Sundown x12 tline question...

[bbeljefe]

If you're going to go to the trouble of learning and using Hornresp, you need to also be able to extract the TS parameters from a driver that's broken in, lest you're not really seeing what you think you're seeing.

Manufacturers typically report TS parameters from new drivers and those aren't going to be the same once the driver breaks in. And any software is only as accurate as the information you feed it so....

The good news is that t-lines are (contrary to popular belief) very forgiving in the basshead world. It's certainly true that they're finicky beasts with respect to full range use but for sub bass, most of the minutia people fuss over is really inaudible.

[Triticum Agricolam]

So, what I'm getting fully out of this, is that I should find hornresp and attempt a design from that? I've read hours and hours of tline write ups, but as I'm sure some of you guys are, you can only ingest so much information before it becomes meaningless, or you're like me and can get a decent grasp on the concept yet never fully understand it until you're put in a hands on situation. Guys I really appreciate the help thus far and I will surely post more ideas or questions on this thread regarding the build. Thanks again

I'm happy to model stuff in hornresp for ya, and then you can make decisions on what direction to want to go from there. I totally agree with bbeljefe, any modeling software is only as good as the data you put into it, and you have to know how to interpret the results. I still find it very useful though.

Disclaimer: I don't want to come across like Hornresp is the only right way to do t-lines. Its just one of many ways and its how I like to do them.

[SuperRed]

Triticum Agricolam how would I go about getting some help from you on modeling that for me? If that'd be a possibility, I'd be forever grateful Haha

[Triticum Agricolam]

Sure, here I'll kinda walk you through how I use hornresp, so you can see what's going on.

Before we try a T-line, I like to look at how a regular ported box will perform, for a baseline to compare against. This is the input in Hornresp for a 2 cf box tuned to 32 Hz with 40 sq in of port area:

For ported boxes, all we care about is the bottom half of the input screen. The top two rows of the bottom half (Sd, Cms, Mmd, Re, etc) are the sub specs. The bottom two rows are the box specs. For ported boxes we use Vrc (box volume), Lrc (box depth, can be approximate), Ap (port area), and Lpt (port length). Everything in Hornresp is in metric, you get used to it, you can also hit F6 when you have an input box selected and then you can enter in Imperial units.

Here is the output of that ported box on RMS power (1250 watts):

This is showing the typical, somewhat peaky, output you get from an X-12.

Now for a T-line, we will start with a T-line that has the line area equal to Sd and tuned to 32 Hz, like the ported box.

The inputs we care about with T-lines is S1, S2, & S3. Those are the line area fields. The Con field to the right is the line length. I have the line broke up in two segments. S1 is the beginning of the line, S2 is where the sub sits, and S3 is the mouth. I put 18 cm between S1 & S2 since that's about half the width of the sub, which is how far from the closed end of the line it can be put. The remaining 237 cm is between the sub and the open end of the line. It tunes it to 32 Hz.

Here is the output:

The dark grey line is the T-line, the lighter grey line is the ported box for comparison. We get a little bit better efficiency with the T-line at tuning, and a little more gain above the tuning frequency. The T-line should be slightly less peaky in output than the ported box was, but still pretty peaky. I would consider this design to be an improvement over the 2 cf ported box.

Now lets try a tapered line:

I changed S2 & S3 so the line is tapered. S3 is 1/4 of S1. The line is also shorted than the non-tapered line, but the tuning is the same. This is one advantage of a tapered line, they can be shorted for the same tuning.

Here is the output:

We gave up some efficiency at tuning compared to the ported box, but above tuning efficiency is still better. The frequency response is quite a bit smoother. This design is also MUCH smaller than the untapered line, and is smaller than the ported box too. It has a problem though, and that's air velocity through the vent. Here is what that looks like:

You can see it spikes to near 70 m/sec, we want to keep it at 30 m/sec or below. Need to increase the line area.

Anyway, that's a start to using Hornresp for T-line designs. Let me know what questions you have and I'll do my best to expand on them.

[Hugh G. Rection]

Thats a nice little write up on hornresp

I wish i would have had something that simply written back when i first started using that program.