THTLP side plate?

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joblow88
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THTLP side plate?

#1 Post by joblow88 »

So i was reading that '' In this case create a virtual extension of the horn by facing it downward, the upper edge supported to place the mouth at about a 30 degree angle.'' and it gave me an idea wich is to make 30 degree removable side pannel to mount on a thtlp. Would there be any gain? i think it would be a good way to have deep bass outdoor event in a somewath easy to carry setup.
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Bill Fitzmaurice
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Re: THTLP side plate?

#2 Post by Bill Fitzmaurice »

It wouldn't get you anything that corner placement doesn't. As for using a THT for outdoor events, it's the wrong tool for the job. T60 would be the right tool.

joblow88
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Re: THTLP side plate?

#3 Post by joblow88 »

Ok. the idea would be to have a pair of t24 that carry around in my civic easily but to also have something when we want to treat ourself with the best electronic music. that is why im interested in the thtlp. inside i would alway put it in the corner. Is it not the right tool because of the lack of room compression there no reason to go that low and the t48 is efficient at what is reproduceable outside?

joblow88
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Re: THTLP side plate?

#4 Post by joblow88 »

I thought that the longer horn would give a flatter and higher sensitivity in the lows, where the idea of increasing the horn length with the side panels. Also i liked the idea of having casters to move it around so if i would set it up that way it wouldnt need the stability at the rear bottom. Im just trying to understand everything

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Re: THTLP side plate?

#5 Post by Bruce Weldy »

joblow88 wrote: Tue Mar 29, 2022 5:30 pm Ok. the idea would be to have a pair of t24 that carry around in my civic easily but to also have something when we want to treat ourself with the best electronic music. that is why im interested in the thtlp. inside i would alway put it in the corner. Is it not the right tool because of the lack of room compression there no reason to go that low and the t48 is efficient at what is reproduceable outside?
You really lose the bottom end outside. The THTLP needs the cabin gain you get from inside due to the components. A T60 has a much more robust driver and has more sensitivity by having a higher high pass than a theater sub. So, if you wanted to take it outside, don't expect anywhere near what you get inside - plus, you most likely don't have a limiter, so you'll probably blow it up before you get started.

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joblow88
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Re: THTLP side plate?

#6 Post by joblow88 »

I count to have a loudspeaker management system so i could high pass it to whattever is right for the environment. so if i high pass it at 40hz-45hz would it not be as loud as t48? I plan to use it mainly inside with a 50 100 person crowds. i just realy like the idea 15-20hz electronic music events. It is just that if it would work outside why not us it?

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Bill Fitzmaurice
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Re: THTLP side plate?

#7 Post by Bill Fitzmaurice »

joblow88 wrote: Tue Mar 29, 2022 8:09 pm if i high pass it at 40hz-45hz would it not be as loud as t48?
It would not. The THT is designed for use in a home, where it takes advantage of boundary loading, which is necessary for best results. As for 15-20Hz, getting that outdoors would require at least four THT. Sources that claim they reach 15-20Hz outdoors without a massive system never have RTAs that prove it. Even multi million dollar touring concert sound systems don't try to go much below 35Hz. I do have the RTAs to prove that.

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Re: THTLP side plate?

#8 Post by Bruce Weldy »

joblow88 wrote: Tue Mar 29, 2022 8:09 pm I count to have a loudspeaker management system so i could high pass it to whattever is right for the environment. so if i high pass it at 40hz-45hz would it not be as loud as t48? I plan to use it mainly inside with a 50 100 person crowds. i just realy like the idea 15-20hz electronic music events. It is just that if it would work outside why not us it?
A Titan is going to be louder than a Tuba. Do you really have any music with 15-20hz content? Have you ever run it through Audacity and looked at it to see what's actually there? The THT is designed to be in a living room or small home theater.

If you take it outside, you'll need a driverack or similar to have limiting.....and figure out what the limit should be on those drivers. I'd say build a T48 (it's louder, but not quite as low) or a T60 (it's lower, but not as loud). But first, figure out what you really need based on the content of the source material.

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Re: THTLP side plate?

#9 Post by Bill Fitzmaurice »

You can't tell what's being heard with Audacity, only what's contained in the media. What's being heard requires an RTA. Then you have to figure in equal loudness to know whether you can hear it or not. With home theater you can at least feel what you can't hear, but that's not going to happen outdoors. You can pressurize a room, you can't pressurize a field.

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Re: THTLP side plate?

#10 Post by ACUA »

You can pressurize a field but it would take a lot of equipment. If I set up my quad stack of 24”wide tuba45s I can make a lot of low frequency noise but as soon as you want 20-15hz with authority that is going to require like 20+ tuba60s or better.

I am not convinced about the warnings against using home theater grade drivers in pro applications or using Bill’s home theater subwoofer horns outdoors as being any real kind of bad. I have solved many problems using an an adjustable wrench to hammer something into shape. You just have to realize the limitations of the tool you are using.

I started out on this forum a few years ago wanting to reproduce ultra low frequency content. Coming from the insane car audio world I was excited to do low bass in a club setting. After a few years at this as a mobile dj it is not worth the extra effort to have any acoustical power below 30-35hz. Even below 35hz is pretty rare with the music that is requested regularly. If you have any kind of crazy crowd the noise floor is so high that what sound pressure you build below 40hz struggles unless you have a major wall of subs.

If I could start over a stack of titan 48 subs would be better for me.
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joblow88
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Re: THTLP side plate?

#11 Post by joblow88 »

So th thtlp is only good in a closed room because it is virtualy impossible to have theses low frequencies outside. Since puting sub in the corner of a room gives aprox 12dB of sensitivity would i have a 110db @ 35hz? because if it is the case i seem not too shabby. Could you have a portable corner that is a little flimsy or it need to be wall solid?

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Re: THTLP side plate?

#12 Post by Bill Fitzmaurice »

joblow88 wrote: Wed Mar 30, 2022 1:46 am Could you have a portable corner that is a little flimsy or it need to be wall solid?
It needs to be substantial, and a wavelength wide and high. A wavelength at 20Hz is 56 feet.
If you have any kind of crazy crowd the noise floor is so high that what sound pressure you build below 40hz struggles unless you have a major wall of subs.
When I first started doing concert RTAs I was surprised to see lots of content from 16 to 30 Hz. What was more surprising was that it was there whether the band was playing or not. It was even there in the afternoon, when there was no band. It turned out to be highway traffic noise from a half mile away. You couldn't hear it, you couldn't feel it, but you could measure it.

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Re: THTLP side plate?

#13 Post by ACUA »

At war level, some 100-110dbspl it takes an additional 20db just to reach equal perceived loudness in the 15-20hz range.

According to the spl charts, a proper tuba60 is capable of roughly 92.5dbspl at 25hz on 2.83v. Every doubling of voltage is 4x power(wattage) and 6dbspl increase. So at 50-55v, typical power handling of a lab12 or Lab15 driver you gain about 24-25.5dbspl for a max output of about 117dbspl on a single sub. Now for every doubling of subwoofer cabs assuming maintain power supply than you gain 6dbspl. To reach 130dbspl you need 4 tuba60 cabinets all driven to their maximum. Then depending on the distance the crowd/listening is from the subwoofer bank, you loose 6db every doubling of distance. At 20-40 ft away to compensate for the decay rate you have to quadruple the subwoofer bank size, it would logically take a bank of 16 tuba60s. That would be fun to have and deploy but damn that is a lot of rig!!!

I edited this post after a conversation with Seth about it.

I may be getting lost in this, I think I got it right.

2.83v into 8ohms = 0.35amps, 2.83X0.35=1watt

Double voltage = 4x the wattage = 6dbspl gain

2.83x2=5.66v
5.66/8=0.707a
5.66X0.707= 4watts
+6dbspl

5.66X2=11.32v
11.32/8=1.415a
11.32X1.415=16watts
+6dbspl

11.32X2=22.64v
22.64/8=2.83a
22.64X2.83=64watts
+6dbspl

22.64X2=45.28v
45.28/8=5.66a
45.28X5.66=256watt
+6dbspl

50v/8=6.25a
50X6.25=312.5watts

55v/8=6.875s
55X6.875=378watts

The difference between 45v and 55v makes a +1.6dbspl

Starting at 92dbspl and add 25.6= 117dbspl max output at 25hz out of a fat tuba60!!!
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Last edited by ACUA on Wed Mar 30, 2022 1:43 pm, edited 2 times in total.
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joblow88
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Re: THTLP side plate?

#14 Post by joblow88 »

ok thanks for all these enlightenment. For some reason i tought that the reinforcement wall would an elongation of the horn so the length of the wall would add up to the length of the tuba and therefor require a somewhat small area of a few
4x8 sheet with square iron support welded togeter. Seem like I was wrong again.

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Re: THTLP side plate?

#15 Post by Bill Fitzmaurice »

Indoors the wall doesn't need to be a wavelength in dimension, since you've got a another wall at either end and a ceiling. Outdoors it's completely different. You can get good wall loading down to 50Hz off the side of a house, but it takes an apartment building to get down to 20Hz.

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