Stereo Integrity's new HT Subwoofer - Page 28

Re: HPF for vented subs.

If a sub models within excursion limits without HPF , do I stil need to use one to filter out the below tuning distortion?
Why output below tuning is "mostly distortion"?

Thank you

Well, they list Le now. And they bumped Xmax from 20mm to 23.5mm

How can you keep the excursion under limits without a HPF? Are you running 10% of the rated power (60W)?

I'm pretty sure Le was there before. It had it in the sims I made months ago. But, yes they increased xmax.

Below tuning, the woofer can unload. At this point, the driver could effectively destroy itself if you give it too much power. This is not the old days of 30 watt per channel amps. Nowadays, huge amplifiers with tremendous power on tap can crinkle drivers if you give them a chance. So, yes use a vented enclosure to obtain the SPL you desire, but HPF the system so you can enjoy it for a long time. You will be very happy you did.

Keep cranking,

Robert

Le was not listed at the time Ricci tested the driver. You may recall all the confusion when Ricci used erroneous Le numbers.
There maybe more differences. I have three WinISD drivers - one based on old SI specs, one based on the data-bass numbers, and one based on current SI specs. All three model slightly differently

Could be like me looking for more extension in my critical viewing area
http://www.avsforum.com/t/1240371/high-output-8-tapped-horn this is what I currently have and while its awesome for the size the cut at 28hz is pushing me into a 13cuft 10hz tune with a bash 500w andsome resistor mods.



According to winisd it passes x-max at 8hz by 1.5mm but I highly doubt that amp can output power down to that level. Should put out the same level that I currently have and 110db at 20hz with maybe 100db at 10hz.. Two 18's in the same size box with about 1.5kw of power may be better but its more expensive and I can't run the system as loud as I do in the basement.

Thank you.
Can WinISD models be trusted to estimate the unloading?
If I read my model correctly, while excursion goes up below tuning, it's only slightly over Xmax at 10Hz.
600W signal into dual D4 in 12 cu.ft with 14 Hz tune.
Is it safe not to use HPF in this case?

But if all output below tuning is garbage then there is no reason to take the risk any way

Yeh, but what about the xmax of the stuff that might just sneak by at 5Hz or so? There in lies the problem. You cannot control what is hidden in those tracks on the movies. So, yes, HPF if you want to enjoy for a while. No HPF- well, it is a crap shoot. You might just coast along with no issues until the day you are having fun and the scene comes on and you do not have the remote or are in another room and--Too late! You have options, but HPF is the safest bet.


Keep cranking,

Robert

It's not that i dont understand. It's that im limited on space so i gotta maximize it.

My LS-C gets here next week so that'll pretty much take up all the space between the LS6's.

To be honest bro im completely happy with my bass system. Anytime I start to get that feeling to upgrade i just bump up the LFE by about 10db's and that feeling goes away.

But would not this be an issue for closed boxes too?

Not if the box is sized correctly for the driver & amp power.

We definitely had a Le from SI at the time Ricci's T/S measurements were posted. The graphs of the SI T/S parameters show the impact of Le.

Here:


From 10/16/2012:

ok, I am convinced that HPF is a must for vented enclosure, especially with this driver. thank you for the guidance.



Edited by zheka - 1/9/13 at 7:08am

If I am not mistaken, you used wrong Le from Josh, made public by Nick of SI
here is snapshot of all three versions of WinISD drivers I have.



yellow- original SI specs
blue -current SI specs
red - data-bass specs

actually the very first post in this thread lists Le. So you must be right, SD. My bad.

Well, Le value here is not quite as important as you think. Josh used his measurement because Le is measured at 1KHz, so in the realm he was testing the value would be valid.

Hey, I hope they are right which means 4 ported subs will outgun 8 sealed by 6 dBs at 10hz! For $1000 one can get 122 dBs at 10 hz outside! My system gets me 115 dBs at 10hz in winisd and I measure 15 dBs more in my room at my LP so 4 LLT's would get me 137 dBs at my LP at 10hz at 1/3 rd the cost!

you should know ported outshines sealed up to a certain point.

Loud, low, small



Pick two and design around that.

I know, I am just saying, supposedly two of these with a LLT models just as loud as 10 sealed of these at 10hz. Both are around 116 dBs at 10hz at 1 meter. Can this be true? Seems like something is wrong.

Are you modeling both with the same watts?

I never ran the LLT thru winisd but I did run 10 sealed with 6000 watts.

I am using my phone right now so I can't do it tonight. I will compare a few systems. I know what my 12 drivers model and I know what I get in my room so I have a good idea what to expect from sims and at my LP.

Twelve 12's is equivalent to four 18's. So it's like you have four of these drivers already, James. Model it like that and maybe it will start to make sense.

I'm quite confident in my models.

If I model my drivers with 7000 watts and 10 SI drivers with 6000 watts I get around 3-4 dBs difference at 10hz. It gets lower as I move up in frequency. It is more like a two to 1 not 3 to 1. Again just at 10hz and I hit well over reference with what I have so getting more capable drivers would be wasted because I have to turn these down already. When I measured just one driver I was 5-6 dBs down at 10hz. That is with eD's enclosure which is too big for these drivers, I could use more power with a smaller box as they can take more. If I built my own boxes I could get it more like a 3.5-4.5 dB difference between drivers(one for one).

The bottom line is if I bought 12 of these I would gain 6 dBs at 10hz so now rather than hitting 127.5 dBs at 10hz I would hit 134 dBs. The bad is I will never use the full potential from both systems. I know for a fact that the 22 inch cubed boxes(is 20 better?) would look much cooler because it would actually make a baffle wall because there would be no gaps from my front stage.

I will show the sims tomorrow because they are on my work computer, I am on my phone. I never even bothered to run the LLT sims. I know my room gain and my spl limits at LP(10% THD limited) so the sims I ran show about the right amount of gain at 10 hz.

Scott

are you using a HPF with your LLTs?

Here are the sims between what I have(using half my amp power) and 10 SI's, and then 4 LLT's. All these sims are using boxes and power that limits excursion at the same frequency.

Like I said, more like a 2 to 1 comparison, LMS 5400 is 3 to 1. How do you guys capture the Winisd graphs?

I have found with my old LLT's that if you have enough output for reference and a very low tune like these(I had a 13.4 hz tune) a HPF is not needed. It is always a safe bet though and the higher the tune the more you need it. The reason for this is that under 10hz you have electronics rolloff and also the material is usually recorded lower as well so you don't need as much spl.