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Tuba HT


JasonJCarney

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Meh.... Maybe I'll just set this thing a blaze and end my misery!

Relax. A low pass filter is mandatory and it sounds like you have that covered, but the high pass is not. I don't have one on my tuba table and have no problems at all, and am not planning on using one on the Cinema F-20 currently under construction. However I am not out to impress the neighbors or shake loose the foundation of the house. The high pass is really needed if you want to crank it up, and mine seems to have plenty to offer without a lot of power.

Do you use yours for HT?

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Behringer BFD 1124P, Calibrated measurement mic,small mixer, a few cable bits, REW software, MIDI cable, PC. [Good news is all this stuff can be used in the future once you have it you'll get it.]

O-Audio is out, better for sealed designs.(due to boost curve hardwired in) Most Europower Behringer's are good. Visit The Home Theater shack dot com forums under DIY subwoofers, ported. Mike will give you advice and some of what I mentioned is available in the used gear there. I use a Peavey CS-800x with the setup mentioned above and it rocks my world. I should mention mic calibration is recommended but not always a big deal with bass measurement. The bad news, once you have the DIY sub bug your hooked, and it's worse than the Klipsch bug because there is no limit to design and room modes start you on the whole dampening and "I need a new room" quest. Enjoy!

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first I would like to thank everyone for all the help. I have kinda narrowed my choice down to 2-3 amps. I originally didnt want a plate amp but it is looking like that is going to be best bang for buck. So these are the 3 choices:

1. http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-807 upside is price and options downside is that its a plate amp

2. http://shop.emotiva.com/collections/amplifiers/products/upa1 upside is I know emotiva and like the products downside is only 350 watts rms and no filters

3. http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-811 upside is rack mount and options downside is price and reviews about actual power are a bit off

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If you are using the recommended dayton DVC driver in the plans then you will be fine without a high pass filter, you're fine as long as you aren't feeding the sub over 200 watts, and most people never even push 100 watts to their THT. I've been runing mine for quite a while now, haven't used a high pass filter since I had to get rid of the faulty Dayton SA1000. I'm glad I got the Behringer EP2500 and did the fan mod. I will be adding another THT in the future and will love having the flexibility to do so without changing amplification.

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I was looking at that but I can't seem to find reliable RMS power ratings for it. Plus for the same price the Emotiva is a know entity and I think 350 watts would be suffient. I guess the EP is not out of the question as it could provide more power but I would need to see solid rms ratings before a purchase. Anyone know where I could get more info about the actual power output on that amp?

I am putting 125 watts to it right now. It does give off some decent bass but I have to set my Onkyo to +12 on the sub level cal to get it. I am running 2 A5-350's as well and they don't like to be at +12...I basically have to almost shut them off at that level to have them sound normal. I may move the Tuba to the bedroom or to a friends basement HT. Although with the output Im currently getting I wouldn't feel comfortable reccomending it to my friend as his basement is quite big.

Also this is the driver that is installed in the Tuba http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-190

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Seriously think that something is amiss here, do you have an extremely large room? What is the voltage you are pushing to the THT (test with AC multimeter at amplifier speaker connections) Ask and you shall receive:

http://www.avsforum.com/avs-vb/showthread.php?p=10753603#post10753603

Also on the same thread they measure the Oaudio 500 watt plate amplifier which stacked up as one of the best budget plate amplifiers out there.

If you're honestly wondering if the Behringer amplifier is a good one or not, just trust those recommending it. It is dollar for dollar the king of DIY subwoofer amplifiers, and with an easy fan mod it is virtually silent. SO many of us DIY'ers use it as a sub amp and unless you somehow get a lemon, the amplifier is a trooper and takes a lot of abuse. For clarification, the behringer ep2500 is the same amplifier as the behringer ep4000.

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In that size room the tuba should be rocking your face off. Have you tried different placement options? Try different corners of the room with the sub facing into the corner at 18". Also check for air leaks on the access panel, and check to make sure that the woofer hasn't come loose In the enclosure/lost it's seal.

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ok....so to check on the woofer I need to take off the access panel right? Assuming thats good... how do I check for air leaks on the panel? I seriously doubt there are leaks present but you never know. I had an air leak on one of my A5's but that caused port chuffing not less volume. I will try moving it around the room to see if that changes anything as well. Unfortunately if the current placement turns out to be the issue then it will have to go. Either to the bedroom or my friend. My HT only has the one spot for it. Honestly putting a cabinet that is 36x36x24 off the corner 18 inches basically precludes it use in all but the largest of HT's. [:|]

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ok....so to check on the woofer I need to take off the access panel right? Assuming thats good... how do I check for air leaks on the panel? I seriously doubt there are leaks present but you never know. I had an air leak on one of my A5's but that caused port chuffing not less volume. I will try moving it around the room to see if that changes anything as well. Unfortunately if the current placement turns out to be the issue then it will have to go. Either to the bedroom or my friend. My HT only has the one spot for it. Honestly putting a cabinet that is 36x36x24 off the corner 18 inches basically precludes it use in all but the largest of HT's. Indifferent

It doesn't have to sit off the corner diagonally but can run parallel to one wall while being aimed at another with an 18"gap between the horn mouth and the wall.
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Well I really only have 2 choices in this room. Here are a couple pics so maybe you can see a possible issue with my placement. It sits under the staircase to the right of the main seating position.

1331866959.jpg

Here is the main listening position (pre tuba) for reference. Its an old pic but that is the right surround area

1307732053.jpg

...and this is the left surround area under the stairs

1331866979.jpg

So I can have the port facing the triangle notch of the stair case as in the above photo. Or I could turn it around and have the port facing the rear wall but I wont be able to get it 18 inches off the wall. I really could only get it about 6-8 inches off the rear wall. I did try both directions and iot didn't seam to make a difference in sound quality or output.

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I am putting 125 watts to it right now.

By what right and at what frequecies?

You've got to actually measure the voltage. You can't measure the watts in this instance, and you definitiely can not use your ears. Wait until you get that multimeter though, then all of this will start
making sense. You'll measure the AC voltage present at either the amp
terminals or the posts on the jack plate on the side of the sub, and the really good news is you
won't have to remove the cover to do this.

How do you have your subwoofer connected to your Onkyo?? Is it just running off a random channel, or are you running multi-zone and patching the sub-out back into the second zone channel(s)?

28V is what the THT will take. That voltage across a 5 ohm load is ~150 watts. So as long as you stick with an amp that's rated to put out an honest 150 watts into a nominal 4 Ohm load, then anything else is money to the wind. A single channel of your Onkyo might even be up to the task. [:o]

When you start attaching some numbers to what you're hearing, you'll be ready to get rocking. From skimming over the user's manual, I see that if you get your Onkyo set up just right, you may find you may not even need to buy an external subwoofer amp. [;)]

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Or I could turn it around and have the port facing the rear wall but I wont be able to get it 18 inches off the wall. I really could only get it about 6-8 inches off the rear wall.

Just saw your pictures...This would be the correct setup. 6-8 inches is okay. [Y] It won't kill it. Just slide it back to give it the most space it can have, firing into that corner. It's not going to make much difference in sound right now, because the electronics aren't dialed-in correctly yet.

As the filter and level settings are set in the future, that little change in placement will help out.

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I am putting 125 watts to it right now.

By what right and at what frequecies?

Im not sure what your talking about here. The M-282 puts out 125 watts at 4 ohms. There is no external volume or gain control on this amp so I am assuming it is set to full gain. I have the DB level control on the 3008 sub out set to +12 (highest). So all that said I assume Im getting 125 watts

You've got to actually measure the voltage. You can't measure the watts in this instance, and you definitiely can not use your ears. Wait until you get that multimeter though, then all of this will start making sense. You'll measure the AC voltage present at either the amp terminals or the posts on the jack plate on the side of the sub, and the really good news is you won't have to remove the cover to do this.

How do you have your subwoofer connected to your Onkyo?? Is it just running off a random channel, or are you running multi-zone and patching the sub-out back into the second zone channel(s)?

I have an Onkyo M-282 amplifier. I run RCA from the subwoofer preout on my 3008 to the left channel on my M-282. Then speaker wires from the left channel binding post to the sub.

28V is what the THT will take. That voltage across a 5 ohm load is ~150 watts. So as long as you stick with an amp that's rated to put out an honest 150 watts into a nominal 4 Ohm load, then anything else is money to the wind. A single channel of your Onkyo might even be up to the task. Surprise

When you start attaching some numbers to what you're hearing, you'll be ready to get rocking. From skimming over the user's manual, I see that if you get your Onkyo set up just right, you may find you may not even need to buy an external subwoofer amp. Wink

Im not even sure how you could run a subwoofer from the actual 3008 amp.

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ok....so to check on the woofer I need to take off the access panel right? Assuming thats good... how do I check for air leaks on the panel? ...

Here is a clip about testing the speaker:

Testing

Test your cab for leaks before attaching the access cover. Get a three foot length of flexible 3/8” to ½” plastic or latex tubing. Run a 20 to 25 Hz test tone at 10 to 12 volts. Use the tubing as a stethoscope, one end to your ear, the other run along all of the cabinet joints and around the driver seal with the baffle. The test tone will be very hard to hear, but the noise of air rushing through leaks will be easy to hear. Fill any leaks with a dab of adhesive. Attach the access cover with screws every three to four inches, using driver gasket tape (also available from www.speakerhardware.com) to seal the joint. After attaching the access cover check its joint with the cab for leaks as well.

Multiple cabs must be wired in-phase. To check phase run a test tone, anywhere from 40 to 100 Hz, though one cab, then plug the second cab in. The level should go up. If the level goes down you’ve either got the driver or jacks reverse wired in one of the cabs, or the cable connecting the two cabs is reverse wired at one end. Do this same test with subs and mains, using a test tone the same as the crossover frequency, to check for correct mains/sub polarity.

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