2 'lesser quality' subs = 1 'good' sub? (1 Viewer)

[Mike Thomass]

btw, bondo is fantastic it appears

 

[Mike Thomass]

flux is mandatory for soldering? what kind?

 

[Mike Thomass]

rob, couple more things when you get some free time:


these are the drivers i have

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-310

apparently 8 ohms, and it says Re 6.3 ohms, which i dont know what that means


i was planning on buying the pioneer vsx-1020

http://www.pioneerelectronics.com/PUSA/Home/AV-Receivers/Pioneer+Receivers/VSX-1020-K


if you look at the specifications tab, it talks about ratings at 8 ohm and 6 ohm. how do i find out what range this thing can handle, or do i care? im trying to make sure the receiver can handle the speakers im building. so if i wire the 8 ohm drivers in parallel, thats a 4 ohm load on that channel, correct? will that be a problem for the vsx-1020? keep in mind i dont know what im talking about (a little knowledge is dangerous kinda thing).

 

[Robert_J]

1/2" polyfil is no where close to 1 pound per cubic foot. You have to stuff by the handful to get that much in the box. Just don't impede the air flow into the port....Really, you don't need that much. That enclosure was designed to work without stuffing. Go to Wal-Mart and get some open cell, egg crate foam (mattress pad) and cut it to fit the sides and behind each driver. That will absorb the higher frequencies of the rear wave and lessen the reflection.


Bondo is great about fixing any mistake. One of these days I'll get brave and fix the hail damage on my 15 year old car.


My solder has flux in it. Probably Radio Shack brand. I'll check the part number when I go through the garage next time.


Re is the measure of resistance. DC current is applied. Impedance is when an AC current (that's what makes the sound) is sent through the speaker. The impedance varies by frequency and the average is 8 ohms.


I'm a huge Pioneer fan. I'm sorry if I am repeating myself but I listen to a VSX-4800 every day during work. Bought from Wal-Mart in 1992. I've run nothing but Pioneer head units in my car since the 1980's with the exception of a Sony because I needed a shallow mounting depth in one car. My home theater receiver is a VSX-1014 and it does fine with 4 ohm speakers.


One thing about all of the speakers designed by Wayne J., they are easy on the amps. No wild impedance swings. His DHT design is probably the lowest impedance of all and that's what I need to finish building.

 

[Mike Thomass]

Originally Posted by Robert_J

1/2" polyfil is no where close to 1 pound per cubic foot. You have to stuff by the handful to get that much in the box. Just don't impede the air flow into the port....Really, you don't need that much. That enclosure was designed to work without stuffing. Go to Wal-Mart and get some open cell, egg crate foam (mattress pad) and cut it to fit the sides and behind each driver. That will absorb the higher frequencies of the rear wave and lessen the reflection.


Bondo is great about fixing any mistake. One of these days I'll get brave and fix the hail damage on my 15 year old car.


My solder has flux in it. Probably Radio Shack brand. I'll check the part number when I go through the garage next time.


Re is the measure of resistance. DC current is applied. Impedance is when an AC current (that's what makes the sound) is sent through the speaker. The impedance varies by frequency and the average is 8 ohms.


I'm a huge Pioneer fan. I'm sorry if I am repeating myself but I listen to a VSX-4800 every day during work. Bought from Wal-Mart in 1992. I've run nothing but Pioneer head units in my car since the 1980's with the exception of a Sony because I needed a shallow mounting depth in one car. My home theater receiver is a VSX-1014 and it does fine with 4 ohm speakers.


One thing about all of the speakers designed by Wayne J., they are easy on the amps. No wild impedance swings. His DHT design is probably the lowest impedance of all and that's what I need to finish building.

ok, well, i already have the solder and the polyfil. turns out the solder i have has flux in it as well. the parts express silver solder stuff. i didnt know they combined it (flux/solder)

as for the polyfil, i assume now it should be attached to the wall somehow and it doesnt really matter how much i put in there.

once i use up this polyfil, im going to go with some type of foam i think, seems easier.


as for pioneer, i wasnt worried about the brand, just wanted to be sure the 4ohm thing wouldnt be a problem.


im trying to decide where to put the crossovers in the cabinet. i want to just put them in the bottom and be done with it, but im sure if i do that and seal it up, something will be wrong with them. so how close can they be to the drivers without interfering? 6 inches? 12 inches? more?

 

[Robert_J]

My crossovers are about 4" from the drivers.


Someone made some bases for their D8 and mounted the crossover in the base. Turn the speaker over and there's the crossover on the bottom.


Just stuff some polyfil behind the 8" drivers and be done with it.

 

[gene c]

I'm afraid I'm going to throw a wrench into your plans. Sorry . The 1014 was a fine receiver (I had one a few years ago) but Pioneer watered down the amp section in the 10XX series starting with the 1019. The 1019 lost 10 lbs from the 1018 (35% of the 1018's weight). I'm not sure I'd try and run 4 ohm speakers with the 1020 without doing a bit more research. Try and find someone who is already doing it. I have a 94txh and ran five 4 ohm Swan Dulce's (gorgeous speakers, lousy center channel ) for a while and it didn't even work up a sweat. But the 94 is much, much stronger than the 1020. I'd give it a little more thought first. Maybe it could, but I'd be awfully nervous.


I know weight and power consumption aren't the end-all of a receivers power output but...:


1014) 34 lbs. Power consumption: 480 watts


1019) 19 lbs. 350 watts


1020) 22 lbs. 245 watts


Bench Test power output:


Elite 52tx (same as 1014) 115 wpc X 5


1017) 134 X 5


1019) 29 X 5


See a pattern?

 

[Mike Thomass]

Gene,

iirc, when I was looking at all the various brands and models, it they all seemed to have the same type of specs. So much whatever @8ohm. How would I determine which ones can handle two 4 ohm speakers comfortably?

 

[Robert_J]

You can go with an external amp if needed. Maybe adding a Behringer A-500 to run the D8's and use the receiver's amp section for all of the rest.

 

[Mike Thomass]

Originally Posted by Robert_J

You can go with an external amp if needed. Maybe adding a Behringer A-500 to run the D8's and use the receiver's amp section for all of the rest.

i would determine 'if needed' by running the setup and listening for problems?

 

[Mike Thomass]

im so frustrated right now.

i get stressed over trying to figure out how to install polyfil. imagine how stressed i am now trying to figure out what to do about this receiver situation.

external amp sounds like an easy fix (if one is required at all), but the amp is almost $200. For an extra $200, i should be able to find another receiver that can handle 4ohms with no questions asked, or no?

even if i have to resort to the external amp setup, i will need 2 external amps if i make another D8 for the center channel. now im looking at an extra $400. or i could make a smaller center channel i guess.

i have been looking at receivers for a good part of the day today, and i havent seen anything that mentions 4ohms, and i dont know how to read between the lines. fark!!!!!

 

[Mike Thomass]

Originally Posted by Robert_J

You can go with an external amp if needed. Maybe adding a Behringer A-500 to run the D8's and use the receiver's amp section for all of the rest.

what would happen to the tweeter in this case? would it get damaged somehow?

 

[Robert_J]

Using an external amp won't damage anything.


Just look on Ebay for an older amp. Ask in the receiver section here to see which amps will safely drive a 4 ohm load.


I chose my 1014 years ago because of postings here that it would easily drive a 4 ohm load even though it was only rated to drive 6 ohms. I just checked ebay and there are a bunch of new, old stock of Elite receivers.

 

[Mike Thomass]

Originally Posted by Robert_J

You can go with an external amp if needed. Maybe adding a Behringer A-500 to run the D8's and use the receiver's amp section for all of the rest.

Im assuming most receivers have 1 pre-amp output. So, if we come to the conclusion the 1020 needs an external amp to run the D8s, where are we getting the source signal from? Take the 1 pre-amp output and split it 3 ways? (one for the sub and two for the mains?) what about the center channel then? (assume a D8 center). Im assuming you cant run an amplified signal into an amplifier. That’s correct, right?


Side note, I spoke to pioneer tech support, guy said none of the pioneers should be run with 4ohm speakers. None. I said to him, 'not even your most expensive model', he said, 'well sure, the sc-09, but that’s it!' (sc-09 is $7000). Im not sure if he was just saying that to cover his ass or if he was saying it as truth. Probing him further, I asked him what would happen if I hooked up a 4ohm speaker to the 1020, would it blow up or would it slowly die or what? He said he cant be sure. It might die right away or it might slowly die over time.


On another side note, the first person I spoke to who was in the warranty group checked on my question, and she said 'you should be ok running a 4ohm speaker, but don’t go any lower!' I said, well, its not going to be exactly 4ohm all the time, might me a little more or a little less, so whats the deal? She said something irrelevant and said I should double check with tech support.

 

[Mike Thomass]

i was typing that reply in word, didnt see you replied already. ignore anything youve answered already robert. thanks!

 

[Mike Thomass]

im ready to toss the whole project off a bridge

 

[Robert_J]

I Googled pioneer vsx-1020 4 ohm speakers and found a lot of information. A lot of people run their Pioneer at 4 ohms without any problem. Just don't put anything on top of the receiver so the hot air can escape.

 

[Mike Thomass]

Originally Posted by Robert_J

I Googled pioneer vsx-1020 4 ohm speakers and found a lot of information. A lot of people run their Pioneer at 4 ohms without any problem. Just don't put anything on top of the receiver so the hot air can escape.

i did similar and didnt find anything that said it was a good idea. any chance you can link me to something saying they have no problems using 4ohm with the 1020?

currently im going over the returns from your exact search, and im still not seeing anything relevant

 

[Robert_J]

Some of the AVS posts said that 4 ohm was OK. I'd do it.

 

[gene c]

The 1020 doesn't have pre-outs.

Originally Posted by Mike Thomass

I just didn't want to burn up your new receiver with those 4 ohm speakers.


Many receivers that aren't certified for 4 ohm can drive them anyway, but I'm sure it would usually be the higher priced models. I just have my doubts about the 1020's ability to do so long term. The 1014, yes. The 1020, I don't know. They're packing an awfull lot of new things into these newer receivers and something has to give. Usually it's the amp section.


I'm not sure of any tell-tale signs that a particular receiver would work with 4 ohm speakers. I just look at all the data and let common sense take over. I might try it with the 1120 myself but I wouldn't feel comportable recommending it for someone else. The 1120 does have a better amplifier in it.


Maybe you should start another thread in the receivers forum. Pick a price point and most needed features. Refurbished or a good used one might be your best bet. As an example, someone on Audiogon has a 92txh for $350/best offer. I was eyeing that myself but picked up an Integra instead.


Onkyo has a few 4 ohm receivers, I think starting with the 7XX models. As I understand it, most 4 ohm receivers, when set to 4 ohms, simply reduce the power output to help protect it. I've often heard you should leave it at the 8 ohm setting anyway.


Anyway, finish the speakers first, then worry about the receiver.


Edit: If others at another forum are doing it then that's the kind of re-assurance I was hoping to find. But that still sounds like a lot to ask of that receiver.