a T48 + a simplexx?

[chiarini]

Hello! I'm new here - i don't even know how i found this but it has been very eye-opening to read this forum and Bill's suggestions.
I have a collective with some friends and now we would like to build our own sound system. The objective is mainly learning deeper how do sound systems work and then, of course, having a ss built by us for our parties.
We play mainly recorded music, outdoor around 200 people (but sometimes also indoor), mainly techno, electro and some DnB.
Long story short, we alread have 4 drivers, two 18" (FaitalPRO 18HP1030) and two 15" (FaitalPRO 15HP1030). Our first idea was to build 2 sub horn-type with the 18" and 2 mid-low ported-box (or similar) with the 15" (and later think about the mid and high frequencies), but i understood reading Bill's advices that a 18" horn doesn't make much sense.

So i was thinking, what about two sub 15" (for example T48) and two mid-lows 18" (for example simplexx 18in)? A big plus would be to be able to sometimes use the sound system in a "smaller version", using the mid-low as sub - with different settings on the DSP.
Does it make sense?
I checked the specifications of the drivers suggested for the T48 and i'm not sure if our drivers would work - our driver is 8 ohm (ok), fs is 40 Hz (Kappa15lfa is 39 Hz), but Qts is 0.34 (less than the Qts in the 4 suggested drivers) and Watts are 1000....does anyone have an idea if it might work?
I have the same doubts about the driver suggested for the Simplexx - here the Impedance and Watts are the same, but fs and Qts of our drivers are a bit higher.

Thank you a lot for your help! Also if you have time to share general suggestions about how to compare drivers, what is mandatory to be the same and what is less important, thanks!
Chiara

[Bill Fitzmaurice]

what about two sub 15" (for example T48) and two mid-lows 18" (for example simplexx 18in)? A big plus would be to be able to sometimes use the sound system in a "smaller version", using the mid-low as sub - with different settings on the DSP. Does it make sense?

No. T48s yes, but use them with real tops, which are never loaded with 18s. Sell those to help pay for the drivers for tops.

[Seth]

Hey hey, welcome to the party Chiara! My name is Seth. If you get a moment to fill in a bit of your profile, it's nice to know what part of the planet you're from.

[chiarini]

Thank you for the answers! Seth, i come from Italy but i write from Portugal, EU.

what about two sub 15" (for example T48) and two mid-lows 18" (for example simplexx 18in)? A big plus would be to be able to sometimes use the sound system in a "smaller version", using the mid-low as sub - with different settings on the DSP. Does it make sense?

No. T48s yes, but use them with real tops, which are never loaded with 18s. Sell those to help pay for the drivers for tops.

Thank you Bill. I'll try to explain it better cause i think i didn't: we have two 15HP1030 and two 18HP1030 and we would like to build two horn-loaded subs and two vented-box subs; we would like to build a system for mainly outdoor parties for 250-600 people, which could work from around 30 Hz.
We want to make the subs with the drivers that we have in a way that we could use them all together sometimes (splitting the frequencies smth like this: Sub 30-80, Midlow 40-400, Midwoofer 200-2500, Driver 2000-20000) and sometimes (in smaller pirate parties) just the vented-box + the midwoofer and the driver.
We still have to buy the drivers for midwoofers and drivers, and this time we'll make it after finding the design of the cabinets...
Thanks!

[Bill Fitzmaurice]

Midlow 40-400

That's what used to referred to as a kick bin. They've been obsolete for thirty years. You run subs up to roughly 100Hz, two-way tops from there on up. Adding another cab to cover what the subs and mains already handle is a waste of drivers, lumber, pack space and amplifiers. As for wanting to make use of drivers you already have: Trying to make use of an on hand driver to save a few bucks and ending up with a cab that doesn't meet your needs is a bad idea. https://billfitzmaurice.info/forum/post ... dit&p=1779

[chiarini]

I get your point, thanks! We'll discuss about selling the 18" we have (even if it's new, so we might lose money anyway).
Just for curiosity, what kind of cabinets make sense to build with a 18"?

[Bill Fitzmaurice]

The only ones I use them in, bass reflex subs. What it comes down to is which do you have more of, pack space or money? If it's pack space build horns. If it's money build bass reflex. Bass reflex requires at least twice the number of drivers and at least twice the amp power to drive them, so you need a lot more money than with horns.

[chiarini]

Hello! We purchased the plan of the Titan48 and we are reading it and getting ready to start building
Is there any way we can calculate the response of our drivers in it? They are FaitalPRO 15HP1030.
We would like to build it 48x24x24...I don't know if someone already calculated the segments to put in Hornresp...
Thank you!

[Seth]

FaitalPRO 15HP1030 Datasheet

[chiarini]

Heyy
Thanks Seth. Do you have any idea if they might work well with the Titan48?
Thanks!!

[Bill Fitzmaurice]

To check pro-sound drivers for suitability the acceptable Fs is between 22 and 50 Hz, Qts from 0.25 to 0.5, xmax no less than 6 mm....Maximum output isn’t about watts, it’s about driver displacement, T/S spec Vd... When comparing various drivers don’t look at the watts, look at the displacement.
T48 plans, Page 1.

[Seth]

Heyy
Thanks Seth. Do you have any idea if they might work well with the Titan48?
Thanks!!

I posted the link in your stead, for Bill to reference.

Most of the time following the guidelines in the plans will get you the results you seek. I used to think it was fool proof. However, in a recent thread, Bill ran the simulation on a driver that fit the specs and deemed it undesirable due to deep fluctuations in the response curve.

If it was undesirable, I think Bill would have steered you away. That driver should serve you really well.

I'm fairly certain it should be voltage limited to about 70 Volts. Bill, do you agree? 70v?

[Seth]

Just noticed the Re is pretty low, nearly what a LAB15 is... 5Ω

So, perhaps the voltage limit is more like 62v?

[Seth]

...We purchased the plan of the Titan48...
...We would like to build it 48x24x24...

If you can transport it, I HIGHLY recommend you build your T48's 36 inches wide. Or, as wide as you can possibly transport. The type of music you're intending to play, the fact that you'll be outdoors, and that you're planning to play to crowds of up to 600 makes this a very wise choice. In the lower frequencies, a single 36" wide T48 will match the output potential of TWO 24" wide T48's (without v-plate). If you build four 36" T48's with the FaitalPRO 15HP1030's, not only will you have an AMAZING bottom end, it will also do it's job on very little power, which may be of additional interest to you if you're running off generator power. If you can't do 36", but can do 35", do 35"... or whatever the widest is you can make work. 36" is an amazing beast. It doesn't get much better than that, no matter the brand or price tag. It's about as professional and Hi-Fi as you can get.

Build them wide. You wont regret it unless you need to regularly tote them up flights of stairs, wheel them around confined spaces, or can't fit them in your transport vehicle/trailer.

Definitely sell the 18's and use the funds to purchase another pair of 15's. Do not build any cabs with those 18's. It would be a complete waste of time and money. A huge mistake for you to try integrating them in any way with the T48's. 100%, sell them. Even at a loss financially is an investment and a gain in the quality of the system and sound quality.