.

My system consists of this

-Anthem MRX1140 receiver
-Paradigm 8000F front speakers
-paradigm premier c600 center channel
-2, paradigm X12 Sub woofers
-paradigm monitor 7 V5 side speakers
-paradigm monitor 11 rear speakers
-4, paradigm PR80 in ceiling atmos speakers

The room is 27 feet long and averages 15-20 feet in width with a 7.5 foot ceiling and comes in at just short of 3600 cubic feet, with the listening position in the center of the room.

I mainly use this as a home theater setup(70%) but also listen to music(30%), so I do like a wide variety of bass.

Low frequencies down to 10-15 HZ are important to me, but so is the mid bass punch from 30 HZ to 80 HZ

Obviously I am not getting much mid bass punch with 2 X12's in a huge space and I have to over drive the X12's in movies and the bass becomes muddy at low frequencies.

So with some research and some products being highly reccomended, I decided to purchase 4 of the Mach 5 Audio, FTW-21" subs as I have heard very good things about them

They will be going into 4 seperate sealed boxes, 6.5 cubic feet and two placed across the front of the room and the other two directly behind the listening position.

The purpose of using 4 is becasuse I want to hit low frequencies for movie watching while still having good output and want to have massive mid bass punch.

Basically I want to cover 10-15HZ all the way up to 80 HZ(sub cross over) with massive clean output and not have to deal with the "muddy" bass of ported boxes.

I will be using a CVR D-1004 rack mounted amplifier that outputs 1700 RMS watts at 4 ohms x 4 channels

I will be using a Mini DSP FLex HTx to seperate all the sub signals, and also because I need to convert an unbalanced signal to a balanced(XLR) signal with no signal loss.



I came over here from the AVS forums and just wanted to get opinions/tips on this setup and possibly any reccomendations for changes moving forward

Keep in mind the 4, FTW-21" subs are already ordered, paid for, so I am at least committed to these.

Cheers

Allen

 

[TLS Guy]

Hello Everyone.

Just a quick introduction. My name is Allen and I live in Ontario, Canada.

My system consists of this

-Anthem MRX1140 receiver
-Paradigm 8000F front speakers
-paradigm premier c600 center channel
-2, paradigm X12 Sub woofers
-paradigm monitor 7 V5 side speakers
-paradigm monitor 11 rear speakers
-4, paradigm PR80 in ceiling atmos speakers

The room is 27 feet long and averages 15-20 feet in width with a 7.5 foot ceiling and comes in at just short of 3600 cubic feet, with the listening position in the center of the room.

I mainly use this as a home theater setup(70%) but also listen to music(30%), so I do like a wide variety of bass.

Low frequencies down to 10-15 HZ are important to me, but so is the mid bass punch from 30 HZ to 80 HZ

Obviously I am not getting much mid bass punch with 2 X12's in a huge space and I have to over drive the X12's in movies and the bass becomes muddy at low frequencies.

So with some research and some products being highly reccomended, I decided to purchase 4 of the Mach 5 Audio, FTW-21" subs as I have heard very good things about them

They will be going into 4 seperate sealed boxes, 6.5 cubic feet and two placed across the front of the room and the other two directly behind the listening position.

The purpose of using 4 is becasuse I want to hit low frequencies for movie watching while still having good output and want to have massive mid bass punch.

Basically I want to cover 10-15HZ all the way up to 80 HZ(sub cross over) with massive clean output and not have to deal with the "muddy" bass of ported boxes.

I will be using a CVR D-1004 rack mounted amplifier that outputs 1700 RMS watts at 4 ohms x 4 channels

I will be using a Mini DSP FLex HTx to seperate all the sub signals, and also because I need to convert an unbalanced signal to a balanced(XLR) signal with no signal loss.



I came over here from the AVS forums and just wanted to get opinions/tips on this setup and possibly any reccomendations for changes moving forward

Keep in mind the 4, FTW-21" subs are already ordered, paid for, so I am at least committed to these.

Cheers

Allen

My question would be this. Have you modeled the driver in the box? If not, this will be an incompetent design and a total disaster.

 

[ski2xblack]

I'll second the good Doc's question, particularly given that driver is more appropriate for reflex loading as opposed to sealed. A correctly done ported box will NOT sound "muddy", that's a misconception.

 

[Allen Vos]

My question would be this. Have you modeled the driver in the box? If not, this will be an incompetent design and a total disaster.

That sounds a little harsh, lol. Could you explain why you think this will be an incompetant design?

Sorry, but when you say "Modeled the driver" in the box, could you explain that to me?

I am getting the boxes custom built and they will be 6 cubic feet accounting for bracing and what space the sub takes up.

If you have some different reccomendations, I would love to hear them?

If I have to be honest I was initially going to get a pair of the Tone winner SW-D9000 subwoofers, but they are ported and I couldnt find enough information on them and was highly reccomended to go the 4 sealed FTW-21's

 

[Allen Vos]

I'll second the good Doc's question, particularly given that driver is more appropriate for reflex loading as opposed to sealed. A correctly done ported box will NOT sound "muddy", that's a misconception.

Im not here to dispute ported vs sealed, however I will say this. Ive had ported my entire life and in all honesty I want to get away from ported. in my experince, anything ported always has massive output around the ports tuning frequency, however, I have yet to hear a ported box that sound loud and clean.

I prefer the sound of a sealed sub and in my opinion its a cleaner sound.

However as soon as you go sealed, you require a lot more power to drive them down in the 15-30hz area, which is why I am using 4 get the output higher to match the output of 2 large ported boxes.

Also when using 4 sealed subs, the output from 30-80 hz will be massive and put the ported boxes to shame.

Besides, if i went with a ported box for the FTW-21 sub, it would be massive, like the size of a refridgerator lol

 

[ski2xblack]

T/S parameters dictate appropriate cabs, whether sealed or ported. This must be modeled. (TLS has been known to model cabs for specific drivers for folks here, with positively glowing reviews, maybe he'll help you as well.)

I may have been mistaken about your drivers being more appropriate for reflex cabs. TLS can answer that question as well. Here are the T/S parameters:

Parameter	Value	Unit
Fs	22	Hz
Re	3.1	Ohms
Le	1.03	mH
L2	0.985	mH
R2	40.3	Ohms
Qes	0.47
Qms	5.24
Qts	0.43
Cms	0.152	mm/N
Rms	9.25	kg/s
Mms	343.3	grams
BL	17.77	Tm
VAS	517.6	L
Sd	1555.3	cm²
Lp	96.8	dB (2.83V/1m)

 

[TLS Guy]

My question would be this. Have you modeled the driver in the box? If not, this will be an incompetent design and a total disaster.

I have found the T/S parameters for that driver. FS is 22 Hz . So the lower frequency will be a little above that. In sealed configuration you need to add 12db/octave boost below F3, which in sealed box will be an octave or so above 22 Hz. Then you need to high pass a little above x-max to prevent driver destruction. I will model this driver in time. At the moment I am in the surgical waiting area as my wife is having a total knee replacement. At the moment you are proceeding in a manner that will not do what you want and be disaster.

 

[TLS Guy]

That sounds a little harsh, lol. Could you explain why you think this will be an incompetant design?

Sorry, but when you say "Modeled the driver" in the box, could you explain that to me?

I am getting the boxes custom built and they will be 6 cubic feet accounting for bracing and what space the sub takes up.

If you have some different reccomendations, I would love to hear them?

If I have to be honest I was initially going to get a pair of the Tone winner SW-D9000 subwoofers, but they are ported and I couldnt find enough information on them and was highly reccomended to go the 4 sealed FTW-21's

You have well and truly “put the cart before the horse”. All speakers sub, or otherwise, are founded on precise physical principles, with mathematics at its foundation. Your current plan has zero chance of producing a good useable sub. I fear you have already thrown a ton of money down the drain.

 

[Allen Vos]

You have well and truly “put the cart before the horse”. All speakers sub, or otherwise, are founded on precise physical principles, with mathematics at its foundation. Your current plan has zero chance of producing a good useable sub. I fear you have already thrown a ton of money down the drain.

A lot of this stuff is over my head, however I dont have an issue researching this and using Winisd to model the subs with the specs for the sub.

I do find your responce rather harsh as I have personally heard 4 FTW21's in the same sealed boxes I am having built and they sound absolutley incredible. Much better, cleaner bass than the 2 x12's I have.

So with all due respect, I am having trouble with your responce as many guys on the AVS Forums love these subs and have nothing but good things to say about them

Im always open to critique or critisisim, however you are the first guy I have run into that thinks this is a bad idea

Keep in mind there will be 4 of these subs, not just one, so its easier on the subs.

I dont neccesarily need to go below 22 HZ either as I dont think my X12's are hitting that either.

Anyways, Ive download WINISD and will play around and try to model these.

 

[Allen Vos]

You have well and truly “put the cart before the horse”. All speakers sub, or otherwise, are founded on precise physical principles, with mathematics at its foundation. Your current plan has zero chance of producing a good useable sub. I fear you have already thrown a ton of money down the drain.

So let me ask you a different way.

You do seem knowlegable on this stuff.

Lets say, hypothetically I havent purchased any subs.

What would your reccomendation be for subs , boxes to do 4 sealed boxes in my listening area?

I have no issue learning a few things or taking advice either. Just didnt expect to have this idea completley trashed, when its a big hit elsewhere

 

[lovinthehd]

Did any of the guys on AVS model this driver/box combo? I'd be curious how your friend's four existing subs measure, did he? I think you're off on the sealed/ported thing, altho just because a sub is ported doesn't mean its the right design either....

 

[Allen Vos]

Here is my first attempt at WIN ISD. I put as much information as I had and set the imput at 600 watts, half of what the sub is capable of. I went with a 6.2 cubic foot sealed box. This is a really nice SPL graph on this sub and this is exactly how I was told the sub would perform.

94 DB at 10 HZ
104 DB at 20 HZ

I am not 100% certain I did this properly but I did my best to get it as accurate as I could

 

[Allen Vos]

Here is a model with 4 FTW-21 subs. I obviously changed the driver to 4 , but had to multiply the box size by 4 to 25 cubic feet before the numbers looked right. Im not sure if this is the right way to do it but you can see at 100 db of output at 10HZ and 110 DB at 20 hz which is roughly 6 DB of overall increase , which makes total sense having the extra 3 drivers.

Again not sure if I did this right, but this has to be awfully close.

 

[lovinthehd]

Here is a model with 4 FTW-21 subs. I obviously changed the driver to 4 , but had to multiply the box size by 4 to 25 cubic feet before the numbers looked right. Im not sure if this is the right way to do it but you can see at 100 db of output at 10HZ and 110 DB at 20 hz which is roughly 6 DB of overall increase , which makes total sense having the extra 3 drivers.

Again not sure if I did this right, but this has to be awfully close.

Might make sense for a single box....you plan on stacking them in one spot?

 

[Allen Vos]

Did any of the guys on AVS model this driver/box combo? I'd be curious how your friend's four existing subs measure, did he? I think you're off on the sealed/ported thing, altho just because a sub is ported doesn't mean its the right design either....

TBH I dont know if anyone modeled the FTW 21 subwoofer. I know it sounded really FN awesome though.
Im sure you could build a ported box for it , but it would be way to big.

Its been my expereince that ported subs are muddy sounding near their tuning port frequency.

Ive heard many ported subs do this. Its just not the kind of bass Im after. I really am a fan of sealed subs, but in order to hit the low frequencies like the ported ones, you need more sealed subs and you need to drive them with a lot of power.

Sorry but thats my preference, and Ill take this setup over ported anyday, despite the extra costs.

It just sounds cleaner.

I got away from ported in my car as well and doubled the subs and the amps in the car and it plays hard, loud and clean.

Of course thats just my preference and some people like the ported sound better.

Just not me lol

 

[Allen Vos]

Might make sense for a single box....you plan on stacking them in one spot?

No I am going to put 2 right at the front of the room on either side of the screen and 2 more right behind the listening area and use the mini dsp flex htx to set the delays and stuff

With 4 subs in the room it should eliminate any bass nulls

 

[lovinthehd]

m

With 4 subs in the room it should eliminate any bass nulls

It'll help. Eliminate, nah. Have you modeled your room/positions with REW? An old adage about subs, they need to be placed where they need to be, not necessarily where you want them to be.

 

[lovinthehd]

TBH I dont know if anyone modeled the FTW 21 subwoofer. I know it sounded really FN awesome though.
Im sure you could build a ported box for it , but it would be way to big.

Its been my expereince that ported subs are muddy sounding near their tuning port frequency.

Ive heard many ported subs do this. Its just not the kind of bass Im after. I really am a fan of sealed subs, but in order to hit the low frequencies like the ported ones, you need more sealed subs and you need to drive them with a lot of power.

Sorry but thats my preference, and Ill take this setup over ported anyday, despite the extra costs.

It just sounds cleaner.

I got away from ported in my car as well and doubled the subs and the amps in the car and it plays hard, loud and clean.

Of course thats just my preference and some people like the ported sound better.

Just not me lol

Well designed DIY subs were ported? Commercial subs tend to have to make compromises. OTOH a LLT is rather large to go for what you originally proposed with the ULF stuff (which is hard to chase). I built my own boxes, and did sealed, mostly because I was a beginning woodworker. I don't find they have much magic going for them particularly, but definitely a lot smaller than the LLT for the drivers would be.

 

[Allen Vos]

It'll help. Eliminate, nah. Have you modeled your room/positions with REW? An old adage about subs, they need to be placed where they need to be, not necessarily where you want them to be.

I have not modeled the room, but It sounds like I had better learn to figure that one out too lol

I do have REW on the laptop and was going to get a umik 1 microphone as I believe I need to use REW to setup the MINI DSP Flex HTx with it.

After that is setup, I will be using the ARC room correction on my Anthem reciever to dial the room in.

I will likely set it up the way I desrcibed first and see how it sounds before I play with it and start moving the subs around.

 

[Allen Vos]

Well designed DIY subs were ported? Commercial subs tend to have to make compromises. OTOH a LLT is rather large to go for what you originally proposed with the ULF stuff (which is hard to chase). I built my own boxes, and did sealed, mostly because I was a beginning woodworker. I don't find they have much magic going for them particularly, but definitely a lot smaller than the LLT for the drivers would be.

The only ported subs I have seen , were commercial, store bought ones and they sounded ok, but just not the sound I wanted. The issue I would run into using a ported box is I dont have the room for 4 ported refridgerator size boxs lol So I am just going to do sealed and see where this takes me.

Did you look at the SPL modelling graphs for the 4 subs I posted?

How does it look to you?


Its my first attempt at sub moddeling and, It seems like a tonne of output right from 10 HZ right up to my crossover at 80hz.

This will definitley have more output than my 2 paradigm x12's