Carvin Audio TRX3903 "clone" w/Faital 3FE25 worth it?

mga2009

Member
2015-11-20 10:34 pm
Hi,

I am a big fan of the Faital 3FE25 full range speaker. I've built a couple of XRK971's 0.53x Karlsonators with these, and I am still astonished how good they sound for a 3" with foam cabinet...

A few moments ago, I found the Carvin Audio TRX3903 array system uses these very same Faital 3FE25 speakers, and I only found good reviews for the TRX3903, flat from 160hz up to 20khz, so...

Is it worth it to make an array with 9x 3FE25 each, in a sealed cabinet with similar/exact dimensions of the TRX3903? Is there any other thing to consider here?

Do you think it's one sealed cabinet or multiple sealed ones? One for each driver?

I would make the baffles with a CNC, using 15mm plywood and all the drivers would be mounted flush, and with round-overed edges.

These would be paired with 2x 15" sealed subwoofers, and there is some DSP possibilities I can arrange (MiniDSP or 3E ADAU 1701). They will be powered will be standard AVR, but I hope to eventually use an ICEpower amp.

The use will be strictly movie watching and maybe some music listening (non critical) in a small rectangular room, with carpet and sound treated with acoustic panels on front and back walls (not in ceiling), at moderate listening levels (around 80-85db)

Here is more info on the TRX3903:
https://cdn.shopify.com/s/files/1/0476/5297/files/TRx3903_data_sheet.pdf?3848715814622817784

https://cdn.shopify.com/s/files/1/0476/5297/files/TRC-A_systems_user-manual.pdf?3848715814622817784

Also, I've read most of the wesayso's "Two Towers" thread here:
https://www.diyaudio.com/forums/full-range/242171-towers-25-driver-range-line-array.html

Thanks in advance for your insights!
 
Looking at the links you provided I think I can say with confidence the cabinet is a single sealed box. At 21 lbs per cabinet nine 3FE25s weigh 11.25 lbs, more than half the cabinet weight. Also, looking at the rear, with an access panel that large I doubt there are individual compartments for each driver. My personal preference would be for individual chambers but that adds complexity and cost to the build. You would also need to calculate the individual chamber size per driver and account for the added total thickness of 8 separation panels in the cabinet. That would affect at least one of the 3 cabinet dimensions (height, width, depth) in order to maintain the proper volume.
 

mga2009

Member
2015-11-20 10:34 pm
Looking at the links you provided I think I can say with confidence the cabinet is a single sealed box. At 21 lbs per cabinet nine 3FE25s weigh 11.25 lbs, more than half the cabinet weight. Also, looking at the rear, with an access panel that large I doubt there are individual compartments for each driver. My personal preference would be for individual chambers but that adds complexity and cost to the build. You would also need to calculate the individual chamber size per driver and account for the added total thickness of 8 separation panels in the cabinet. That would affect at least one of the 3 cabinet dimensions (height, width, depth) in order to maintain the proper volume.

Thanks for your reply!

I too think it's a single sealed cabinet, which means an easier assemble.

The thing is that IDK how they get 8ohm out of an uneven number of drivers...

Waybe I can get away with only 8 drivers on each speaker?

Another thing to consider is my quite short listening position... left and right speakers are at around 1.5meters from MLP. Would this represent a problem for a full range line array?
 

perceval

Member
2014-02-21 8:17 am
Taiwan
I have built a 9-driver test column as a test before doing my 16-driver array later on.

As posted right before, if you wire any number of drivers as 2x2, 3x3,4x4,5x5, etc... in series/parallel, you will get the same impedance as a single driver.

Also as mentioned in the Carvin documentation, the horizontal spread is quite wide, but the vertical is limited to the drivers height. If your head is above or below the line of drivers, you will lose the highs very rapidly.

Another thing is comb filtering. If you plan to listen to them from 0 to 1,5m, there will be comb filtering.

The farther you are is the best. A very minimum of 3m away from the column is required to not feel the comb filtering. The cool thing is that with arrays, the sound carries much farther, with less loss than a regular single driver box.

So, as long as you can put them away from you, and keep your head in the column of drivers, it will be fun.
 

mga2009

Member
2015-11-20 10:34 pm
Sorry, I wasn’t trying to discourage you, rather I was saying that with the various choices for the driver it should be easy to arrive at a suitable combination for 9 drivers at 8 ohm. As others have chimed in, it’s even easier than that.

Thanks, yes... I understand now.

I have built a 9-driver test column as a test before doing my 16-driver array later on.

As posted right before, if you wire any number of drivers as 2x2, 3x3,4x4,5x5, etc... in series/parallel, you will get the same impedance as a single driver.

Also as mentioned in the Carvin documentation, the horizontal spread is quite wide, but the vertical is limited to the drivers height. If your head is above or below the line of drivers, you will lose the highs very rapidly.

Another thing is comb filtering. If you plan to listen to them from 0 to 1,5m, there will be comb filtering.

The farther you are is the best. A very minimum of 3m away from the column is required to not feel the comb filtering. The cool thing is that with arrays, the sound carries much farther, with less loss than a regular single driver box.

So, as long as you can put them away from you, and keep your head in the column of drivers, it will be fun.

Thanks for your reply. I don't think I can get that far away as the room is quite small. The idea is to have them right at ear/head height.

Would the comb filtered effect be reduced if I use less drivers?

Any squared number is easy to wire.. 9 drivers means 3 parallel sets of 3 in series (or vice versa) for the same overall impedance as a single driver

From the specsheet, it seems they are 3 in series and then those 3 clusters in parallel. If I use 8ohm 3FE25, that would get me 8ohm total impedance, correct?

3 in series = 24 ohm
24ohm cluster x 3 in parallel = 8ohm.
 
Would the comb filtered effect be reduced if I use less drivers?

No, unless you use one driver... ;)

Remember, that system was designed as a lightweight PA system, and it is to usually cover a big space / venue.

It is not designed to use in a small room.
If you still want to use an array of small drivers in a small room, then you could go WWMTMWW, but that means you will be using crossovers.
 
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mga2009

Member
2015-11-20 10:34 pm
No, unless you use one driver... ;)

Remember, that system was designed as a lightweight PA system, and it is to usually cover a big space / venue.

It is not designed to use in a small room.
If you still want to use an array of small drivers in a small room, then you could go WWMTMWW, but that means you will be using crossovers.

Thanks for your help!

It seems that for now... there is no array for me.

Bye!