Box and porting for Faital 15PR400

[morebass!]

I have an older Trace Elliot 1153 1x15 cabinet that I put a Faital 15PR400 (4 ohm) in and it's a little disappointing. It's not bad sounding but after hearing Interceptor's beautiful TL606/EV 15L this weekend I'm jealous. Compared to the TL606/15, my homebrew is lacking definition in the mids and low-mids and isn't as loud. It does have a sweet top end to it and seems to go a bit deeper, but in a blurry sort of way. From reviews on TB I'd think that the Faital would be more gutsy than this. Or is the Faital just a very flat speaker that doesn't color tone like the EV does? In that case I'd just like to clean up the low end - I can always eq in some low mids.

So maybe one of you cabinet gurus/WinISD experts can help me decide if there's something I can do to improve things. The cab volume is approximately 3.3 cu ft. That's with driver volume subtracted. I wasn't sure if I needed to subtract out the port volume too so I didn't. There are two tube ports that are 4" diameter and 4" deep. The only modification I've made is to apply foam mattress topper to the insides - the thick stuff that looks like an egg carton.

I've read that this driver does well in a TL606. Compared to that my cab might be a bit big and the ports might be a bit small. I'm not changing the size of either but I could add another port. So that's the first question. But before I go there, it'd be easier to change the port length. Any recommendations on which way to go with that i.e. longer or shorter? Thanks in advance!

 

[Passinwind]

So maybe one of you cabinet gurus/WinISD experts can help me decide if there's something I can do to improve things. The cab volume is approximately 3.3 cu ft. That's with driver volume subtracted. I wasn't sure if I needed to subtract out the port volume too so I didn't.

You do need to subtract the volume occupied by the ports. And what is your current measured box tuning?

 

[Prana Ferox]

If the volume is actually 3.3ft^3, the driver displaces (by the datasheet) .131ft^3, giving you 3.169 ft^3 which is actually a little small for that driver. 2 4" tubes 4" long are yielding a high-ish tune around 55-56hz, with a big bump about 75hz and an F3 around 52 hz.

I would try jamming a ball of socks or something to close up one of the ports and see if you like that sound better. That'll be a 39-40ish hz tune, much flatter through the low mids. You'll get tons of port chuff if you crank it but it'll give you an idea if you want to go that direction.

E: forgot the ports, that's another .06ish ft^3, putting you at 3.163. The ball of socks idea still stands.

 

[Arjank]

I have an older Trace Elliot 1153 1x15 cabinet that I put a Faital 15PR400 (4 ohm) in and it's a little disappointing. It's not bad sounding but after hearing Interceptor's beautiful TL606/EV 15L this weekend I'm jealous. Compared to the TL606/15, my homebrew is lacking definition in the mids and low-mids and isn't as loud. It does have a sweet top end to it and seems to go a bit deeper, but in a blurry sort of way. From reviews on TB I'd think that the Faital would be more gutsy than this. Or is the Faital just a very flat speaker that doesn't color tone like the EV does? In that case I'd just like to clean up the low end - I can always eq in some low mids.

The Faital 15PR400 is indeed a very "flat" speaker, it doesn't have a pronounced breakup in the mids that most of the "instrument" 15" drivers have. I have a 15" cab that has an Oberton 15MB500 with a similar mid response as the Faital, most of the time I dial in +6 to +10dB around 2.5khz to get a bit more spunk.

So maybe one of you cabinet gurus/WinISD experts can help me decide if there's something I can do to improve things. The cab volume is approximately 3.3 cu ft. That's with driver volume subtracted. I wasn't sure if I needed to subtract out the port volume too so I didn't. There are two tube ports that are 4" diameter and 4" deep. The only modification I've made is to apply foam mattress topper to the insides - the thick stuff that looks like an egg carton.

I've read that this driver does well in a TL606. Compared to that my cab might be a bit big and the ports might be a bit small. I'm not changing the size of either but I could add another port. So that's the first question. But before I go there, it'd be easier to change the port length. Any recommendations on which way to go with that i.e. longer or shorter? Thanks in advance!

The cab size (approx 93 liters) is ok for the 15PR400, "optimal" tuning would be around 40hz. The two 4" ports should be approx 7" deep (the original 4" deep ports would make for a tuning of approx 49hz)
With this "deeper" tuning you will get a slightly "leaner" sound, so there will be less "oompf" around 50-60hz. I don't know if that is what you're after.

 

[morebass!]

Thanks guys. Arjank, I confirmed the tuning at 49 hz with the rice test. Nice to know that the modeling works that well. My volume estimate and the driver specs must be pretty good. I remeasured everything and the ports are actually something more like 4 1/8" diameter which is probably insignificant and seems a little odd (Thanks Prana for the port volume calculation). I had already subtracted out driver volume so my total interior volume is 3.24 cu in. I guess that's moot with Arjank's spot-on tuning estimate.

My application is 4 string upright and bass guitar which I sometimes tune down to D. The fundamental seems to muddy things up and I'm ok with my svt210av cabs that don't put out much below 100 so I think I'd be happy with very little below say, 70 hz. But I'll want some heft in the 75 to 150 range where the little ampegs are almost but not quite enough (although I haven't tried 4 of them yet). With the Faital driver I may be able to EQ that in. I also have a Fdeck III that I can set to 75 or whatever. So 7" port tubes then?

 

[morebass!]

The ball of socks in the port seemed to improve tone at low levels so I extended the port tubes from 4” to 7” and the tuning is now at about 42 hz. It sounds smoother and louder in the lows. I can dial in mid bass for reasonable approximation of an EV (without the grit). I played some recorded material through it and it surprised me how good it sounded through the whole frequency range. This driver is amazing! Thanks to all for your help.