18" TC Sounds 5400 Ultra DIY

[phatfos1]

Just talked to Crown. They have a roll off starting at 20hz and although they don't chart for it in their literature I was told it's down 60db at 10hz. The guy I talked to seemed pretty knowledgeable and said most pro audio amps have roll offs at 20 and very steep as you get close to 10hz. I think if it plays down to 15 plus or minus 3db I'd be very happy. Just wish I could see some in-room measurements to give me a better idea of what I'd be looking at before I spend the money to get the sub and an amp. N8doog, you seem to know your bass and DIY...do you have any thoughts on the pro audio amps playing below 20hz?

[DYohn]

Most pro amps include subsonic filters. Some of them are variable some are fixed, but almost all are at least -24db at 10Hz. You don't need your amp to produce those frequencies in 99% of cases since the room dynamics dominate. Plus, if you use that TC Sounds Ultra driver in a sealed alignment it's not going to produce much output that low anyway. Like I said the lowest sealed f3 is approx. 49 Hz, there is no way you can get around the physics of that. I haven't modeled it but it should be down at least -15db at 20Hz. And since the fs of that driver is at 20.5Hz you'll never get that low in a sealed alignment in any case. You need to port that speaker if you want subsonics at any appreciable dbSPL. This sub looks like a beautiful transducer for general music use, but I'd port it and get that f3 down around 24Hz. THEN you have something.

[phatfos1]

Jul 18, 2013 16:10:05 GMT -5 DYohn said:

Most pro amps include subsonic filters. Some of them are variable some are fixed, but almost all are at least -24db at 10Hz. You don't need your amp to produce those frequencies in 99% of cases since the room dynamics dominate. Plus, if you use that TC Sounds Ultra driver in a sealed alignment it's not going to produce much output that low anyway. Like I said the lowest sealed f3 is approx. 49 Hz, there is no way you can get around the physics of that. I haven't modeled it but it should be down at least -15db at 20Hz. And since the fs of that driver is at 20.5Hz you'll never get that low in a sealed alignment in any case. You need to port that speaker if you want subsonics at any appreciable dbSPL. This sub looks like a beautiful transducer for general music use, but I'd port it and get that f3 down around 24Hz. THEN you have something.

Thank you DYohn! The more I think about it the less it bothers me that I wouldn't get much under 20hz. When you say you haven't modeled it, what do you mean? Is there a site that allows imputed speakers, amps and boxes to be compared? Where would I find that? How big would a ported box ideally need to be with this sub and the XTi 4002? Also, my system doubles as a music system so performace on music is also important. I know sealed allows more "punch" up the hz ladder. Just wondering if a ported box is the way to go for a music and movie system.

[DYohn]

I use software called WinISD to model speakers. There's also a good program for subwoofers called Unibox. Before you even think about building a DIY subwoofer you really need to either download one of these and model your system to see what you will get, or use someone else's design that is already proven.

A quick Unibox model of your woofer looks like this in a 4.5 cuft sealed enclosure, driven with 2KW:



In a 6.5 cuft enclosure ported at 23Hz, with 2KW, it looks like this:



So, the sealed performance is very good, but the ported performance is better, especially if yu want subsonics. Also note the red line. You do exceed peak excursion with 2KW input, so you might want to think about lowering that power.

[Deleted]

huh? what crappy pro amps are you guys talking about? Even the ep4000 are tested to be -3db from 20hz to 5 hz. It's not normal for amps to be like the crowns (their DSP are their own worst enemy for HT sub duty) The CV 5000, LG clones (tested -4db from 100hz to 5hz), the new peavy IRT2 7500 (I just got 2) are close to the same -3db from 20hz to 5hz. The crown XTi's are just not the best choice for sub amps, like the crown guy said, he fully admits it as well. Check out the avs forums tested amps pages. Tons of tested amps. These new peavys are in the process of being tested right now. So far looking like the guys were getting 2800 watts at 2ohms per channel with 1% distortion (held for 30 seconds before the breaker popped. They've gotten over 3000 but needed to upgrade their power delevery. Awesome for sub use! I've learned power is key, which is why I've got 4 x 30 amps lines and 8 20A lines just for my HT

Dyhon saying a sealed Ultra is not gonna rock under 20hz is nonsense. There are literally 50 builds at least on AVS proving otherwise with tested data to prove otherwise. They just need bigger amps. Just ask Eric (me even) or anyone else that has them in a 3-4 cf box how amazing they are with the right power.
Look what an ultra in a 4.2 CF internal box : www.data-bass.com/data?page=system&id=3 and thats outdoors, you'll likely get a bunch of room gain, 6dB's or so indoors
Check out what the driver can do VS tons of other tested subs : www.data-bass.com/systems It's a great driver but expensive. Check out the UXL 18 on there as well.

[Deleted]

Jul 18, 2013 18:32:42 GMT -5 DYohn said:

I use software called WinISD to model speakers. There's also a good program for subwoofers called Unibox. Before you even think about building a DIY subwoofer you really need to either download one of these and model your system to see what you will get, or use someone else's design that is already proven.

A quick Unibox model of your woofer looks like this in a 4.5 cuft sealed enclosure, driven with 2KW:



In a 6.5 cuft enclosure ported at 23Hz, with 2KW, it looks like this:



So, the sealed performance is very good, but the ported performance is better, especially if yu want subsonics. Also note the red line. You do exceed peak excursion with 2KW input, so you might want to think about lowering that power.

drop the box size to 3.5CF and add 2000 more watts of power, now were talking!

[DYohn]

Jul 18, 2013 18:39:16 GMT -5 @n8dogg said:

drop the box size to 3.5CF and add 2000 more watts of power, now were talking!

OK, here that is. Same f3, a little more output (predictably) and still exceeding XMAX.

[DYohn]

You can't change the f3 in a sealed system from what the math tells you is possible. Calculate it. Sealed f3 = 0.707 divided by Qts times fs. This woofer will always roll off right around 50Hz in a sealed alignment.

[phatfos1]

So much to learn. How can that Peavy IRT2 be 12 pounds and the XPR-1 weighs north of 90lbs with less power? What is in the XPR that isn't in the pro audio amps? Caps, transformers, etc where is the weight savings coming from on these pro amps v. everything I have seen made for HT?

I was going to use a tried and true design (be it sealed or ported) for this sub. There are a ton out there. Any idea where I would find the best?

[phatfos1]

N8doog how loud are the fans in those CV amps? The CV-2800 is very reasonably priced...what's the draw back on that? What would you say would be the best match in the $500-700 range?

[Deleted]

Well, I didn't mean for you to actually sim it lol. Thats what most of us do with it. Mech is 54mm, easily handled by the motor and in the smaller box, the air spring prevents damage. I know because I did it for 2 years that way Could always throw down a hpf if someone was really worried, you'll need one for the ported box if there are any plans to get the most out of what the box/sub can offer depending on how it's tuned.

phatfos, the peavy's are peavy/crest's own class D design. It's a switching design. The XPR is just a different design, thats it, a different way to go about it. Neither is good or bad, just different. I run class D ICE amps in my HT, they are 1000 watts at 4Ohms and weigh 7 lbs.

You won't find many ported Ultra builds, if any at all, thats not why you by that driver. If ported is what your looking for, save yourself some money and get something else. People build small sealed boxes for the ultra, thats exactly what TC sounds wants people to do with it. If sealed, there is no tried and true design but most people build between 3.5 and 4.5 cubic foot boxes. It's one of the few drivers that does very well in smaller boxes that can take a crap ton of power. The smaller the box, the more power you can run to it because the air spring in the box prevents most bottoming and thermal is not an issue uless you are running pure sine waves through them but thats for all drivers, not just the Ultra.

Go on AVS in the DIY section. Theo the owner of TC sounds is on there quite a bit and may answer any question you might have. As well there are lots of driver designers on there that are happy to offer help if needed. Dyhon gave you are great start with some sims to see what you can get.

[Deleted]

Jul 18, 2013 19:09:08 GMT -5 phatfos1 said:

N8doog how loud are the fans in those CV amps? The CV-2800 is very reasonably priced...what's the draw back on that? What would you say would be the best match in the $500-700 range?

Most, if not all pro amps fans are loud as hell LOL. You can do a fan swap to a lower dB fan (thats what most people do)
The amp will depend on what design you go with, ported or sealed. If ported the ep4000 would be a good start, a tested and true 1966 watts RMS bridged in 4 ohms. It would also work in a sealed box depending on how big of a box.

The CV2800 is 2800 watts bridged to 4 ohms, thats would be about perfect for 1 sub. If you went with a cv5000, you could run 1 off each channel. The CV5000 has roughly the power of 1 ep4000 bridged per channel. They are great amps and based of the RMX 5050 and marathon 5050.

The CV 5000 regularly goes on sale for $650 from www.musiciansfriend.com and amazon as well. I'm not sure about the cv2800 as I've never had one. I haven't had the CV5000 but I do have 2 RMX 5050's and they are the same basic design.

[phatfos1]

Great thank you. I emailed TC. I will look for some box designs on the AVS boards.

Best place to get baltic birch?

[Deleted]

In my area only 1 wood place sells it. Windsor plywood. I've read certain HD's in the states have it as well, just have to go see.

[phatfos1]

Thinking about a dual passive radiator design. Thoughts?

[Deleted]

Not with the ultra, don't bother. If thats the case, make a vented box. You don't seem to really have any idea what you really want lol. You can't just buy any radiators either. Add another $600-$800 for 2 of them to run with the ultra. if you got the coin then ok but you have a budget and it's just not a good idea. Go sealed or vented, thats the best way to stay in budget.

[phatfos1]

You are right, I have no idea what I want. That's why I am asking all the questions haha and kind of the point of the thread! I just read a thread at AVS about PR with the Ultra and they seemed to suggest that they(PRs) alleviated some of the issues and concerns with port noise and tuning for the right in-room response. But alas, you are correct, I'm lost and have no clue as to what would work best in my room. I've never built anything--I've always just purchased the audio equipment that I thought would get work with my system and gone off what others suggested. The more I looked into DIY the more I started to see that my money could go a lot (LOT!) further if I put in a little work and did some research. Thanks for your suggestions. Are you satisfied you have enough bass with your paragraph-worthy list of subs?! I cannot imagine what all that sounds like and feels like.

[Deleted]

Actually no, I'm one of those guys who likes insane bass. I've currently have 4 more FTW 21's on order once the parts come in. In my new house (once it starts being built...) I've got plans for 24 x 21's lol

I'd just like to give you a option. you could get 2 x 18's like the SI audio or Dayton or Mach 5 IXL2 18's and get 2 for a dual opposed design or even 2 4 CF boxes and a CV 5000. Your bill would be under the ultra and you'd have more spl on tap. Your looking at the ultra and people say it's the best of the best, which is pretty much is BUT it's cost makes it not the best choice UNLESS budget isn't a concern. 2 of the ones I listed would yield better results for less money. I'd doubt you'll find anyone that will argue that.
If you do go with just one driver, I seriously recommend you look at the Mach 5 UXL 18. it's 95% of the ultra at half the price. You could almost buy 2 for one and have very close to double the performance. 2 subs is always better than one, especially if you can have almost 2 of the quality of the UXL vs the price of the Ultra.

[DYohn]

Jul 19, 2013 17:29:13 GMT -5 phatfos1 said:

You are right, I have no idea what I want. That's why I am asking all the questions haha and kind of the point of the thread!

I suggest you read this web site. www.diysubwoofers.org/

[ocezam]

Hard for me to add much to this thread as any sub starting with that driver is way out of the league I am currently operating in with my DIY 18". However, I did do a BUNCH of reading concerning amplifiers. My choice in a stand alone amp would be a Crown XLS series. Take your pick on power output...

Most of the other brands seemed to have LOTS of fan noise issues, and while fixable, why not negate the problem from the start?

Good luck on the project. It's bound to turn out incredible!


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