[kgb_m3]

Hey guys I'm new to this forum, been browsing around and seems like there's some good info and people on here.

With my new computer build and a recent sound card upgrade I've become somewhat addicted to proper sound. I listen to all kinds of music and do some online fps gaming. For a while I've been using Logitech 2.1 z-2300 and although they sound best out of any computer speakers that I've heard, I felt the need to upgrade. The new sound card is Auzentech X-Fi Forte 7.1 and I'll be getting a set of Polk Monitor 30 bookshelf speakers in mail tomorrow.

My goal is to have a 2.1 type system which would consist of keeping the Logitech z-2300 sub while getting the best possible sound out of the Polk 30s that will substitute the Logitech satellites. For those not familiar z-2300 has a built in amp and puts out 40w rms to L and R channel in a form of RCA jack. I did solder some speaker wire to a spare set of RCA jacks to see how the Polks will sound being powered straight by the Logitech amp once they arrive tomorrow.

I'm thinking ahead and trying to get the best out of Polks, have a feeling the Logitech amp won't be sufficient enough for the job. What are my options guys? I'm in electronics so I can put together a couple of hundred watt stereo audio amp to power the Polks, but how would the Logitech sub still run? I will also later would like to replace the 8" driver by the RE one from amazon. If building one isn't going to be worth the hassle, is there an inexpensive stereo amp your guys can recommend? Any advice would be great!

 

[Menisk]

Bottom of the range NAD is great for it's price and would be more than enough for running two bookshelf speakers, dunno how you'd do the amp though.

 

[Operandi]

If you can handle electronics you should send the Polk's back and build your own speakers and sub w/ this class D 2.1 plate amp from Dayton Audio. There are lots of designs to choose from, all of which would smoke the entry level Polks.

 

[kgb_m3]

Thinking about building this amp
PA100 DIY 2x LM3886 in parallel gainclone audio amplifier

I really don't have time to build speakers now, I will eventually, the polks were super cheap and can always be used for garage speakers or whatever. If I build the amp for now, I can always build a nice set of speakers later and use them with the amp.

 

[jawor121]

I couldn't find this information; do you know how much would all the parts cost to build the amplifier above?

 

[Operandi]

Quote:

Originally Posted by kgb_m3 /img/forum/go_quote.gif Thinking about building this amp PA100 DIY 2x LM3886 in parallel gainclone audio amplifier I really don't have time to build speakers now, I will eventually, the polks were super cheap and can always be used for garage speakers or whatever. If I build the amp for now, I can always build a nice set of speakers later and use them with the amp.

Hah, well pairing that amp with those speakers would be kinda like dropping in the V8 from the BMW M3 into an 80's Kia. I guess you would be set for the amp though, and that dose look like a nice project and def. a killer amp.

About the speakers, Parts Express sells some really nice prefabbed cabinets that would knock 90% off the time needed to build. The 0.25 or 0.375 cabinets would be just about the perfect size.
.25 CABINET from Parts Express ship same day and come with 45 day money back guarantee. Free Shipping Available. Order free 10,000 product catalog.

 

[kgb_m3]

Haha I know about the amp being overkill, but it's better to build a good one once that would also work for other speakers in the future. The Polks even running off the Logitech amp sound incredible, night and day difference from the stock satellites.

What I'll do is build the custom amp, meanwhile use the Polks with the Logitech amp. After the amp is built, I'll start on some nice custom speaker build to complement, Polks I'll use in another room to replace some old Onkyo junk.

Thanks for the advice and the link above, I'll be sure to post the progress on the amp build. Parts shouldn't be too bad, $150+ and I should have some laying around in the garage.

 

[LUCIDD]

I'd love to see your custom amp...

and would love to know more about building of amps - but alas, it is definitely not my forte - complex electronics.

I did do something very simliar with my computer speakers: altec lansing ACS43 --- not as powerful as your Z2300's but it does have sub-out connection.
I connected a series/parallel set of midrange drivers, built 1 custom enclosure, and left the some of the drivers in its original enclosure - running 2 tweeters [1 aluminum, 1 silk dome] 4 midwoofers [yamaha] per channel -keeping impedance at between 3-4ohms. Then added another cheapy taiwanese 2.0 amp, drivers and tweeters for fill.
I have the sub-out connected to my HT klipsch sub10 which fills in the sound below 90hz. Sounds ok-good- loud, but of course sound stage is lacking... Not as good as my computer monitors.
This was my first project. I then built 1 custom enclosure housing 12x 1.5" Altec Lansing aluminum full range drivers with neodynium magnets. The enclosure acts as a laptop pad... I also had to put in a 4" Cambridge soundworks woofer to get a little more bottom end. The system and it's sound was very dependant on the type of amps I connected them to. Most of the time, issue was the crossover point "-SUB- to SATELLITES" I needed something that had a lower crossover - 100hz or so. But most amps crossover at 140-150hz which is too high - sending too little [only the mids and highs] to my full range drivers....

Sorry for the rambling... but the point I'm trying to make is: if you think your Polks sound good now, wait till you get the amp to send more low freqencies to your Polks! [I would have done this to my amp if I know how to - instead, I just looked on craigslist for the right types of computer speakers with the right crossover-lol

]... but since you know how to work with this stuff - you can lower the crossover to [your polks go as low as 63HZ +-3db]... say 70hz and I'm sure your sound will improve drastically.
Your current crossover point of your Logitecs are probably set at 110-150hz[guessing]... so by the change, you'll gain 47-87hz of response potential from your Polks!

Also, another easy optimizing improvement to your current setup is: since your Polks are running 8ohms -whereas your Logitec amplifier is at 4ohms... If you match the amplifier 4ohms - you will run higher efficiency and/or accuracy. Perhaps wiring the Polks with your original Logitech Z2300 satellites [4ohms] in series will lower your impedance to 6ohms - or wiring another set of 8ohm speakers to your Polks [if you have any] and yeild an optimal 4ohms.

Let me know how it goes!

______________L

 

[kgb_m3]

LUCIDD, great post man!! I would like to see pics of your above mentioned builds, of course if you don't mind. Also a few other things, first I want to figure out if this setup will work

My sound card has the following analog I/Os and is setup as follows:

Microphone Input - mic connected
Line Input - n/a
Front Output - Logitech z-2300
Rear Output - n/a
Center/SW - n/a
Output Side Output - n/a

Now I definitely feel the need for a custom amp, Polks although sound much better than satellites need to be powered by a proper amp with proper Hz range. Just like you mentioned, I would gain more range with those Polks bypassing the crappy crossover point in the Logitech amp. Going back to the above table, I have 2.1 selected in the audio control panel. Is it possible to have my custom amp connected to the Front Output, while the Logitech sub (powering no speakers now, just itself) connected to the SW output and have it theoretically work in 2.1 or would 5.1 need to be enabled within the sound card setting? So it would be like this:

Microphone Input - mic connected
Line Input - n/a
Front Output - My custom amp powering Polks
Rear Output - n/a
Center/SW - Logitech z-2300 no speakers attached
Output Side Output - n/a

If the above works I could have the Polks properly powered, proper response range and still retain my Logitech sub.

-------------------
Btw the Logitech amp is 8ohm not 4, so running 4ohm speakers will most likely destroy it. I'm also experiencing right channel drop out here and there, rca connectors might be loose on the inside. (wont be a problem once the custom amp runs the Polks)

 

[Operandi]

kgb_m3 Assuming your sound card drivers let you set the crossover point you could really incorporate the Logitech sub is if you rely on software volume controls at the OS or app. level.

Are you sure it's only $150~ to build that amp? I always thought Gainclones were a bit more expensive $300+? Have you checked out 41hz Audio?, they have some really nice kit amps too.

Quote:

Originally Posted by LUCIDD I did do something very simliar with my computer speakers: altec lansing ACS43 --- not as powerful as your Z2300's but it does have sub-out connection. I connected a series/parallel set of midrange drivers, built 1 custom enclosure, and left the some of the drivers in its original enclosure - running 2 tweeters [1 aluminum, 1 silk dome] 4 midwoofers [yamaha] per channel -keeping impedance at between 3-4ohms. Then added another cheapy taiwanese 2.0 amp, drivers and tweeters for fill.

You can't just randomly throw speakers together in a box and expect good results, thats just recipe for disaster. There are plenty of good full range drivers out there that would be good candidates for experimentation. If you are going for something more though you NEED a properly deigned crossover, even if its just a minimalistic one.

 

[kgb_m3]

I'm not sure how the software will work being setup that way. Auzentech Forte X-Fi comes with the same control panel as what comes with a Creative X-Fi (whatever the highest gaming card is) If that sounds familiar I may be overlooking something. The only thing I've found is a bass gain option with crossover, but that seems like it allows you to choose the crossover point up to which to boost bass, options are from 10 - 250 hz.

So you're saying that I can in fact run my amp out of the front output to power the Polks and have the Logitech sub plugged into the SW port, while leaving the setting in the software control panel as 2.1 or would it have to be 5.1 or not work that way at all? It would make it much easier for me to go on once I know this. Hopefully the software is designed to work a proper way.

Also today I was planning on ripping apart the Logitech sub and seeing what type of amp they used and if there's a way to upgrade it. I can't believe there's no pic, info, anything of it online. There's a possibility that I can modify the amp to where I can chose my own crossover point to the Sub, beef up the output to up the gain a little more, etc... Could run in to PSU problems at that point or not enough voltage supplied to the amp from whatever PSU Logitech used.

I'm still building the amp regardless of what route I take, but my ideal setup for now would be my own amp running the Polks and the Logitech sub plugged into the SW output of the sound card with a proper crossover setting. As far as pricing goes, I've added up most parts, it's closer to $200 without any connectors, enclosure, wire, etc.. Just electronic components, not even counting the heatsink. So I'm looking close to $250 or so without cutting corners.

I'll know more once it's apart, (roommate is sick, passed out on the mattress on the floor blocking all access to the sub) complete fail

Checking out 41hz site, thanks for the link. Will post some pics of progress soon!

 

[Operandi]

I'm not sure how that sound card works, I'm sure someone else dose though...

You could just use a splitter cable and use Logitech's crossover. It will still work but there would be a lot of overlap since PC speakers are crossed so higher (much closer to 200 than 100hz).

Honestly I don't really think it's worth it, its not like it's a great sub to begin with. Why don't you get the 2.1 plate amp I linked to above and use that instead of building that Gainclone? Logitech uses Tang Band drivers that are well known so you could even salvage the driver from the Logitech sub and build a proper box for it. Something that isn't made of particle board, dosn't resonate like crazy, and tuned to decently low frequency.

 

[LUCIDD]

Kgb_M3,
Don't mind at all

Here's a few pixs of my portable system- the one with 12 x1.5"drivers +1 woofer. The grill may have Yamaha on it... but rest assured - just the grill is made by Yamaha - I'll take the logo off later lol.

It is designed for placing a laptop on top - to watch movies etc... it is designed for close field listening for laptop use.

As far as your setup... I'll leave it for next post. Christmas duties... BTW, Merry Christmas everyone!!!

__________L

 

[LUCIDD]

So whether your posted setup will work??

Microphone Input - mic connected<BR>Line Input - n/a
Front Output - My custom amp powering Polks
Rear Output - n/a
Center/SW - Logitech z-2300 sub no sat-speakers attached
Output Side Output - n/a

It should work - definitely. .. but one concern - is how would the X-fi's crossover setting affect the z-2300's amp crossover setting. Then in your case, you'd be running 2 totally separate amps --hmm...

But will it work?? YES.

My suggestion is to

~~build your custom amp for the Polks... power them 10hz lower than they can handle [and all the way up to 24khz of course]... and forget&nbsp;about the sub for now. If the ratings on the polks are correct and true - they can reach 63hz... for computer/closefield/small room - they will more than suffice!<

~~Sell the Logitech Z2300 [craigslist: dunno what you gonna get but the resale on these are good as they are still being sold at bigbox stores]. Get some $$ and put towards next thing:

~~Then research for good powered sub/good bang for buck-- Velodyne, Polk, Audioengine, etc whichever brand -I'm sure you'll do your forum research

This way, you will be running a real subwoofer - instead of a computer sub [I think that Z2300 sub is decent - and sounds decent -not audiophile quality - but works well] that has the unecessary stuff for the satellites -&nbsp;with locked crossover...;which can possibly affect harmonics??? Not sure - you can try.

Hmm... comes to think of it, your software crossover will only work untill it hits your Z2300 crossover point. You probably won't go that high - but let's say you want to... then you'll lose frequencies because the 2 crossovers are cancelling each other out.

the Z2300 is 8ohms?? - Wow almost all of the computer speakers I've worked with are rated at 4ohms. I stand corrected.

Good luck!
_________________L

 

[LUCIDD]

Quote:

Originally Posted by Operandi /img/forum/go_quote.gif kgb_m3 Assuming your sound card drivers let you set the crossover point you could really incorporate the Logitech sub is if you rely on software volume controls at the OS or app. level. You can't just randomly throw speakers together in a box and expect good results, thats just recipe for disaster. There are plenty of good full range drivers out there that would be good candidates for experimentation. If you are going for something more though you NEED a properly deigned crossover, even if its just a minimalistic one.

Operandi,

The 2 projects were really for fun- and for learning experience only. They do sound good [imho] - especially the 2.1 multidriver setup. It is connected to my coffee table - and you can only see 2 of the driver enclosures- which are elevated above the top with metal brackets- relieving space for usage. Disaster? - well... the only thing close to a disaster - is that I burnt 2 small computer amps [cyber acoustics 2.1/2.0]because of major impedance missmatching making the laptop speakers.

Other thing is cost: - drivers for the laptop speakers were from Altec Lansing "XM2Go" docks - which I got for $2.71 each dock [2drivers each]---- It was from a liquidator. The amps were from old speakers collecting dust [cyber acoustics] + some comp.speakers that I got off craigslist for $15. All currency is CAD -LOL... inexpensive fun to say the least.

The 2.1 unit sounds good! - the only issue is that it clips when volume is at max [very loud btw]. Anyways... it was just a fun hobby-type learning experience. Definitely learned lots. -Gotta start somewhere right? Next project would be focussed on "audiophile" FLAT response... perhaps some unity horns

... Just fyi ... my main system is actually not DYI - so i got some reference to what sounds decent:
Pioneer 7.1 reciever, 6 Klipsch reference satellites, 1 Klipsch reference center channel, 1 Klipsch 10" subwoofer... running from my Quadcore HP slimline media center PC [with bluray/hd-dvd drive]... hdmi to Sharp Aquos Lcd... +Sony Ps3 for games.

Computer audio:
AudioEngine A2 : 2.0 monitor speakers. awesome/inexpensive little speakers that provide good sound imaging -especially when playing Flac files.

______________L