Re: 2 boxes per channel
I assume you mean in a prosound app as I used a well abused USA900 to drive two 0.89 ohm Contrabass sub kits (one/channel) for months in a HIFI/HT app that included literally busting up my house with >120 dB sustained low B pipe organ and movie special effects.
GM
wg_ski said:
I assume you mean in a prosound app as I used a well abused USA900 to drive two 0.89 ohm Contrabass sub kits (one/channel) for months in a HIFI/HT app that included literally busting up my house with >120 dB sustained low B pipe organ and movie special effects.
GM
Yes, I would calculate this if I knew how, fortunately it's already been done. According to a seasoned user of LABs: two cabinets in parallel (four 6 ohm speakers) comes to 1.5 ohms and when you add horn loading (esp four labhorns together) and other factors, it runs around 3.5 ohms and up depending on conditions. (The guy was going by a readout from the amp when they were running.)
You know, I need to find a thread about X-TROs that can help me understand how the wiring and amps are set up.
I would say if there's a pro sound person in/near Atlanta that needs some X-TROs, I would build them a very nice looking pair or two for free labor (minus cost of electronics) in trade for hands-on education about how to wire them and run them...
Maybe I could start a thread like this? I wonder what section I should start it under?
I would say if there's a pro sound person in/near Atlanta that needs some X-TROs, I would build them a very nice looking pair or two for free labor (minus cost of electronics) in trade for hands-on education about how to wire them and run them...
Maybe I could start a thread like this? I wonder what section I should start it under?
Re: Re: Re: 2 boxes per channel
Agreed compared to prosound, but in my case it was a 2 ohm rated amp driving a < 1 ohm servo motor, which is well outside the parameters of a typical HT. Regardless, I wasn't questioning that they didn't work for you or that there's better performing amps available, just that I don't believe it's as poor a quality amp series as you implied.
GM
wg_ski said:
Agreed compared to prosound, but in my case it was a 2 ohm rated amp driving a < 1 ohm servo motor, which is well outside the parameters of a typical HT. Regardless, I wasn't questioning that they didn't work for you or that there's better performing amps available, just that I don't believe it's as poor a quality amp series as you implied.
GM
It's a top designed by the guy who did the 'punisher' horn. Details can be found on the speakerplans site.
Rob.
Xtro plans
Got the dvd of the film btw...
Rob.
Xtro plans
Got the dvd of the film btw...
GM said:
I first saw it when I was around 10 years old. Scared the hell out of me. I've carried a soft spot for it ever since. It's a really strange plot which is kind of interesting. The special 'effects' let it down but it's got some original themes and ideas. Not very well acted. Spent some time on the UK's 'video nasty' list in the 80's. I also own an original vhs copy from way back.
If you like leftfield / cult horror give it a go.
Rob.
boukisan, you might already have this covered but remember that if you build the XTRO cabs you will need some decent processing. (Read- not Behr*****) Might be fine for HT use but they just don't hold up.
Get a used XTA or one of the new units by Xilica. (Just make sure it works out of the box) The BSS Omnidrives are good too.
Get a used XTA or one of the new units by Xilica. (Just make sure it works out of the box) The BSS Omnidrives are good too.
Cooling plug info
The 12Pi hornsub has the cooling plug and plate in the front chamber on one side and the rear chamber on the other. This is a result of configuring the two woofers in push-pull drive. The cooling plug and the push-pull drive are the two main features that set it apart from other basshorn subwoofers.
In the prototype, I had cooling plugs machined on a lathe. I simply removed the paint from the inside of the pole piece on each woofer and inserted the plugs. Conductive grease was put on the plug before insertion, and also on the plate where it attaches to the plug. So the interfaces are covered with conductive grease.
On later models, we shifted to having the motors machined. The vent in the pole piece does not have uniform internal diameter, and it changes between production runs. So we machine it now just enough to provide a uniform surface. Each woofer coming from us has the same pole piece vent diameter. This allows us to stock one cooling plug size and ensures better contact between cooling plug and pole piece.
You can do a DIY version of the process with a drill press. A 31mm drill bit is 1.220”, 1-15/64” is 1.234”, 31.5mm is 1.240” and 1-1/4 is 1.250”. Pick the size that takes off the least amount and machine both the pole piece and cooling plug to fit. Machine the pole piece to fit +0.002/ -0.000.
You might be somewhat reluctant to do this yourself, but it is actually pretty safe. The magnet tends to catch the debris for you, making it easy to remove. We haven't had any problems at all with contamination of the gap. Just use caution and work slowly and carefully.
boukisan said:
The 12Pi hornsub has the cooling plug and plate in the front chamber on one side and the rear chamber on the other. This is a result of configuring the two woofers in push-pull drive. The cooling plug and the push-pull drive are the two main features that set it apart from other basshorn subwoofers.
In the prototype, I had cooling plugs machined on a lathe. I simply removed the paint from the inside of the pole piece on each woofer and inserted the plugs. Conductive grease was put on the plug before insertion, and also on the plate where it attaches to the plug. So the interfaces are covered with conductive grease.
On later models, we shifted to having the motors machined. The vent in the pole piece does not have uniform internal diameter, and it changes between production runs. So we machine it now just enough to provide a uniform surface. Each woofer coming from us has the same pole piece vent diameter. This allows us to stock one cooling plug size and ensures better contact between cooling plug and pole piece.
You can do a DIY version of the process with a drill press. A 31mm drill bit is 1.220”, 1-15/64” is 1.234”, 31.5mm is 1.240” and 1-1/4 is 1.250”. Pick the size that takes off the least amount and machine both the pole piece and cooling plug to fit. Machine the pole piece to fit +0.002/ -0.000.
You might be somewhat reluctant to do this yourself, but it is actually pretty safe. The magnet tends to catch the debris for you, making it easy to remove. We haven't had any problems at all with contamination of the gap. Just use caution and work slowly and carefully.
My opinion about Beh****** in general is you get what you pay for. The DCX and DEQ units have had their share of issues, although they have addressed them with newer units. We have had a number of thier processing products through the doors at work and they just don't hold up well outside of a living room or studio. The exception in my opinion is their cable tester ct100 and the ADA8000- probably the best ADAT to Analog convertor for the money. Out of about 50 we've had 2 fail.
YMMV
YMMV
DCX2496 is great, it provides more processing power than other filters costing 10 times more. The phase shifters (and the ability to use up to 9 parametric EQs per channel) are probably the most useful features to achieve proper acoustical summing with horns, and you won't find them in much more expensive competitor models from reputable manufacturers (that in my opinion are completely useless).
Considering the price of DCX2496, you could buy two or three spare units just in case one fails, and you would still end up spending much less money and getting better processing than with filters from reputable brands.
Considering the price of DCX2496, you could buy two or three spare units just in case one fails, and you would still end up spending much less money and getting better processing than with filters from reputable brands.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.