Adding a mid/tweet to a Faital PR400 15" box

[bass_69]

I am in the process of bulding 2 x 115 cabs based around the PR400 driver. I have put together a test box (only screwed at the moment). It is 2.8 CF tuned to 50hz. That all models well in WinISD and sounds good in testing. I am now considering the option of adding some high end to this test cab. There is not much space left on the front baffle due to where the speaker cutout was placed. I didnt consider adding drivers when I got this cutout. I am wondering what the experts on here think about adding 2 x Faital 3FE25 drivers using a 400w crossover - Crossover frequency: 2,500 Hz, 18 dB/octave HP, 12 dB/octave LP. Here is the driver specs FaitalPRO 3FE25

My goals are as follows:
- Add some high end clarity. Rather than just jack up the frequencies around the limit of the PR400 I would like the high end to cover a broader range if this makes sense. Should be smoother and generally have a better intergrated sound.

- Gain some off axis improvement in the high mids/highs. I would love to be able to crossover lower than 2.5k but that gets a whole lot more difficult and dont have the space on the baffle for bigger drivers that can handle the power.

- The high end gain must be smooth. The paper cone should sound smooth and being ferrite should break up nicer than neo ? Plan B would be to add 2 small soft dome tweeters and crossover at say 3.5k with no LPF.

My questions are:
1) Will 2 of these drivers have the power handling capability above 2.5k to match the PR400 ?
2) What impedance should these be and how would they be wired (series/Paralell) ?
3) Would you low pass the PR400 or run it full range - IE just use the crossover as a HPF for the 3FE25 ?
4) Would the 3FE25's be ok not having their own chamber within the cab ?
5) These have a 91bd efficiency. My basic understanding is that 2 should increase this by say 3db to say 94db. Is that a good match volume wise for the PR400's 99db ?

Hopefully a pic of the cab (albiet the wrong orientation) is showing the cab to date with a couple of paper cuttouts of where the mids will go)

 

[6thplanet]

They will absolutely need their own enclosures.

 

[Arjank]

My questions are:
1) Will 2 of these drivers have the power handling capability above 2.5k to match the PR400 ?
2) What impedance should these be and how would they be wired (series/Paralell) ?
3) Would you low pass the PR400 or run it full range - IE just use the crossover as a HPF for the 3FE25 ?
4) Would the 3FE25's be ok not having their own chamber within the cab ?
5) These have a 91bd efficiency. My basic understanding is that 2 should increase this by say 3db to say 94db. Is that a good match volume wise for the PR400's 99db ?

1. you mean a pair of 3FE25's per PR400? then probably yes
2. 2x 16ohms wired parallel
3. full range (keep it simple)
4. no
5. efficiency should be ok when running m as a pair, you'll definitely hear an increase in mid/highs

That said, this wouldn't be my choice. But since you already build these cabs it's probably the best option to increase the mid/highs.
The position of these two 3" drivers ain't optimal though, it will create some lobing in the horizontal plane. Since this isn't hifi it shouldn't be much of an issue.
Btw. I wouldn't go for option B, a (1") soft-dome tweeter and a 15" woofer isn't a great match.

 

[5StringPocket]

I am in the process of bulding 2 x 115 cabs based around the PR400 driver. I have put together a test box (only screwed at the moment). It is 2.8 CF tuned to 50hz. That all models well in WinISD and sounds good in testing. I am now considering the option of adding some high end to this test cab. There is not much space left on the front baffle due to where the speaker cutout was placed. I didnt consider adding drivers when I got this cutout. I am wondering what the experts on here think about adding 2 x Faital 3FE25 drivers using a 400w crossover - Crossover frequency: 2,500 Hz, 18 dB/octave HP, 12 dB/octave LP. Here is the driver specs FaitalPRO 3FE25

My goals are as follows:
- Add some high end clarity. Rather than just jack up the frequencies around the limit of the PR400 I would like the high end to cover a broader range if this makes sense. Should be smoother and generally have a better intergrated sound.

- Gain some off axis improvement in the high mids/highs. I would love to be able to crossover lower than 2.5k but that gets a whole lot more difficult and dont have the space on the baffle for bigger drivers that can handle the power.

- The high end gain must be smooth. The paper cone should sound smooth and being ferrite should break up nicer than neo ? Plan B would be to add 2 small soft dome tweeters and crossover at say 3.5k with no LPF.

My questions are:
1) Will 2 of these drivers have the power handling capability above 2.5k to match the PR400 ?
2) What impedance should these be and how would they be wired (series/Paralell) ?
3) Would you low pass the PR400 or run it full range - IE just use the crossover as a HPF for the 3FE25 ?
4) Would the 3FE25's be ok not having their own chamber within the cab ?
5) These have a 91bd efficiency. My basic understanding is that 2 should increase this by say 3db to say 94db. Is that a good match volume wise for the PR400's 99db ?

Hopefully a pic of the cab (albiet the wrong orientation) is showing the cab to date with a couple of paper cuttouts of where the mids will go)

Based on my own experience and seeing how the Mesa Subway 115 cab is designed, a 2.8 cu-ft enclosure tuned to 50 Hz should be ideal for the Faital 15PR400. I like the 15PR400 full range on its own but for my own taste also feel it benefits from some high frequency extension. I've been very pleased with the way a Faital M5N8-80 mid driver pairs with the 15PR400 woofer. Here is my build thread documenting this 15/5 cab. It's a bit smaller at 2.49 cu-ft tuned to 48.8 Hz. If I were to rebuild it, I'd go with 2.75 cu-ft tuned to 50 Hz, but the one I have sounds so good that it's not worth the time and money to chase this incremental improvement.
Faital 15/5 Build
I've tried a few different mid drivers and really like the voicing of the M5N8-80 with this woofer. Its high power handling and sensitivity (80 watts rms, 99 dB watt/m) is a good match with the 15" woofer and I found it to sound best padded back by about -2dB. It's a bit more mid forward with no pad. It tops out around 6.3kHz which captures everything from a bass guitar but the highest glassy treble. Also, smooth and articulate but not harsh. I built a 2-way crossover for this cab but run the woofer full range with the mid driver signal routed through a 2nd order Linkwitz-Riley high pass with a corner frequency of 1463 Hz, which provides good phase alignment and a more gentle slope with 0dB summing. This enhances the mids and upper mids and extends the treble with better dispersion without being over the top. I can switch the mid driver on/off for A/B comparisons and find the enhanced full range presence to sound better and sit better in the mix so I always have it on.
https://www.usspeaker.com/faital pro m5n8-80-1.htm

If built separately with 1/2" ply, this mid enclosure would be 7" square and 4" deep, lined with 1" acoustic foam. It could have an internal HPF filter and -2dB attenuator circuit (with switch for 0dB if wanted) connecting to a Neutrik jack which could connect in parallel with the 15PR400 cab. The HPF and attenuator are rated for over 400 watts at 8 ohms. I have Boxsim models which show frequency response, combined impedance, and phase alignment of this 15/5 pair. If you'd be interested in pursuing this I could provide these curves along with a circuit diagram if you'd like to build one.

One additional thought: If you'd be willing to rebuild your box with enough clearance between the port tubes to accommodate this mid enclosure it would be a cleaner build with the 5" mid atop the 15" woofer. It would sound amazing and you could also have a switch to engage or bypass the mid driver depending on the vibe you're after.