Say I added a subwoofer to the mix...
I have 7 channel sound on my computer, which is where I will be using these speakers. If I hook up the Sophomores to the Green speaker output, can I then separatley hook up a subwoofer via the subwoofer output? (And is that a mono plug?)
Also, would I need a preamp? The sophomores are going to be driven by 2 x LM3886 with preamps. That's just because the board I ordered happened to have Op-Amp preamps.
Is it required that I use a preamp even if I am coming straight out of the subwoofer jack? It would make my life easier...
But whatever sounds the best...
Sorry for getting off topic. Thanks.
I have 7 channel sound on my computer, which is where I will be using these speakers. If I hook up the Sophomores to the Green speaker output, can I then separatley hook up a subwoofer via the subwoofer output? (And is that a mono plug?)
Also, would I need a preamp? The sophomores are going to be driven by 2 x LM3886 with preamps. That's just because the board I ordered happened to have Op-Amp preamps.
Is it required that I use a preamp even if I am coming straight out of the subwoofer jack? It would make my life easier...
But whatever sounds the best...
Sorry for getting off topic. Thanks.
The level from a sound card usually offers enough gain to get a 'typical' power amp going. Preamps also offer more control (knobs etc..) but the PC should probably offer all the control you need.
First off- what sub design? There are lots of them out there. Since you're using it at the PC, I have a 9" cube called the Triumph or Biumph (depending on which version) that will be small enough to make that easier to use.
The Madisound KG3100 would allow you to have the 3(2.1) channel amplified you are inquiring about without using the LM3886 boards.
Typically, PC plugs are stereo, but you can set the settings to 2.1, and not allow the center channel (typical in the same plug) to operate the output. Even if the signal is still presented, use a 3.5mm to dual RCA splitter, and leave the other disconnected.
Most PC's are used *AS* preamps, and a plate-amp would suffice for the sub.
Later,
Wolf
The Madisound KG3100 would allow you to have the 3(2.1) channel amplified you are inquiring about without using the LM3886 boards.
Typically, PC plugs are stereo, but you can set the settings to 2.1, and not allow the center channel (typical in the same plug) to operate the output. Even if the signal is still presented, use a 3.5mm to dual RCA splitter, and leave the other disconnected.
Most PC's are used *AS* preamps, and a plate-amp would suffice for the sub.
Later,
Wolf
Okay, so no preamp would most likely work. Cool...
Sub design. I really don't know. =(. I honestly love the sound of these HiVi M series woofers. I'm not sure if an M8a would be applicable as a stand alone subwoofer. Maybe a HiVi D8G/D8.8+?
As you guys might be able to tell, I don't have a lot of experience...
Why can't I just get a woofer, a box the size the manufacturer recommended, an amp powerful enough to drive it, and like an 80Hz low pass filter?
Would that not work?
Thanks for all of the help. I appreciate your patience with someone like me...
Sub design. I really don't know. =(. I honestly love the sound of these HiVi M series woofers. I'm not sure if an M8a would be applicable as a stand alone subwoofer. Maybe a HiVi D8G/D8.8+?
As you guys might be able to tell, I don't have a lot of experience...
Why can't I just get a woofer, a box the size the manufacturer recommended, an amp powerful enough to drive it, and like an 80Hz low pass filter?
Would that not work?
Thanks for all of the help. I appreciate your patience with someone like me...
The M8 will hit about 30 Hz in a 34 ltr cab, but it really isn't a sub. The D/DG series are the same way- mostly woofers.
If you want a smaller sub, TB has a few that would be appropriate.
As to the reomended alignments- they don't take everything into account, just kinda find the optimal textbook alignment for the driver. Usually these are more for output than extension, etc. You have Hoffman's iron law, so you pick 2 of 3:
*low extension
*high sensitivity
*small box
While what you propose would work, it may not be the best result for any driver.
Later,
Wolf
If you want a smaller sub, TB has a few that would be appropriate.
As to the reomended alignments- they don't take everything into account, just kinda find the optimal textbook alignment for the driver. Usually these are more for output than extension, etc. You have Hoffman's iron law, so you pick 2 of 3:
*low extension
*high sensitivity
*small box
While what you propose would work, it may not be the best result for any driver.
Later,
Wolf
Thanks wolf. I don't really care about box size as long as it's not 3ft cubed. I'd rather have whatever sounds best.
You say there is a textbook formula? What is it? I'd like to use it!
You say there is a textbook formula? What is it? I'd like to use it!
If you like it, then great. I'm using some midwoofers as subs in one of my systems, but you need to make sure they can move enough air for you. Going down to 20Hz is not mandatory although it is better. A good clean bass down to 50Hz is still good.
I'm not a basshead, and although my Sophomores aren't even constructed yet, I'm thinking that they are going to have difficulty below 70Hz. So I'd like a sub/woofer that can do clean 40-70Hz maybe.
What the deal on Daytons? Are they any good? I've seen some of their amps and they are really shoddy...but they were also cheap.
And this is being used with my computer so they aren't going to be full cranked. Maybe 30% power typically. I don't need earth-rattling bass, but I just don't want to miss the lower notes. Rock bass guitar is around 50-60Hz I believe. It would stink to just miss a whole instrument.
You're right. The M8a has a relatively small Xmax. Around 6mm I believe. Ahh! Maybe I should get these sophomores figured out before I try making my head spin even more!
What the deal on Daytons? Are they any good? I've seen some of their amps and they are really shoddy...but they were also cheap.
And this is being used with my computer so they aren't going to be full cranked. Maybe 30% power typically. I don't need earth-rattling bass, but I just don't want to miss the lower notes. Rock bass guitar is around 50-60Hz I believe. It would stink to just miss a whole instrument.
You're right. The M8a has a relatively small Xmax. Around 6mm I believe. Ahh! Maybe I should get these sophomores figured out before I try making my head spin even more!
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'Sophomore' F3 = ~55 Hz, so you may be surprised! I know they can do that. 😀
You finish these up first- then see if you still want one. Closer proximity at the computer means you may get lower response than further away as well.
The Dayton amps are not that shoddy for the whole line. I wouldn't use a DT100a or T-amp, but the plates of the 70W, 100W, and the BASH 300 and 500W I know are good values.
Later,
Wolf
You finish these up first- then see if you still want one. Closer proximity at the computer means you may get lower response than further away as well.
The Dayton amps are not that shoddy for the whole line. I wouldn't use a DT100a or T-amp, but the plates of the 70W, 100W, and the BASH 300 and 500W I know are good values.
Later,
Wolf
Yeah you're right. I'm giving myself more things to do...as usual.
I'm going out to get the MDF for the speaker cabinets in about 10 minutes. I'll just forget about the sub for now.
However, for future reference, I'd like to know if this would work. I bought two amplifier boards for my amp originally, so I have a spare LM4780 PCB that can be bridged. I'd need a mono input then...So I'd use a stereo to mono summing circuit. Would it have impedance issues? Crosstalk? Anything?
Thanks a lot.
Hopefully, the next time you hear from me is with some completed Sophomores. =D
I'm going out to get the MDF for the speaker cabinets in about 10 minutes. I'll just forget about the sub for now.
However, for future reference, I'd like to know if this would work. I bought two amplifier boards for my amp originally, so I have a spare LM4780 PCB that can be bridged. I'd need a mono input then...So I'd use a stereo to mono summing circuit. Would it have impedance issues? Crosstalk? Anything?
Thanks a lot.
Hopefully, the next time you hear from me is with some completed Sophomores. =D
Attachments
Are you sure about that? I thought you'd just invert an input. I'm not all up on bridged amps... If you want a combiner circuit though- yes- that will work.
BTW- screws into MDF edges is not a good idea. It will split and be destroyed. Most builders use brad nailers, or biscuits; or even just glue and butt joints. I used biscuits and butts on mine, with glue and clamps.
If you have any Q's along the way, feel free to ask!
Later,
Wolf
BTW- screws into MDF edges is not a good idea. It will split and be destroyed. Most builders use brad nailers, or biscuits; or even just glue and butt joints. I used biscuits and butts on mine, with glue and clamps.
If you have any Q's along the way, feel free to ask!
Later,
Wolf
Oh I wasn't aware of this inverting of an input thing...What do you mean?
Re: MDF
I'm actually quite handy with MDF. I've been building MDF shelves for years so...hopefully I won't screw anything up there....No pun intended. 😀
Thanks as always.
Re: MDF
I'm actually quite handy with MDF. I've been building MDF shelves for years so...hopefully I won't screw anything up there....No pun intended. 😀
Thanks as always.
Since it's the 4780 Kit you bought, there are 3 ways you can run that chip; 2 channel, paralleled, and bridged.
Bridged normally involves inverting one input:
Bridged and paralleled amplifiers - Wikipedia, the free encyclopedia
Later,
Wolf
Bridged normally involves inverting one input:
Bridged and paralleled amplifiers - Wikipedia, the free encyclopedia
Later,
Wolf
Heres the board: LM4780 stereo/parallel power amplifier PCB ! - eBay (item 320407281063 end time Mar-25-11 04:20:54 PDT)
It says only stereo and parallel. I got bridged and parallel mixed up...Sorry. It doesn't appear to have a bridged option. Not sure if LM4780 can do that? I think I'll just get these sophomores done first. I'll probably need a bigger transformer now too. 25V @ 625VA. I was originally going for a 25V @ 330VA for 2 x LM3886.
Maybe you still can use bridged, but seeing that there is no preamp on that board, I was also considering something like this: Subwoofer (12HZ-48HZ)+(28HZ-112HZ) preamplifier board - eBay (item 190511834547 end time Mar-20-11 08:06:08 PDT)
If I am looking at the pictures correctly, it takes two channels preamps them as well as puts it into one mono channel and gives some sort of control over the frequencies/loudness...which I might need.
Looks interesting to me...I don't know about you guys.
It says only stereo and parallel. I got bridged and parallel mixed up...Sorry. It doesn't appear to have a bridged option. Not sure if LM4780 can do that? I think I'll just get these sophomores done first. I'll probably need a bigger transformer now too. 25V @ 625VA. I was originally going for a 25V @ 330VA for 2 x LM3886.
Maybe you still can use bridged, but seeing that there is no preamp on that board, I was also considering something like this: Subwoofer (12HZ-48HZ)+(28HZ-112HZ) preamplifier board - eBay (item 190511834547 end time Mar-20-11 08:06:08 PDT)
If I am looking at the pictures correctly, it takes two channels preamps them as well as puts it into one mono channel and gives some sort of control over the frequencies/loudness...which I might need.
Looks interesting to me...I don't know about you guys.
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I would keep the amplifiers single and separate until/unless I could see the need to bridge them. I am seeing the setup process in stages here, where it could pay to keep things simple during the initial setup. Getting the correct max power by bridging or whatever is more of a 'tweaking' excercise for later unless you designed it all that way from the start.
That board on ebay looks like a great setup tool. Anything to help me perform the most tweaking in the least time gives good results in my book. Later I'd probably work out where I prefer the settings and find a way to replace it with something more permanent, but this is only my opinion. The 5532 op-amps are not bad.
That board on ebay looks like a great setup tool. Anything to help me perform the most tweaking in the least time gives good results in my book. Later I'd probably work out where I prefer the settings and find a way to replace it with something more permanent, but this is only my opinion. The 5532 op-amps are not bad.
I'm personally liking the preamp board because it may help me correct the errors I may make while trying to put together a sub box. Again, I think I'll just get the sophomores over with first. I'd like to hear them first...
However, since I do like to watch movies and play games, some true deep bass really means a lot.
Thanks.
However, since I do like to watch movies and play games, some true deep bass really means a lot.
Thanks.
Seems like shipping from China is slower than usual. I would have started work on the whole project this weekend, however, the majority of the boards I ordered are still not in. I ordered them around 3 weeks ago....
Anyway, I'm still interested in this subwoofer thing, and I have been looking around, mostly on parts-express. It seems that this woofer is probably the best value, and quality-wise, doesn't seem all that shabby. Rubber surrounds, Kevlar reinforced cone etc.
Dayton Audio DCS205-4 8" Classic Subwoofer 4 Ohm
I've looked around for projects but have found very little.
Can anyone give me any guidance? Have any ideas? How about this for a low-pass filter? 80 Hz Low Pass 4 Ohm Crossover.
Could I replicate my own with perhaps air-coils and better quality capacitor? (Same values).
To port, or not to port? Enclosure size?
Gahh...so much work.
Thanks for any input you may have.
-TheLaw
Anyway, I'm still interested in this subwoofer thing, and I have been looking around, mostly on parts-express. It seems that this woofer is probably the best value, and quality-wise, doesn't seem all that shabby. Rubber surrounds, Kevlar reinforced cone etc.
Dayton Audio DCS205-4 8" Classic Subwoofer 4 Ohm
I've looked around for projects but have found very little.
Can anyone give me any guidance? Have any ideas? How about this for a low-pass filter? 80 Hz Low Pass 4 Ohm Crossover.
Could I replicate my own with perhaps air-coils and better quality capacitor? (Same values).
To port, or not to port? Enclosure size?
Gahh...so much work.
Thanks for any input you may have.
-TheLaw
It looks to be a decent subwoofer. According to the Thiele/Small parameters, yes you should indeed port that speaker. As far as what enclosure volume to use, I cannot tell you I do not have any modeling software. But you can get some if you look around.
In my opinion, PASSIVE Low Pass filters (crossover) for subwoofers are horrific. A passive crossover of that type is designed to work with a constant impedance. However the impedance of a subwoofer is anything but constant/flat! In fact with a ported speaker you get two gigantic humps in the impedance at the box/woofer tuning frequencies. Not to mention that losses are considerable, just because the component sizes have to be very large. True, you can do better by buying higher quality components, but the performance to cost ratio is poor.
Most separate subwoofers are given their own amplifier, either internal or external and they usually have an active electronic filter (crossover) built in specifically for subwoofer use. Or you use a home theater receiver that has a subwoofer output etc. What you need is a "plate" amp.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-784
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Hmm....Well I'm just looking for a little bit of bass. Not necessarily audiophile standards. I am using a separate amplifier for the subwoofer. Bridged LM4780.
The two satellites are being run off of 2x LM3886.
Not to go against better judgement, but I doubt it's horrific. Active is probably better, but then again...I was pretty satisfied with my $30 Logitech 2.1 system which had absolutely no crossovers whatsoever...
The two satellites are being run off of 2x LM3886.
Not to go against better judgement, but I doubt it's horrific. Active is probably better, but then again...I was pretty satisfied with my $30 Logitech 2.1 system which had absolutely no crossovers whatsoever...
Most people really have no idea what "Low" bass really sounds like. In fact when it's really low, you tend to feel it more than simply just hear it. What most people really seems to like, especially with movies, is "punchy" bass.
If you want to achieve true audio nirvana and get theoretical low bass, you have to build it big, and I mean BIG. Remember that woofer in "Back To The Future?"
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