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Discussion Starter · #1 ·
I finished up on an experiment on my system today day to hear if I could get better sound by biamping (of a sort). I just bought the Granite Audio 770FP preamp I reviewed for Positive-Feedback a few months back, and it is designed so that the two sets of outs are physically isolated from each other, not bridged, so the amps will not interact with each other.


I have a Parasound 5 channel amp, and I wondered how much better the music would sound if I used 4 channels instead of 2. So technically speaking this is not really biamping, but a close second. For this test, I replaced my Tara Labs biwire run with 4 runs of cheap zip cord; the lows to one set of channels and the highs to another set.


Even with the cheapest of speaker wire, this experiment put my system on another level. My soundstage not only got a bit wider, but much, much deeper and more forward. Imaging became denser and the air around instruments increased. I am also hearing much more of a fullness or a richness to music that make it that much more enjoyable. On my PS Audio 600, I noticed that the wattage used went up to 300 from 270 just for normal listening.


The initial results of this experiment were so promising that I am going to replace my single run of Tara Labs biwire cable with two runs of Granite Audio 573 (8awg).


I have to say I am very pleased and a little amazed at these results, I had no idea that biamping could have such an effect; even with the cheapest of speaker wire and channels that are part of the same amp.


I'll let you guys know what happens after I break in the Granite Audio speaker cable.
 

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I have passive bi-amped before too, but the results were more subtle to my ears back then.


I have often read that those cheap flat metal jumpers that join a speakers bi-wire binding posts can be really detrimental to the sound. And that by just replacing those metal strips with a quality jumper can make noticable improvements too.


As a further experiment, rather than bi-amping them, try just bi-wiring them.


- Andy
 

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Discussion Starter · #3 ·
Hey Andy,


Actually I was bi-wired previously, and the improvement to my system dynamics after trying passive bi-amping was what all the fuss was about.


I was surprised that I got such a bump in dynamics, especially since I was using the cheapest zip cord I could find. I really can't emphasize enough how much more flavorful music is now on my system after passive biamping.


Have you used biamped previously with active crossovers?
 

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My current speakers ( I have had them for 3 years now ) are the Waveform Mach 17. They are an active tri-amped design and include a custom Bryston 3-way active crossover set at 325 & 1850 Hz with -24db/oct slopes. The crossover also has tone controls which makes it handy to tune the sound to my liking.

Here is a bit of info on them:
http://www.soundstagelive.com/factorytours/waveform/


- Andy
 

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Hi Mike,


I have used active crossovers and the benefits are much more pronounced than with passive bi-amping. The obvious question to ask, of course, is; are you sure you want to bi-amp or do you want to go to the next higher level amplifier? You must weigh the cost difference carefully. Is it worth the extra bucks to you?


I am a firm believer in active bi-amping and I feel that ANY amp can be improved by placing two of them in it's place. I still have my "OLD" (over 20 years now) Nakamichi EC-100 with its separate power supply. I still use it from time to time when experimenting.
 

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Discussion Starter · #6 ·
Dan,


Did you build your own active crossover or did you buy it?


Did you put your crossover between the amp and preamp or between the amp and speakers?


If you put the crossover between the amp and speakers, did you remove the crossovers in the speaker?


If you put your crossover between your amp and preamp, did you remove your speakers crossovers?


Anything else you might want to tell someone before they begin this journey?


Thanks.


Mike
 

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Discussion Starter · #7 ·
Andy,


What are you driving your speakers with? Would you mind listing your system?


Thanks.
 

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Quote:
Originally posted by Mike Malter
Dan,


Did you build your own active crossover or did you buy it?Mike
Both, but the Nakamichi EC-100 I mentioned is an active crossover. About $600.00 way back when. Probably worth about sixty dollars today. :rolleyes: It has its own power supply (PS-100) in a separate enclosure.

Quote:
Did you put your crossover between the amp and preamp or between the amp and speakers?Mike [/b]
Your active crossover should go between the Pre-amp and Amps. Your system becomes a "true" 2 way, or 3 or 4 etc., system using this method. Basically, one amp per driver if you will. :D At least one channel per driver. By placing the active here you set the frequency entering the amplifiers and therfore the 'unwanted' frequencies never even reach the speaker cable.

Quote:
If you put the crossover between the amp and speakers, did you remove the crossovers in the speaker?Mike [/b]
Placing the active here does little. In effect you have made an exterior speaker crossover that needs power. The crossovers almost always aren't compatible so typically, I remove the crossovers in the speakers when using an active crossover. At least bypass them. With speakers that already have bi-amp connections it might not be necessary to remove or bypass the speaker's crossover as long as you can set your active to the same frequency. As was mentioned above by Andy, some speakers already have their own active crossovers with separate connections ready for bi-/tri-amping. This makes the separate active unnecessary. Check your speakers and any warranty that you may void if you crack them open. I am not telling you to void a warranty as an experiment.

Quote:
If you put your crossover between your amp and preamp, did you remove your speakers crossovers?Mike [/b]
Yes.

Quote:
Anything else you might want to tell someone before they begin this journey?Mike [/b]
Don't be afraid to move the crossover around. Try it in the different locations you asked about and see which location you prefer. I suspect you will settle on placing it between the preamp and amps. This is where you get the most benefit.

Quote:
Thanks.


Mike [/b]
I hope this helps. I'm sure it will be a learning experience for you and it has some nice rewards. I have an old Technical reprint from Crown Sonics that's from their winter 76/77 issue. It may be old but it gives the information in laymens terms and it all holds true today. Give me your email addy in pm and I'll send it to you. I would scan and post it here but I havn't played with posting images in this forum yet.
 

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My system details are here:
http://cgi.audioasylum.com/scripts/mail.pl?user_ID=367


My Waveform speakers are designed from the ground up around an active crossover.


I don't "buy" into ripping out your speakers passive crossover and inserting an active one. Your speakers sound is based around its drivers, cabinet, and passive crossover implementation. This includes the choice of crossover slopes, and parts "quality" used to build the passive crossover. You just can't try and convert/mimic this passive implementation with an active replacement and expect your speakers to sound the same.


Same thing goes for active crossovers -> they don't all sound the same as each brand has its own power supplies, op-amps, resisistors, caps, inductors, etc, in its circuit design.


So I think taking a finnished speaker prodcut and trying to re-enginenr it is somewhat risky sonic business, but a ground-up DIY speaker is another story. Either way, playing is fun & educational, and you can always undo your experimentation.


- Andy
 

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Discussion Starter · #10 ·
Andy,


My thoughts exactally. I was not thinking about ripping out my passive crossovers. I am thinking of a DIY type of project that would involve active crossovers.


Something else I am thinking about are passive crossovers between my preamp and amp to only allow either a high or low band of frequency to pass.


Currently I am running a pair of Vandersteen subs, so I am already using a high pass filter.


I imaging using caps would somewhat degrade the sound a bit, but I wonder if the extra dynamics might be worth it.


Do you have any contacts for places where I might get some caps made? I did come across a DIY article, but the caps were inexpensive ones from Radio Shack, and I don't know enough about what better caps to use, and if the design is any good.


Thanks.
 

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Mike,


Don't misunderstand what I said earlier. I am in no way advocating that you should try to re-work your finnished speakers. Everything that Andy said is true, you will change the sound and not always for the better.


What I am saying is that if you bi-amp there are definate advantages. With todays speakers it often isn't necessary to use an external crossover because, as Andy points out, the finnished speakers that you spent so much money on and like so much, already have the best crossover for that speaker. Besides, most "quality" speakers are designed with bi-amping in mind. Leave those alone and run the amps 'open' (without an external crossover) into the proper connections using one amp per driver or driver group. If you want to limit the frequency being fed into the amps then you will want to use an active crossover.


In a DIY speaker don't hesitate for a second to take out the passive crossover.
 

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Discussion Starter · #12 ·
Dan,


Got it, I understood. Thanks for all of your info.


This active crossover thing has me really thinking.
 

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Quote:
Originally posted by Andy Lammer
I don't "buy" into ripping out your speakers passive crossover and inserting an active one. Your speakers sound is based around its drivers, cabinet, and passive crossover implementation.
I agree, but am curious on HOW my JBL S312 main speakers are crossed (@ 750, 3000Hz). ;)


I'm inspired to DIY my own sealed full range main speakers w/matching sealed sub (16Hz with 20-25/20,000+Hz +/- 1-3dB) using passive 1st order and 2rd-4th order for tweeters if needed.


I did a lot of research on active analog and digital components (Rane, dbx, DSS, Behringer, Marchand, Bryston...). Also DSP's, IIR, FIR filters in a HTPC, but decided on a "Bruce Lee/be the water" approach (avoid another signal path)... It would be interesting keeping all sampling with DSP's all in the digital domain - like before the analog outs in a sound card. Creamware sound card DSP's let you "play" with 4th order LW curves, phase/time delay... I heard though IIR and FIR filters are not perfect in themselves, but 24-bit digital volume/attenuation done right is virtually invisible.


Bi-amping (even tri-amping) is interesting. Very good ideas, even implementing a crossover in the amp... If I need to I may just get a bigger stereo amp for the mains. Run a matching stereo amp to the sub with dual voice coils for 2.1. For 5.1, get a mono sub amp and use the stereo amp for 2 channels in the surrounds…


Here's some good links I came up with:


This calculator - two-way first-order Butterworth crossover network http://www.carstereo.com/help/Articles.cfm?id=8

Loud Speakers 101 http://www.carstereo.com/help/Articles.cfm

Two-Way Crossover Network Design http://www.carstereo.com/help/Articles.cfm?id=3

Multi-Way Crossover Design http://www.trueaudio.com/st_xov_1.htm

Two-way cross-over basics. What IS a crossover? http://www.mmxpress.com/technical/twoway.htm

Balanced vs Unbalanced, Passive vs Active http://www.bssound.com.au/advice/bsadvice.htm

Building your own 2nd order passive Crossover network http://www.colomar.com/Shavano/crossover12db.html

The Subwoofer DIY Page v1.1 Subwoofer Integration http://www.diysubwoofers.org/misc/sub_integration.htm

RME level adjustment +4/-10 dBu and servo balanced inputs and outputs http://www.rme-audio.com/english/aeb/index.htm

Matt's DIY audio page http://kahuna.sdsu.edu/~tucker/diyaudio/diyaudio.html

X-overs and Bi-amping http://kahuna.sdsu.edu/%7Etucker/diy...ramblings.html

24db/octave Linkwitz-Riley http://kahuna.sdsu.edu/%7Etucker/diyaudio/xover.html

Active Crossovers for DIY Speaker Builders http://www.snippets.org/filters/crossover.htm

THIEL SmartSub Controller - "Do I need a crossover?" http://www.thielaudio.com/THIEL_Web/...needxover.html

The HS500. The most powerful plate subwoofer amp available to the DIYer today http://www.adireaudio.com/diy_audio/...iers/hs500.htm

Integrating A Subwoofer With Your HiFi http://www.audioetc.tv/articles/inte...erwithhifi.htm

Subwoofers for Music - EXCELLENT http://www.soundstage.com/maxdb/maxdb200101.htm

Google search - subwoofer low frequency cut-off filters (e.g. 16Hz…) http://www.google.com/search?hl=en&i...ut-off+filters

Why is it so difficult for subwoofers to blend into a system? http://www.vandersteen.com/pages/Answr9.htm

The Marriage Between the Subwoofer and Tower Speakers http://www.***********.com/techtips/...fer_towers.php

ACI Subwoofer Primer http://www.audioc.com/information/subwoo.htm

It is common knowledge that crossovers contribute to coloration http://www.merlinmusic.com/reviews/hfr_495.htm

SPEAKER PASSIVE CROSSOVER ASCENSION http://www.jensencapacitors.com/audi...s/artikel.html

"crossoverless" speakers http://www.onhifi.com/askwes/ask0014.htm

Removal of the crossover eliminates phase & group delay distortion http://www.brentworth.com/

and delivers a musical performance that has every nuance preserved

Why horns http://www.hornspeakers.info/

Adire Audio - Maelstrom http://www.adireaudio.com/diy_audio/.../maelstrom.htm

Neutralizing L(e) with a Zobel Network http://www.trueaudio.com/st_zobel.htm

Subsonic Filters are high-pass crossovers centered around 25-30Hz http://www.rockfordfosgate.com/scrip...php?p_faqid=68

subwoofer subsonic filters - Google search http://www.google.com/search?hl=en&i...bsonic+filters

SVS Amp Interface by Marchand Electronics http://www.svsubwoofers.com/marchandsubsonic.htm

No need for subsonic filtering - sealed design http://www.danmarx.org/audioinnovation/theories.html

Sealed Subwoofers http://www.acc.umu.se/~sagge/audio/1259/

Sealed Speaker Enclosure Design Calculator http://www.loudspeakers101.com/SealQtc.htm

How The Linkwitz Transform Circuit Works - and qtc .707 sealed subwoofer http://sound.westhost.com/linkwitz-transform.htm

Therefore a hipass or "subsonic" filter, even for sealed boxes, could help reduce distortion http://www.diysubwoofers.org/projects/cartf/

Sealed Box Subwoofer http://home.insightbb.com/~stephenwm..._Subwoofer.htm

Marchand WM8 "BASSIS" Bass Correction Equalizer http://www.marchandelec.com/wm8.htm

The sealed system provides the best group delay numbers http://www.adireaudio.com/tech_papers/sub_gd.htm

Phase, Time and Distortion in Loudspeakers http://sound.westhost.com/ptd.htm

speaker sub enclosures http://www.madisound.com/

REL Strata III Subwoofer review - let mains run full! http://www.21stcenturyservices.com/audio/REL_Strat3.htm

The Perfect Subwoofer http://www.21stcenturyservices.com/audio/perf_sub.htm

Extended Low Frequency or ELF - mains run full… (active sub) http://sound.westhost.com/project48.htm

Thiele - Small Analysis of Loudspeaker Enclosures http://www.silcom.com/~aludwig/Sysde...l_analysis.htm

250W SUBWOOFER AMPLIFIER w/REMOTE CONTROL http://www.partsexpress.com/pe/pshow...=300-793&DID=7

subwoofer Class D - Class AB amplifier http://www.xcs.no/index.php?artikkelid=67&back=1

KGND-52100 Powered Subwoofer Amplifier Class D 1000 Watts @ 4 Ohms http://www.madisound.com/kgnd.html

Velodyne SPL-800 Class D subwoofer amp review http://www.***********.com/productre...SPL800-p3.html

subwoofer in and out of phase, phase reversing - Google search http://www.google.com/search?hl=en&i...=Google+Search

Audioreview - subwoofers http://www.audioreview.com/Subwoofers/PLS_2741crx.aspx

Welcome to Madisound Speaker Components! http://www.madisound.com/

The Subwoofer DIY Page v1.1 Definitions http://www.diysubwoofers.org/misc/dumax/dumax.htm

Updated NOUSAINE subwoofer data list http://www.avsforum.com/avs-vb/showt...light=nousaine

Updated NOUSAINE subwoofer data list http://members.cox.net/frankcarter/T...Sub%20Data.htm

True Balanced outputs http://www.avsforum.com/avs-vb/showt...hreadid=301971

subwoofer calibration system - software http://www.etfacoustic.com/

Adire Maelstrom Speakers Review by Pland http://www.audioasylum.com/audio/spe...ges/97841.html

THE ANCIENT AUDIOPHILE'S QUEST FOR THE ULTIMATE HOME SYSTEM http://invalid.ed.unit.no/~dunker/ultimate.html

ð Speakers Frequency Response http://www.pispeakers.com/PiGraph.htm

Multiple Subs http://www.avsforum.com/avs-vb/showt...hreadid=298137


Biamplification basics - an article http://www.audioasylum.com/audio/gen...ges/57210.html

DIY speaker building information http://home.earthlink.net/~etunstal/diy.htm

DIY Loudspeaker Designer's Selection Guide (the LDSG) http://ldsg.snippets.org/index.php3

A summary of recommended speaker design software packages http://ldsg.snippets.org/appdx-c.php3

Section 7 - Recommended drivers http://ldsg.snippets.org/sect-7.php3

Recommended drivers technical specifications http://ldsg.snippets.org/sect-12.php3

Appendix A - Loudspeaker Design http://ldsg.snippets.org/appdx-a.php3

LDSG Appendix A - Enclosure designs http://ldsg.snippets.org/boxes.php3#SEALED

Section 17 - Suppliers of prefabricated enclosures http://ldsg.snippets.org/sect-17.php3

Section 16 - Recommended louspeaker kits and plans http://ldsg.snippets.org/sect-16.php3

Speakerbuilding.com http://www.speakerbuilding.com/content/1014/page_5.php

Home Audio DIY Speaker FAQ http://www.lalena.com/audio/faq/speaker/

Details of the VR-6 and VR-8 Technology http://www.vonschweikert.com/vrline/VR-6W.HTM

JPO Speakerbuilding Linklist http://members.chello.se/jpo/

Try downloading a program like WinISD Pro alpha http://www.linearteam.dk/

Welcome To DIYSPEAKERS.NET http://www.diyspeakers.net/

spherical cermaic speakers - least distortion http://www.zako.com/techrev.htm

How to Design a Sealed Loudspeaker? - Qts, Fs sealed speaker enclosure… http://gecko.gc.maricopa.edu/~jmurba...dio/sealed.htm

Thiele-Small Terms and Definitions or just "T/S Parameters" http://www.mmxpress.com/technical/terms.htm

Zobel Networks, speaker design http://www.adireaudio.com/tech_papers/tech_central.htm

Speaker design calculator http://www.mhsoft.nl/spk_calc.asp

Neutralizing L(e) with a Zobel http://www.trueaudio.com/st_zobel.htm

Initial Enclosure and Crossover Designs - Zobel network http://www.angelfire.com/electronic/...modelling.html

Passive Crossover Basics - Zobel Networks http://www.eatel.net/~amptech/elecdisc/xoorder.htm

Crossover Design http://www.silcom.com/~aludwig/Sysde...ove_Design.htm

Sample 3 Way Crossover http://www.lalena.com/audio/faq/xover/

DIY audio homepage http://www.lalena.com/audio/

The Loudspeaker Design Cookbook - $39.95 http://www.amazon.com/exec/obidos/tg...91827?v=glance

Part II: Digital Filters* http://www.silcom.com/~aludwig/Signa...al_filters.htm

Design of the Sound System http://www.silcom.com/~aludwig/Sysde...und_system.htm

Crossover Design http://www.silcom.com/~aludwig/Sysde...ove_Design.htm

Construction of the Loudspeakers http://www.silcom.com/~aludwig/Louds...Time_alignment

DIY'ers perspective on the top-selling Bose system http://www.intellexual.net/bose.html

Design of Loudspeakers http://www.linkwitzlab.com/design_of_loudspeakers.htm

Crossovers - 1st order http://www.linkwitzlab.com/crossovers.htm

F - Group delay and transient response http://www.linkwitzlab.com/frontiers.htm#H

JBL horns, speakers http://www.usspeaker.com/

Impedance Equalization Designer Help - Zobel Networks http://www.lalena.com/audio/calculat...ual/help.shtml


3-way 1st order crossover is used in a 3-way vented enclosure system http://www.kbapps.com/audio/speakerd...xover3way.html

Slop Of The Crossover - tweeter/1st order @ 2kHz NO GOOD… http://www.caraudiogalaxy.com/caraud...pcrossover.htm

ScanSpeak tweeters - Google search http://www.google.com/search?hl=en&i...Speak+tweeters

tweeter 1st order crossover - Google search http://www.google.com/search?hl=en&i...rder+crossover

Time aligned, Phase coherent, Phase aligned, http://www.geocities.com/kreskovs/TimeAligned2.html

Transient accurate, What's up with that.
 

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Discussion Starter · #15 ·
Ray,


SOME links? This is a lifetime's worth of research and reading:) .


Thanks so much.


Hmmm.... digital crossovers? So you would be trying to shape the signal as much as possible before sending it to the speakers?


I just got another link that has some very interesting informaion about active crossovers. It is a manual for one of JBL's active crossovers, and it addresses the protection of drivers that are connected directly to an amplifier.

http://www.jblproservice.com/pdf/Vin...5%20manual.pdf


Thanks, I am going to start diving into your links. Great stuff!
 

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Quote:
Originally posted by Mike Malter
Ray,


SOME links? This is a lifetime's worth of research and reading:) .


Thanks so much.


Thanks, I am going to start diving into your links. Great stuff!
Yeah, definitely more than just a "few" links, he provided there. And that had to take him at least a minute or so to assemble....;)

As there is many good ones that I never even seen or knew about before. That was of interest to me as well.


So I thank him as well, for making that list available!
 
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