SHOOTOUT! Epik Empire vs HSU VTF-15H vs CHT CS18.1 vs Rythmik FV15 vs eD A7s-450 - Page 38

Originally Posted by cschang

the concrete slab does not move, and doesn't transfer anything.

How does a concrete slab transfer vibrations if itself doesn't vibrate? Think about it.

Originally Posted by mannoiaj

I agree Tack for the most part. I'm just not going to bust their balls about it as I'd like them to do it again. It's a nice nugget of info for sure to a guy like me... but I agree with you that it doesn't need to be defended and primitive graphs aren't going to help anything. It is what it is. They called it like they saw it and thats cool.

It would vibrate a bit. You don't need to think too hard to realize that.

Originally Posted by mannoiaj

It would vibrate a bit. You don't need to think too hard to realize that.

Originally Posted by McStyvie

I have nothing more to add on that topic really.

Originally Posted by MKtheater


I have a concrete floor with carpert over them. 8 18's can't vibrate concrete!! I actually like this as you feel the subs and not the room. I have tried very hard to get rid of all rattles and such and wish my second row riser was concrete and not wood. The wood resonates too much.

Originally Posted by KJSmitty

I'm not an expert in the referenced subs yet live in TX where slab/very thick concrete foundations are the norm. Been in many a good HT with subs better than mine yet regardless, the slab would not vibrate nor would it transfer any vibrations. The only thing that would/did vibrate my foundation/slab is either an earthquake or the extremely large earth mover that dug my pool.... IE, to vibrate the slab you would need to vibrate the ground it sits on. And that would take an impressive sub.. :-)

Cheers

Originally Posted by MKtheater

Yes indeed, I always tell people that it is much harder than one would think to get that tactile feeling at my seats with concrete floors(even in a 2200 cubic foot room). Once you do though, it is all bass and not the floor shaking which IMHO sounds much cleaner.

Originally Posted by below90hz

As for slabs, why are we still talking slabs? I checked into what chang said and conceded he is correct that conc slabs would not transfer vibrations. The point I differ on is whether or not subs transfer vibrations through floor joists/subfloor.

Originally Posted by dominguez1

So let me try and recap:



Below90 suggested in the above graph that if all the subs were calibrated with a 25hz sine wave (instead of the AVR's rumble tone; 30-100hz), then the shapes of the curves would not change, but shift. This would give the CHT a favorable curve compared to the others.

However, Bosso pointed out that if this had happened, the CHT would have to run 'hot' 6-7db compared to the other subs. But even it did run 'hot' at 25hz, its max output still would not change and be less than the other subs from 25hz and below.

My question is: do max output curves typically have the same shape of the 'calibration' curves? If this is true, would the max output curves revert back to generally the original plot below, thus supporting Bosso's point that the CHT would revert back to having the least amount of output below 25hz?

EDIT: If they do stay the same general shape, the max output curve would only shift the curves up or down.



I believe in the a7s-450s case, the max output curve would look much different (from 25hz and below or so) than its 'calibration curve'. The a7s has a high pass filter (HPF) at 18hz or so with a 12db slope. This was implemented as a 'safety mechanism' as they used to produce it without the HPF (and the amp can be modded at request to remove the HPF). When running max output tests, the HPF really doesn't come into play and the 'true' frequency curve will be revealed.

That being said, if the max output curve shows more output than its 'calibration' curve, then that should give you an indication of its ability to handle EQ and also the sub's associated headroom, correct?

Originally Posted by cschang

It was McStyvie and mannoiaj that said the slabs would vibrate or transfer vibrations..

Yes...wooden subfloors/joists can transfer vibrations, but it is depends how well they are built. It think they cause more resonance than they do actual shaking.

But also keep in mind, that walls vibrate just due to sound output, and that is transferred to the floor as well.

Originally Posted by mannoiaj

Curtis, I was pretty much talking out of my ass. I'm sure you're right, it just seemed to me at the time that they would vibrate a bit. Sorry to anyone who may have thought I knew what I was talking about and led them to be misinformed. I'll do my research next time before making a post in such a matter.

Originally Posted by dominguez1

Anyone? I'm really interested to hear thoughts around my question about max output curves:

Do max output curves typically have the same shape of the 'calibration' (AVR rumble tone) FR curves?

Below90, if no one has understood your graph above...please explain?

Originally Posted by ironhead1230

The response of most subs I've seen measured does change when you reach the limits. This can be caused by reaching excursion limits, limits of the port, amp limits or a limiter or protection circuit. Some change more than others. Here are some examples.











This is why I think it is important for people to not only measure their response at 75 or 80db, but keep raising it until compression. This will give an idea of the limits of your sub. Something else to keep in mind is these max output graphs are not necessarily the max short term output of the sub. The peak CEA2010 numbers and what you can reach during movies or music will probably be higher then the sweep numbers. One other thing you can see from their measurements is when the response starts changing, most of the time distortion increases dramatically.

I don't know if that answers your question, but look through Ricci's and Ilkka's measurements and you can get an idea of how the response of different subs change as the levels are increased.

-Mike

Originally Posted by cschang

Oh...no worries. Just put a emoticon or something after your post.

Originally Posted by MKtheater

If Ricci used the bass boost and got rid of the HP filter(both can be done from eD) it would be much flatter and had very little compression with the 120 db sweep. Impressive, no wonder my 8 eD sealed system moved some serious air.

Originally Posted by BiGBADDABOOM

The eD would exceed max excursion without the HPF, model it.

Originally Posted by BiGBADDABOOM

The eD would exceed max excursion without the HPF, model it.

Originally Posted by yadfgp

Sounds like maybe eD should lower it a bit though?

Originally Posted by ironhead1230

The response of most subs I've seen measured does change when you reach the limits. This can be caused by reaching excursion limits, limits of the port, amp limits or a limiter or protection circuit. Some change more than others. Here are some examples.

This is why I think it is important for people to not only measure their response at 75 or 80db, but keep raising it until compression. This will give an idea of the limits of your sub. Something else to keep in mind is these max output graphs are not necessarily the max short term output of the sub. The peak CEA2010 numbers and what you can reach during movies or music will probably be higher then the sweep numbers. One other thing you can see from their measurements is when the response starts changing, most of the time distortion increases dramatically.

I don't know if that answers your question, but look through Ricci's and Ilkka's measurements and you can get an idea of how the response of different subs change as the levels are increased.

-Mike

Originally Posted by below90hz



And some of you are trying to extrapolate information from it that just isn't there.

Originally Posted by mannoiaj

Curtis, I was pretty much talking out of my ass. I'm sure you're right, it just seemed to me at the time that they would vibrate a bit. Sorry to anyone who may have thought I knew what I was talking about and led them to be misinformed. I'll do my research next time before making a post in such a matter.

Originally Posted by McStyvie

Ditto

Originally Posted by cschang

No worries. I didn't think you knew what you were talking about, which is why I tried to explain. Glad to know you learned something.

Originally Posted by Madaeel

This is exactly what had Ethan and I so perplexed before. The HSU had the least average output yet shook the room more than any other sub, except maybe the VS we just got done listening to. When we said maybe because it had larger feet than the others so more surface area to transfer the cabinet vibrations, someone said they highly doubted that was the reason. However, when you are building a room for sound isolation with regards to bass the least points of contact you have with the adjoining rooms the better. That way the bass has less paths to travel. Room within a room is considered the ultimate isolation. Isn't that also why people use great grammas?? To decouple the sub from the floor? I'm not saying that's the only reason just maybe one of the factors involved. If that is true then the Empire would still be at a disadvantage.

The eD 450 had the highest peak spl followed very closely by the CHT. Yet the HSU shook the room the hardest followed by the Rythmik. So the correlation between spl's and resulting vibrations is kind of hard to figure out. Maybe someone else can chime in and enlighten us.

Originally Posted by Madaeel

Thanks Pete for sharing your thoughts. When this was brought up before that's what I initially thought. However, I dismissed that notion because I thought the Rythmik and Epik had more output below 25hz then the HSU. It never occured to me that that was just in regard to it's FR and not max output or whether or not compression was playing a part. Bosso has mentioned to me, and on other gtg/shootout threads, to use speclab to see where the spl's we're reading are in relation to the frequencies in the scene. I mentioned it to Ethan and he agrees that's something we'll do from here on out. Between that and using REW next time we should be able to figure it out. Right now we have no idea for the effect it seems other than maybe the cabinet vibrations or deep bass output. Thanks again for stopping in Pete.

Originally Posted by ironhead1230

I think I have mentioned it before, but another thing that can be done is doing sweeps at increasing levels until compression occurs. Just like the graphs I posted earlier. This will show if any sub starts losing output at specific frequency ranges at higher levels. Just because a sub has the most output below 20hz at 80db, doesn't mean it will still have the most at over 100db. IMHO, this type of measurement would be a great addition to any shootout, comparison or review.



-Mike