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Ricci didn't do any comparisons with his LLT, he used sealed subs. I'm extremely confident that two high excursion 18" driver LLTs would best the folded horn below 30hz....by a fair margin too I'd have to think - above 30hz I don't really know if it matters because the pair of LLTs would already be capable of over 115db. I guess if you have a really big room and sit really far from your subwoofer, the horn would make a difference at that point.

soho, no resistance, I am all for dynamic capability as well. I was just saying that it terms of going after the weakest link first, I would target the woofer section of a 3 way main speaker. After that, the rule of diminishing returns will start to play a factor. But if you can do it for roughly the same cost without much additional work, then by all means, it makes sense.
 

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Well actually with compression you would have never hit 112dB to begin with, so when you factor back in boundary gains it ends up about the same. ;)
Not quite the same...

You're assuming that the boundary reflections are in phase with the direct signal and that the reflections don't arrive very late.

Another nice thing about horns for the HF is that it allows more control over the polar response. Early reflections that cause blurring of the image can be avoided, and it's also possible to make the off-axis have the same frequency response as the on-axis, which has the benefit of tonally balanced "reverb" in the room.
 

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Ricci didn't do any comparisons with his LLT, he used sealed subs. I'm extremely confident that two high excursion 18" driver LLTs would best the folded horn below 30hz....by a fair margin too I'd have to think - above 30hz I don't really know if it matters because the pair of LLTs would already be capable of over 115db. I guess if you have a really big room and sit really far from your subwoofer, the horn would make a difference at that point.
oh yes, my mistake! But then again, I'd guess that a pair of XXX's sealed with his power and internal volume, he just might have similar sub 30Hz output as say 2 MX 18's in an LLT hehehehe!
 

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Discussion Starter #124
But then again, I'd guess that a pair of XXX's sealed with his power and internal volume, he just might have similar sub 30Hz output as say 2 MX 18's in an LLT hehehehe!
:T. Right it'd be similar. I can present the simulations if you really want.

I should be able to post what's what exactly between the DTS10 and the XXX's below 30hz after the holiday weekend. The DTS10 is no slouch that falls on it's face below 20hz. It gives door rattling 14hz sinewave output cleanly. Gimme a few days.
 

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Steve, I didn't mean to direct that at any one person. I have a bad habit of only hitting the forums under times of... duress. It kind of bleeds in sometimes. It's kind of an outlet.

I was just saying that it terms of going after the weakest link first,I would target the woofer section of a 3 way main speaker.
I'm not following here. Are you talking about a commercial speaker? In my example above the tweeter is the weak link. Nevermind, don't worry about it. This is getting for far off track.


Dr Who, just trying to keep things simple. ;) What I was trying to get across that was that in the real world you would never get the full predicted SPL at a high power rating, so you can't just take an inflated predicted number and expect to pick up a few more dB from the room from higher range frequencies.
 

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I am interested in how people will finish them myself. I will have mine next week and I was toying with the idea of seeing if the trade school in my town could do something like paint in the auto shop or veneer in the woodshop. Carpet would be cheaper so I might just do that especially if I use it as a riser.
 

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:T. Right it'd be similar. I can present the simulations if you really want.

I should be able to post what's what exactly between the DTS10 and the XXX's below 30hz after the holiday weekend. The DTS10 is no slouch that falls on it's face below 20hz. It gives door rattling 14hz sinewave output cleanly. Gimme a few days.
Looking forward to it! Thats what i have been waiting for!
 

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How are you guys finishing these beasts?

Id prefer it to be as easy as possible, possibly carpet?
Carpet is an option. I've done many a car subwoofer box that way.

I am interested in how people will finish them myself. I will have mine next week and I was toying with the idea of seeing if the trade school in my town could do something like paint in the auto shop or veneer in the woodshop. Carpet would be cheaper so I might just do that especially if I use it as a riser.
I believe the cheapest option may be a flat or semi gloss latex paint in your choice of colors. I threw 2 coats on my LLT and it was less than $10. For this thing a gallon would probably be better. The carpet would definitely work better if used as a riser.
 

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This sub sounds like a beast :)

Might have to try one of these (or something like it one day).

How does it go for music ?
 

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Discussion Starter #134
Here's some info from the last week or so.

I've managed to make a small improvement to the basic DTS10 response by adjusting the phase further and I've applied 2 small EQ cuts to the top end to bring it down in level a bit. Not a huge difference but a slight improvement. I never did flip it like Bosso suggested yet.

Before and after.




Here is the averaged response over 7 positions spread throughout the room. Also before and after.


 

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Discussion Starter #135
This is a repeat of the dynamic output test to see the max short term output levels using the 3 samples out of a Fruity Loops pack. 2 different kick drums and a 25hz bass pulse. I did not bother to log what my 2 CM140 meters registered this time because they do not represent what is happening during a short event like these well at all. More on that later. I do have my microphone calibrated to match the electrical signal strength from the LFE pre-out fairly well now. The levels that these waterfalls represent are probably well in excess of 120db peak. The DTS10 was louder than the 2 sealed 18's on this test courtesy of the extra efficiency in the meat of the kick drum range. Both sub systems were amp limited on all 3 samples.

The electrical of the 3 different samples at the level the subs were tested at.





Each waterfall has the electrical signal directly below it for reference sake and the top one is recorded through the ECM8000 microphone.




Dual XXX's Kick drum sample 1




DTS10 Kick drum sample 1





Dual XXX's Kick drum sample 2




DTS10 Kick drum sample 2





Dual XXX's 25hz Bass bang




DTS10 25hz Bass bang





Now for reference to the kind of output levels these represent, consider that I had to turn up 15db past where my REF movie level setting is to get either sub system close to clipping with these kick drum samples. To the point that the electrical signal would be way hotter than anything coming off of a movie soundtrack at REF even with everything below 200hz redirected.

The electrical signal of a 16hz sine wave that measured at 111db on a CM140 with the XXX's is presented below. Consider that the CM140 likely reads a bit low at 16hz and compare the strength of the sine wave electrical signal to the ones of the kick drum samples presented above. I let you guess what kind of peak SPL levels they represent. I have no doubt that they are well past the 113-115db shown on the CM140 read-out.



 

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Discussion Starter #136
Power compression tests.

5-100hz. I removed all EQ from both sub systems, set the xover to 200hz and also turned off the mains. The microphone was at the listening position. Each sweep was a 1M 22sec sweep out of REW at maximum level I started at -27 on my receiver and each sweep was increased by 3db up until -9 for both sub systems. I didn't go any further with either. The XXX's because of amp clipping in the 70-80hz range(I believe) and the DTS10 due to a lot of compression showing up in the 10-25hz band. The amp never did clip, but I believe that the drivers may have been reaching their limits on the low stuff. Heard what sounded like the drivers distorting on the lowest stuff(mouth overload?). No dedicated HPF other than what is in my electronics and the amp were used with it, so that seems to indicate that it'll take quite a bit of over blown sub 10hz content to damage the drivers. The XXX drivers were almost out of excursion 10-20hz as well. I don't think there was much left in either system to pursue further. Either way I knocked a bunch of stuff off of the walls and everything in the house was violently rattling so it's hard to say exactly. The pair of XXX's appear to have a slight headroom advantage below 25hz and show less compression there. The DTS10 dominates above 40hz and likely has a lot left in the gas tank if you have the amp for it. Wicked top end output and it suffered much less compression than the XXX's above 30hz. The maximum level recorded by my CM140's during the XXX sweeps was 120.2db and a massive 127.3db for the DTS10.Most of this from the 75-95hz range where I started to wish that I had put ear plugs in.


Dual XXX's sealed.




DTS10




Here is the starting sweep for the 2 sub systems. Black is the XXX's





Here is the maximum output sweep for each system superimposed. Black is the XXX's.



Here is the starting sweep and maximum sweep for both systems. The black and blue is the XXX's. Both systems had the level increased the same amount in total.








Bon Appetite!:D
 

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Thanks for all that work, it is appreciated :T

That horn FR is kinda nuts - I realize a major part of it is your room, but to get somehing resembling a flat response, you'd have to use quite a bit of EQ cuts, bringing down the overall output energy of the system a a given time. Below 30hz is a little better than what I was expecting, but still not reference capable.

I am excited about the potential of using horns for the woofer section and possibly even midwoofer (nod to soho) of my eventual pair of DIY mains though, I'm sold that that is going to be a great option. I'll have to find someone who has already done it, as I don't think there is an easy way to learn how to design horns, is there? , if I get nuts enough, I may even use a waveguide for the tweeter.
 

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That horn FR is kinda nuts - I realize a major part of it is your room, but to get somehing resembling a flat response, you'd have to use quite a bit of EQ cuts, bringing down the overall output energy of the system a a given time.
I believe Ricci is toying with getting a second one. The two XXX's he has are in different positions in the room. One in a corner and I believe one along the back wall closer to the center. Two would flatten the sound out as he has experimented with placement of two subs pretty extensively.
 

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Discussion Starter #139
Thanks for all that work, it is appreciated :T

That horn FR is kinda nuts - I realize a major part of it is your room, but to get somehing resembling a flat response, you'd have to use quite a bit of EQ cuts, bringing down the overall output energy of the system a a given time. Below 30hz is a little better than what I was expecting, but still not reference capable.
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You are kidding about the Ref capable below 30hz right? Remember the sweeps are 22second long logarithmic and pure sine waves. No movie has pure sub 20hz sine waves at full out 0db.

The FR is totally the room. A 2nd one will even out almost as smoothly as the 3X's.
 

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Discussion Starter #140
Consider this simulation.


This is just a simulated exercise, but this is what I appear to be experiencing out of the DTS10. The orange is again the max 1 m output from the dual sealed XXX's on 6500w, the blue is what I have simulated for the DTS10 and for reference to something many people around here would be familiar with the green trace is a Mal-X 18 ported to 14hz on an EP2500. The 13-18hz area for it is probably a bit overstated as there's always some port compression around tuning at the highest levels in reality. As you can see the 2 XXX's will outperform a very solid ported 18" driver in every way. They make a very powerful sub bass system. So will the DTS-10 once you factor in a bit of compression from both systems. It's quite comparable and graduates to a whole other league once you get out of the 10-20hz band.










Regardless of whatever SPL levels I measured it is relative and in my room any sub placed in there will be subjected to the same acoustics issues. Don't go comparing the output #'s I got to any other ones measured or projected by anyone else. Don't think "well Ricci only measured 115db at 20hz with the DTS10 and I measure 120db at 20hz with my ported 15 in my room, so it must not be that powerful". That would be wrong thinking. Look at the simulation above and consider that green trace for the Mal-X ported on a couple KW of power compared to the blue trace which would be on a similar amount of power. Again the graph above is just a guess but it is somewhat educated from playing with the DTS10 for the last few weeks,so I'm willing to bet it's in the ball park.

BTW I would've simmed this stuff in HR but that would take awhile and it doesn't allow you to compare the graphs so easily.
 
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