Which sub do you have in HT system?

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grampi

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Originally Posted By: sleddriver
Originally Posted By: grampi
There are a couple different ported enclosure designs suggested by Adire, but none for sealed...they list an enclosure VOLUME for sealed, but they give no dimensions...that's why I didn't think the shape of the enclosure mattered, only the volume...
Another clue to your problem...not all drivers are designed to fit into both sealed AND ported enclosures! Cone weight, suspension, motor (linear) parameters are different. Adire designed that driver therefore for a vented (4th order) alignment only. There are box size calculators on the net.
I would believe that to be the case if 1) they didn't list any enclosure volumes for sealed enclosures (which they do), or 2) they would publish some type of a statement saying that this driver is only designed for ported enclosures (which I have not seen)...also, if they were only for ported applications, I doubt this would sound good... http://www.n6eaj.com/diyaudio/sonotube/
 
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Ignore my last post. I was in the process of editing it after reading the Adire spec sheet when the BITOG editor timed out and wouldn't allow my changes. I include them below:
Originally Posted By: grampi
There are a couple different ported enclosure designs suggested by Adire, but none for sealed...they list an enclosure VOLUME for sealed, but they give no dimensions...that's why I didn't think the shape of the enclosure mattered, only the volume...
Remembering you posted some specs, I went back to have a look: Vas is huge at 317 liters. This means a large box to start with, but the bigger the better. Very low Fs of 19Hz, which is fine. Large dia. VC and long linear throw of 33mm. None of the various alignments give a spec for ripple in the passband. For a 2nd order alignment, you really want #3 which means a 6 cu. ft box in your living room, stuffed with 4 pounds of fluff....that's alot of fluff.... The dB figure as quoted is only attained when 750W is applied! In HT though, we don't listen to sine waves as music/dialogue/tracks aren't at all the same. Also note the "assumed" dB gain levels that are figured into the results. Thus these figures need to be taken with half-a-grain of salt: What size cabin? What shape room? No spec for that. In the vented alignments, the required box volume is very large indeed as is the multiple vent dia. and length. And remember, when using a driver of this size in any alignment sealed or vented, the box volume must be increased to account for the room taken up by both the driver and vent volume. Volume must also be accounted for any lost due to bracing as well. Due to their higher order, they are more easily mis-aligned and as such, need to be carefully tuned in order to obtain the desired results. This means measuring equipment. A good book to begin with is Ray Alden's Speaker Building 201. May still be in print or you can borrow it from a library. If your local library doesn't have it, ask them to borrow it from another library that does. Libraries do this all the time.
 

grampi

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Originally Posted By: sleddriver
Ignore my last post. I was in the process of editing it after reading the Adire spec sheet when the BITOG editor timed out and wouldn't allow my changes. I include them below:
Originally Posted By: grampi
There are a couple different ported enclosure designs suggested by Adire, but none for sealed...they list an enclosure VOLUME for sealed, but they give no dimensions...that's why I didn't think the shape of the enclosure mattered, only the volume...
Remembering you posted some specs, I went back to have a look: Vas is huge at 317 liters. This means a large box to start with, but the bigger the better. Very low Fs of 19Hz, which is fine. Large dia. VC and long linear throw of 33mm. None of the various alignments give a spec for ripple in the passband. For a 2nd order alignment, you really want #3 which means a 6 cu. ft box in your living room, stuffed with 4 pounds of fluff....that's alot of fluff.... The dB figure as quoted is only attained when 750W is applied! In HT though, we don't listen to sine waves as music/dialogue/tracks aren't at all the same. Also note the "assumed" dB gain levels that are figured into the results. Thus these figures need to be taken with half-a-grain of salt: What size cabin? What shape room? No spec for that. In the vented alignments, the required box volume is very large indeed as is the multiple vent dia. and length. And remember, when using a driver of this size in any alignment sealed or vented, the box volume must be increased to account for the room taken up by both the driver and vent volume. Volume must also be accounted for any lost due to bracing as well. Due to their higher order, they are more easily mis-aligned and as such, need to be carefully tuned in order to obtain the desired results. This means measuring equipment. A good book to begin with is Ray Alden's Speaker Building 201. May still be in print or you can borrow it from a library. If your local library doesn't have it, ask them to borrow it from another library that does. Libraries do this all the time.
My enclosure is 4.7 cubes...the net is probably closer to 4 cubes, figuring for internal bracing and speaker displacement....would I need measuring equipment if I bought a manufactured sub? Building a decent performing sealed enclosure can't be this difficult...
 
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Originally Posted By: grampi
....would I need measuring equipment if I bought a manufactured sub? Building a decent performing sealed enclosure can't be this difficult...
Ideally, you would use REW to measure your response and it will be very helpful in figuring out the problem. It could just be a peak in your room. That could be fixed by changing the placement, or you could use EQ (DSP) to level it out. Since you need an amp anyways, the iNukes are available with built in DSP that can be useful. Parts Express is great about returns, so if you get an amp and just can't get your desired results from your setup, you can always return it and go with a prebuilt version. However, if it is a peak caused by the placement in your room, the prebuilt sub will have the same problem. Sent you a PM on AVS.
 

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Originally Posted By: mjoekingz28
Originally Posted By: grampi
This one looks like a better choice than the plate amp: http://www.parts-express.com/crown-xls-1002-drivecore-2-power-amplifier-2-x-350w-at-4-ohms--245-507 I could bridge it into one voice coil, that would give me 700 watts...it's a bit less expensive too...I also noticed my 4 cft sealed enclosure can be ported...adds 3db which is like doubling the power...
You said you were going to bridge one voice coil. I'm out. You guys are too smart..
I did, but that isn't going to work...I would either have to run the amp in stereo (left and right channel into each VC), or parallel the VCs and run the amp in mono... And there may be some smart ones in here, but one of them ain't me....I can't even build a simple sealed enclosure!
 

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Originally Posted By: Zeus33
Originally Posted By: grampi
....would I need measuring equipment if I bought a manufactured sub? Building a decent performing sealed enclosure can't be this difficult...
Ideally, you would use REW to measure your response and it will be very helpful in figuring out the problem. It could just be a peak in your room. That could be fixed by changing the placement, or you could use EQ (DSP) to level it out. Since you need an amp anyways, the iNukes are available with built in DSP that can be useful. Parts Express is great about returns, so if you get an amp and just can't get your desired results from your setup, you can always return it and go with a prebuilt version. However, if it is a peak caused by the placement in your room, the prebuilt sub will have the same problem. Sent you a PM on AVS.
I agree, and I think the Crown amps have DSP as well...
 
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Originally Posted By: grampi
...Building a decent performing sealed enclosure can't be this difficult...
Remember, I previously recommended Thor as a thoroughly-worked-out-sealed-design. Linkwitz has already done all of the design work. To play, you've got to pay!
 

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Originally Posted By: grampi
Originally Posted By: mjoekingz28
Originally Posted By: grampi
This one looks like a better choice than the plate amp: http://www.parts-express.com/crown-xls-1002-drivecore-2-power-amplifier-2-x-350w-at-4-ohms--245-507 I could bridge it into one voice coil, that would give me 700 watts...it's a bit less expensive too...I also noticed my 4 cft sealed enclosure can be ported...adds 3db which is like doubling the power...
You said you were going to bridge one voice coil. I'm out. You guys are too smart..
I did, but that isn't going to work...I would either have to run the amp in stereo (left and right channel into each VC), or parallel the VCs and run the amp in mono... And there may be some smart ones in here, but one of them ain't me....I can't even build a simple sealed enclosure!
The amp doesn't have the option of being bridged into mono? You only need, and want, two wires coming from the amp. It is how you wire the voice coils that dictates whether you are going to be at 8ohms or 2ohms (the coils are 4 ohms, correct?) My Bravox has 2ohm coils, so I have it wired in series for a 4ohm load, as that's all the amp will handle.
 

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Just looked at the Crown amp you linked, it lists a minimum load of 4ohms bridged, so you'd have to wire the sub for 8. The 1002, which I assume is the model you want, lists an output of 700W at 8ohms bridged, so I think it would be ideal.
 

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Originally Posted By: OVERKILL
Just looked at the Crown amp you linked, it lists a minimum load of 4ohms bridged, so you'd have to wire the sub for 8. The 1002, which I assume is the model you want, lists an output of 700W at 8ohms bridged, so I think it would be ideal.
Based on the Tempest having two 8ohm VCs, and the impedance requirements of the amp, I'm limited to connecting to each VC in stereo (214 wrms X 2 into 8ohms), or paralleling the VCs and connecting in mono, but since the sub's max power handling is 750 wrms, this amp would be pushing too much power in this configuration (1100 wrms X 1 into 4ohms). If the sub had two 4ohm VCs, or if I used two of these subs, then I could mono it into 4ohms...I think running it in stereo should be enough power...
 

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Originally Posted By: JHZR2
Originally Posted By: grampi
I'm looking for one under $1000. After quite a bit of research, this is at the top of my list... http://hsuresearch.com/products/vtf-3mk5HP.html What do you have and/or are there better ones in this price range?
Hsu is what I have, and it works great. Have had it for nearly 10 years...
Let me ask you a question...when you bought this sub, did you have to use a mic and some type of program to find out where it needed to be placed in the room, and how it needed to be equalized, or did you pretty much just stick in an open spot in your listening area and set up the sound by ear?
 

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Originally Posted By: grampi
Originally Posted By: OVERKILL
Just looked at the Crown amp you linked, it lists a minimum load of 4ohms bridged, so you'd have to wire the sub for 8. The 1002, which I assume is the model you want, lists an output of 700W at 8ohms bridged, so I think it would be ideal.
Based on the Tempest having two 8ohm VCs, and the impedance requirements of the amp, I'm limited to connecting to each VC in stereo (214 wrms X 2 into 8ohms), or paralleling the VCs and connecting in mono, but since the sub's max power handling is 750 wrms, this amp would be pushing too much power in this configuration (1100 wrms X 1 into 4ohms). If the sub had two 4ohm VCs, or if I used two of these subs, then I could mono it into 4ohms...I think running it in stereo should be enough power...
If it has two 8ohm coils, then you run it in parallel to provide a 4ohm load. The amp is not going to nuke the sub unless you over-drive it, which is surprisingly hard to do.
 

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Originally Posted By: sleddriver
Originally Posted By: grampi
...Building a decent performing sealed enclosure can't be this difficult...
Remember, I previously recommended Thor as a thoroughly-worked-out-sealed-design. Linkwitz has already done all of the design work. To play, you've got to pay!
I've looked at that sight twice now and each time I do, I swear I can smell smoke coming from my head! All of the formulas and equations, reminds of when I was taking algebra for my degree. It's way to in depth for me...I need to operate much more lamen-like...thanks to zeus33, he found these... https://web.archive.org/web/20040605184846/http://www.adireaudio.com/Files/SealedTempestApplications.PDF My enclosure is almost identical in size and shape to the mid q design...while I'm not ruling out that it still could be an alignment problem, I don't think STARTING with building another enclosure is my best move...my first step has already been determined, I can't do anything without a working amp....once I get the amp, then I can start moving the sub around the listening area to see if it's a location problem. I may even use a mic and a computer program to aid with this. If it ends up being a problem with this enclosure, I would probably opt to build the low q design...
 
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Pole/zero analysis is important as their placement is critical. Further, he plots the results and the measurements. The point being this is critical for a well-thought-out design. If it's over your head, OK. All you need to do is just buy the driver and build the box to spec. An active filter & amp will also be necessary as every sub needs that. Re: Adire pdf. You didn't have this info when you bought the driver? They've provided you with all of the necessary dimensions for a sealed alignment, including bracing. Why reinvent the wheel when Adire has their own construction details? Re: Power requirements. Before buying a monster amp, you should read the app. note you linked to. In it you'll find this: I think you're making the mistake of getting a big amp due to the drivers 750W max power rating. That's not necessary, nor recommended, even by Adire. He clearly states so. 100W/ch is fine. Save your money. Finally, the amp doesn't "push" power into the driver. The later is the load and it pulls current as needed from the output stage, which is essentially a constant voltage power source. The freq-dependant impedance of the load is constantly changing, therefore so is the amount of current draw. A sub only operates over a few octaves anyway, from 20 - 80Hz is two octaves. At higher freq. it needs to be rolled off at either 12 or 18 dB/octave. That's the filters job. Likewise the loudspeakers are spared having to reproduce these two lowest octaves, which greatly reduces their distorsion and improves their power handling abilities.
 

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^Very valuable info provided there thumbsup I generally err on the side of having too much rather than too little in terms of driving power. I listen to loud, often bass-heavy music, and as such, have found the limits of a few different amps, including my present one for driving the sub. I had to dial out some of the gain in my Denon receiver for the sub in order to stop it from going thermal. I've used a PA poweramp to drive my sub with a similar power rating to that Crown unit (Yorkville), but the heat it put off, as well as the inability to elegantly trigger its power on/off, caused me to go with something that integrated into my system a bit better. I'm currently using a SpeakerCraft SC2-100, which has remote trigger and an output of 400W RMS bridged @ 8ohms, or 220W/channel unbridged at 4Ohms.
 
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Thanks OK! Power requirements can be calculated. Linkwitz crunches through the numbers if you're interested and the math is straight forward. I agree to err on the higher side but within limits. After all "a man's got to know his limitations". As I previously stated, more small subs are far better than one huge one. The custom stereo MOSFET amp I built decades ago now will put out about 120W RMS continuous if the power supply is up to it. Going higher is a problem with a single supply because the breakdown voltage at the input differential pair is around 80Vdc. Using a dual supply with a regulator on the input stage while allowing the driver & output stage to draw a higher voltage is the next step. However, it won't all fit within the existing aluminum chassis I built! I have another MOSFET amp that needs refurbing. I think it's an old Sherwood. It weighs about 75 pounds and is rated ____ can't remember.....150 - 175W RMS/ch. HUGE, HEAVY xnsfrmr! It would make a great bass amp for my bi-amplified system. Fortunately it is still working fine. Merry Christmas! cheers
 

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Originally Posted By: sleddriver
Pole/zero analysis is important as their placement is critical. Further, he plots the results and the measurements. The point being this is critical for a well-thought-out design. If it's over your head, OK. All you need to do is just buy the driver and build the box to spec. An active filter & amp will also be necessary as every sub needs that. Re: Adire pdf. You didn't have this info when you bought the driver? They've provided you with all of the necessary dimensions for a sealed alignment, including bracing. Why reinvent the wheel when Adire has their own construction details? Re: Power requirements. Before buying a monster amp, you should read the app. note you linked to. In it you'll find this: I think you're making the mistake of getting a big amp due to the drivers 750W max power rating. That's not necessary, nor recommended, even by Adire. He clearly states so. 100W/ch is fine. Save your money. Finally, the amp doesn't "push" power into the driver. The later is the load and it pulls current as needed from the output stage, which is essentially a constant voltage power source. The freq-dependant impedance of the load is constantly changing, therefore so is the amount of current draw. A sub only operates over a few octaves anyway, from 20 - 80Hz is two octaves. At higher freq. it needs to be rolled off at either 12 or 18 dB/octave. That's the filters job. Likewise the loudspeakers are spared having to reproduce these two lowest octaves, which greatly reduces their distorsion and improves their power handling abilities.
No, there were none of these enclosure designs included with the driver. The only thing I ever saw from Adire was the 3 different enclosure volumes for low, mid, and high q enclosures, which is why I thought that only the amount of volume was important and not the shape. If I end up having to build another enclosure, I will build Adire's high q design (or whichever one was the biggest enclosure). As far as the amp goes, each VC will only be getting 215 watts....though the amp is capable of producing a lot more power than that, voice coil impedances and load requirements for the amp prohibits connecting it in such a way that would unleash all of that power...so the amp will have easy duty...and my AVR already has a low pass filter on the LFE output set at 80 hz (I'm sure most AVRs have them)...I'm not sure what the roll of rate is, but it's probably at least 12 db per octave...the amp has one too, I can use either one I choose...
 
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Originally Posted By: sleddriver
Thanks OK! Power requirements can be calculated. Linkwitz crunches through the numbers if you're interested and the math is straight forward. I agree to err on the higher side but within limits. After all "a man's got to know his limitations". As I previously stated, more small subs are far better than one huge one. The custom stereo MOSFET amp I built decades ago now will put out about 120W RMS continuous if the power supply is up to it. Going higher is a problem with a single supply because the breakdown voltage at the input differential pair is around 80Vdc. Using a dual supply with a regulator on the input stage while allowing the driver & output stage to draw a higher voltage is the next step. However, it won't all fit within the existing aluminum chassis I built! I have another MOSFET amp that needs refurbing. I think it's an old Sherwood. It weighs about 75 pounds and is rated ____ can't remember.....150 - 175W RMS/ch. HUGE, HEAVY xnsfrmr! It would make a great bass amp for my bi-amplified system. Fortunately it is still working fine. Merry Christmas! cheers
Merry Christmas! cheers BTW, my aunt had 4x (IIRC) McIntosh power amps that came out of a huge home theatre (cinema) I think they were "rated" for 150W RMS. they had to weigh similar to your Sherwood. I always thought they would have worked well driving a sub. The issue with my setup, not to go off on a tangent, is I'm using a car audio sub with an obscene power handling rating. My buddy won the IASCA Nationals with this sub in a Mercury Cougar years back. Two of them, in another box, he won SQ. He had a couple of huge amps bridged down to 0.5ohms feeding the pair of them. I remember one of the amps blowing up and it was rather impressive, LOL! I think that setup was 4K watts? Might have been more. Anyways, the sub is ridiculous, and so I've sort of settled on just feeding it with something adequate for my listening needs rather than trying to match its rating. I've thus far concluded that the SpeakerCraft isn't quite big enough, but is the right "style". If you've got any recommendations on something that can handle 4ohms bridged, I'm all ears grin Edit: Would definitely be interested in those calculations smile
 
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