My Adire Audio Tumult-15 based subwoofer

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Hello,

I made the subwoofer last summer.
Here is a link with some info and two construction pictures (no final pictures yet, sorry). If you are interested, feel free to have a look at:

Link removed by moderation

Works quite well allthough my T-Amp 1400 is underpowered (only 2x700W to 4 ohms).

Best Regards,
Karoliina Salminen
 
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Karoliina said:
Hello,

I made the subwoofer last summer.
Here is a link with some info and two construction pictures (no final pictures yet, sorry). If you are interested, feel free to have a look at:

Link removed by moderation

Works quite well allthough my T-Amp 1400 is underpowered (only 2x700W to 4 ohms).

Best Regards,
Karoliina Salminen

Most important question is where are your neighbours ? :D
 
Neighbours don't propably hear it inside. It is possible to hear the rumble on intense parts of movies from their garden I guess. Anyway, I am not watching movies all the time, so that shouldn't be that much a problem.. The SPL I get is quite insufficient and the amplifier clips in intense parts of movies (and it does not sound good). The Tumult is quite insensitive and requires a lot of power to drive it. I have always wondered how some people say how well they drive their subs with some 100 W amp - there is no way to reach theatrical levels with that kind of power, kilowats of power is really required at the lowest bass.

It is interesting how much current is in the speaker cables btw, I got once already a electrical shock from the speaker cables. Was bad feeling enough to learn to not touch the cables again when the amplifier is on...
 
Re: Re: My Adire Audio Tumult-15 based subwoofer

Cordraconis said:
Where did you order it? I hope somewhere in Europe, as I don't like to use a credit card for overseas shipping.

I cannot see your worries. I have been ordering since 1995 and never had any problems. The proportion of people that do get problems are microscopic. However, if something happens, and you have the right company for your card, they take care of things for you.

If you go to Adires homepage, for europe there are these options:

AUSTRIA

Lautsprecherbau Wagner
Oberkogl 8
94113 Tiefenbach
GERMANY
PHONE: 0049 8509 934771
FAX: 0049 8509 934772
E-MAIL: awagner@ls-wagner.de
WEB: http://www.ls-wagner.de
GERMANY

Lautsprecherbau Wagner
Oberkogl 8
94113 Tiefenbach
GERMANY
PHONE: 0049 8509 934771
FAX: 0049 8509 934772
E-MAIL: awagner@ls-wagner.de
WEB: http://www.ls-wagner.de
SWITZERLAND

Lautsprecherbau Wagner
Oberkogl 8
94113 Tiefenbach
GERMANY
PHONE: 0049 8509 934771
FAX: 0049 8509 934772
E-MAIL: awagner@ls-wagner.de
WEB: http://www.ls-wagner.de
 
Karoliina said:
Neighbours don't propably hear it inside. It is possible to hear the rumble on intense parts of movies from their garden I guess. Anyway, I am not watching movies all the time, so that shouldn't be that much a problem.. The SPL I get is quite insufficient and the amplifier clips in intense parts of movies (and it does not sound good). The Tumult is quite insensitive and requires a lot of power to drive it. I have always wondered how some people say how well they drive their subs with some 100 W amp - there is no way to reach theatrical levels with that kind of power, kilowats of power is really required at the lowest bass.

It is interesting how much current is in the speaker cables btw, I got once already a electrical shock from the speaker cables. Was bad feeling enough to learn to not touch the cables again when the amplifier is on...

Just joked for the neighbours. I live in a building.

I agree for a kW, for subwoofers of that kind. Mms=270 gr, BL=19,4 N/A, Xmax +/- 30 mm etc.

How you went to 130 liter for that 15" bass? If you calculate with T/S parameters, for Vas=263 l and Qts=0,41 result is Vb=260-270 l and Fb=16-17 Hz.


If subwoofer have nominal 4 Ohm, it can be 3 Ohm at lowest. 10 Amper current at 3 Ohm is 30 V and 300 W. Problem is very low frequncy of that current, too.
 
Was based on the recommendation of Dan Wiggins:

The original discussion is here:
http://www.diyaudio.com/forums/showthread.php?postid=375181#post375181

Also if you calculate the SBB4 alignment for Adire Audio Tumult 15D2, that is exactly what you'll get (130 l, 16 Hz). With 260 liter box, you would get just 2 dB more output while doubling the size of the box and having more group delay at 20 Hz. I am not so sure doubling the size would worth it especially taking in account that it can be compensated with a more powerful amplifier (because the driver can handle that).

My driver is not the Tumult-15D4 (your Qts value was from that one).
 
Karoliina said:
Was based on the recommendation of Dan Wiggins:

The original discussion is here:
http://www.diyaudio.com/forums/showthread.php?postid=375181#post375181

Also if you calculate the SBB4 alignment for Adire Audio Tumult 15D2, that is exactly what you'll get (130 l, 16 Hz). With 260 liter box, you would get just 2 dB more output while doubling the size of the box and having more group delay at 20 Hz. I am not so sure doubling the size would worth it especially taking in account that it can be compensated with a more powerful amplifier (because the driver can handle that).

My driver is not the Tumult-15D4 (your Qts value was from that one).

Did you do your electrical measurements of the unit, or use T/S parameters from data sheet for calculating Vb?
 
Hello,

No I haven't done measurements for the driver other than the Re which verifies that it is D2 and not D4 unit.
Why should I if the driver functions well in the enclosure where it is now.

Specs:
http://www.adireaudio.com/Home/TumultSeries.htm

My driver Tumult 15D2:
Qts = 0.35
Fs = 16 Hz
Vas = 263 liters

I currently run the voice coils in series.

Best Regards,
Karoliina
 
I asked all this because I thought about calculations generally.
At example of Tumult 15D2 and Tumult 15D4 we can see paradox.

First, we must reconstruct all TS parameters. Mising Mms, Cms...

Tumult 15D2

Fs=16 Hz
Qes=35
Qts=0,35
Qms=14,1
Vas=263 L
Re=2x1,4 Ohm
BL=15,6 N/A
Sd=736 cm2
SPL(1W/1m)=86,8 dB

For 263 L and 736 cm2, Cms=0,347 mm/N and Mms=285 gr, but if we calculate with SPL, then Mms=306 gr. And if we go with Qes=(2*Pi*Fs*Mms*Re)/(BL*BL) then we got Mms=306 gr. OK, 2:1 for Mms=306 gr.

Almost the same unit Tumult 15D4, but with Re=2x2,8 Ohm.
With same Vas and almost the same Fs, it must be almost the same Mms, but..
Use Qes fomula and Mms=270 gr. Use SPL formula and got same 270 gr.

For Tumult 15D2 Cms=0,347 mm/N and Mms=306 gr wich gives Fs=15,5 Hz.
For Tumult 15D4 Cms=0,347 mm/N and Mms=270 gr wich gives Fs=16,5 Hz.

Dont conclude too early. Paradox is not diferent Mms.

Now, calculate Vb for Tumult 15D4 with some simulation program.

And what you got? Much bigger enclosure for almost the same unit which got smaller Mms.
I know transfer funcion is not the same, but in real, transfer funcion is not everything.
Thiel and Small did not envelope all influences at the transfer funcion, as: many kind of
compresions, termodinamic changes in enclosure, turbulencies in the BR tunel etc.

Sorry if I am boring, but I hope someone finds this interesting.
I do a lot of calculations od bass units with higher Qts, and compare it with real projects and find.....? Best results are with smaller enclosure and bigger Fb then you got with standard simulations (for high Qts). The bigger values of Qts and the differencies between real and results with simulations are bigger (enclosures are much smaller).

Qts of Tumult 15D2 is almost "ideal". With "ideal" I mean what you calculate that"s the best in real.

Best Regards,
Notax
 
Karolina,

If you aren't getting enough output, then it's far more likely that it's a box issue than a power issue. Doubling the power will get you another 3db at most and that's barely noticeable.

With that larger than necessary driver cutout it doesn't look like you can get a solid mount and air leaks are very possible.

The box looks like it can use some bracing, which is far more effective than a another layer of material like the fiberglass you mentioned.

Also, the port looks like it can use some smoothing and flaring.

Lastly, you may want to double check your actual port area and box volume. With a small box, large driver, and large port it could make a big difference in actual tuning.

You've got a nice driver and built a good looking box, so it's worth the effort to make what you have so far is optimized before throwing money at a new amp.
 
The output I get is higher than average people would think what is loud. I have driven my Fane Colossus 18XB driver too far and suffered with distortion etc. side effects of it. However, with Tumult, there is no much distortion coming from the driver, but the amplifier clips. The amplifier clipping occurred though with the Fane too, I am targetting at output levels above 110 dB continuous at 20 Hz with minimal distortion.

With the PA amplifiers, the increased power is cheap. The amplifier is placed in a different room, away from home theater room, so the fan noise etc. doesn't bother.

T-amp 1400 costed something like 350 euros or so when I bought it (it was dirt cheap). The amp I have been considering now costs no more than 600 euros (and produces over 2kW continuous).

Velodyne uses multiple kilowat amplifiers for reason. I know that doubling the power adds 3 dB, but quadrupling the power, I get 6 dB more headroom which is noticeable especially since I am nearly there, it usually does not clip, but in rare cases does, if there would be just a little more headroom, it would never clip.
 
>110 dB at 20 Hz is not that extremely dangerous, the ears are most sensitive to mid frequencies and conform with the A-weighting curve - the more noise you get to the sensitive frequencies of the ears, the more likely you are going to develop a hearind damage. Many industrial machines, slamming car door etc. makes more noise at 20 Hz (despite of hearing protection which does not protect from low frequencies) than my sub when it produces >110 dB at 20Hz. Some spend their days in that noise. Sounds loud on the paper, but is not that loud, it is just about the SPL used in movie theaters (which is A-weighted just below 85 dB at max peaks usually and so is our home theater, I have done some measurements). My dog used to bark at 130 dBA / mid frequencies, and he was surely more harmful for my ears than the sub. Jet engine destroys ears because it has excessive mid and high frequency energy and not because it has plenty of bass under that. We are flying with airplanes, and are now considering active noise cancellation headsets as it is more convenient with the upper lows to be supressed in addition to the mid and high frequencies (which is good enough with passive noise cancellation).

Also the sound damage depends on the dosage one gets. For example I do not use our home theater everyday, just about two times per week. Other than that I spend my time mostly in silence (pretty silent office) and when I am building something, I have my hearing always protected, I have a selection of Peltors around here :).

The Tumult sub is more loud (real loudness, not distortion) than the Fane Colossus 18XB used to be. The Fane sub used to distort its sound quite early as I was misusing it to produce the lowest bass range with it that it was not designed for. The first significant distortion what comes out from Tumult is the amplifier clipping.

I try to match the level in our home theater with the SPL level in a THX certified movie theater and prefer to watch movies at the SPL they were intended to be listened. I still need quite a less sound energy in the small home theater to achieve the same SPL than the big movie theater requires to do the same for hundreds of people at the same time. Anyway, if my result is less than that, then I am lacking something.

The realistic efficiency of Tumult in my box is around 82 dB at 20 Hz, therefore if I feed it with 1000 W I get 82 + 30 dB = 112 dB. My amplifier does not produce 1000 W, so I get some dB less like some 109 dB before clipping the amplifier. With 2 kW amplifier (that I mentioned before), I would get maximum 115 dB which would have some headroom over the 110 dB target before it clips. Amplifier clipping distortion sounds totally ugly. The t-amp has led indicators showing when it clips and in my use it clips with any driver, I used to clip it with the Fane too, I have clipped that one in the bridge mode which means 1200 W continuous / 8 ohms (but please take in account that its effective sensitivity at 20 Hz is less than the sensitivity of Tumult at 20 Hz despite the Fane is 101 dB/1 W efficient on paper).

The bottom line is that I am not having a problem, unlike many of you seem to interpret. The Tumult subwoofer functions excellently and is subjectively judged better than most subwoofers I heard on a recent Hifi exhibition. I am just doing some math about the last remaining decibels.

And it seems that I am not doing another box for this in any case, this one fits pefectly on its place and I have other things to build, I just purchased plans for a plans built experimental composite aircraft and I am going to start building it. And it will not have a subwoofer because it weights too much but I will surely install (propably Sennheiser) active noise cancellation headsets in it :).
 
Because we have less sensitivity to the lower frequencies, which often leads us to turn them up, we put ourselves at more risk. The sensitivity isn't directly related to the potential for hearing damage.

But watching a few movies a week at refernce level isn't a problem. When you said continuous levels above 110db at 20hz, I was thinking of something else entirely.
 
Karolina,

It sounds like you are really on top of it. I was initially thinking like Steve because I'm not goosing mine with nearly that much power. I guess the difference is that I'm running dual 15's and they're in a coffee table immediately in front of my seating position.
 
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