[TNRabbit]

(FYI: this is a cut & paste from a thread I did on another forum over the past couple of years)

Part 1

I pulled out the solder iron & bypassed the passive crossovers in my AL-IIIs today; it took about 2 hours all told to get the Ashley crossover installed (what a snakes nest behind the unit now with 5.1 setup!!) and unsolder the x-over and solder the speakers back inline with the fuses*.

(*Used a lower rated fuse now without the crossovers installed--2.5 amp -vs- 4 amp slo-blo)

Pic of the Ashly XR-1001 crossover:



About 15 seconds after I finished & was connecting the last speaker to the amp, a major storm blew through and knocked out our power for about 2 hours!! ](*,) ](*,)

The power came back on about the time & had decided to just go to bed, so I ran upstairs & got everything prepped, turned it on, adjusted the crossover and discovered....

....
....
...
...
...
...

I HATED the sound coming out of the ribbons (nasal-ish sounding), and the bass was weak! #-o

SO, I did some playing around with the levels, gave a little bit of treble boost via the TG-IV, and it's now sounding MUCH better, although I realize I'm not going to be happy until I get the Rane parametric equalizers in place (20 minutes left on the auction as I type this!) & shape the sound a little. First impression is the upper midrange is boosted a LOT with this direct connection, but I can also tell a lot of power has been freed up from the amp. The AL-III x-overs are real power hogs~

So far, things are sound pretty damned good :-" :-" :-"

More to come......................

[TNRabbit]

Auction just ended on the Rane parametric equalizers; got two of 'em, consecutive serial numbers, in really good shape for $122.00~ WOO HOO!
 





The passive crossover has are two notch filters to counteract the cavity resonances where the ribbon resides, one is at 2006Hz and the other is at 5932 Hz, so I have to account for those.

As you can see, these are professional EQs & have balanced TRS & XLR in/outputs.  I don't need any adapters for balanced inputs; my Sunfire Theater Grand-IV and Cinema Grand Seven Signature both have them~
 
I also have to say the Ashley crossover is DEAD SILENT....even better than I was expecting!
 
HOLY SMOKE will this sucker get LOUD now!!!

[TNRabbit]

Pics of the passive crossover surgery:







Right now-just based on what I hear, I've got the woofers bumped up about +2.5 (not sure if that's dB or what, but that's on the Ashley's scale) and the ribbons -1.0 for level, then the crossover is set to 200 Hz with a 6 dB/octave slope (Linkwitz-Riley filter has a −6 dB gain at the cutoff frequency).
 


Sounds faster/tighter than before.

"with an active crossover, the power amplifiers are directly connected to the speaker drivers, thereby maximizing amplifier damping control of the speaker voice coil, reducing consequences of dynamic changes in driver electrical characteristics, all of which are likely to improve the transient response of the system"

(from Wikipedia)

[TNRabbit]

Active Bi-Amping FAQ for anyone wondering what the h@ll it is I'm doing:

“What is Active Bi-Amping?”

Active bi-amping uses one amplifier for low frequencies and another for mid/high frequencies—per audio channel. This is done via the use of an active crossover unit which is inserted between the preamplifier and power amplifiers.

“What are the advantages of active bi-amping?”

1) It provides much greater driver control than a passive crossover/full-range-loaded amplifier configurations.

2) It provides a better load for your amplifiers to drive, and an effective gain in each amplifier’s effective output. It will provide lower amplifier-originated intermodulation distortion (IMD).

3) It provides much greater protection of your tweeter/midrange drivers under clipping/overload conditions.

4) It provides the ability to use less expensive amplifier designs for each driver.

5) It provides for time alignment of drivers within a single speaker (a “must have” capability)

6) It provides for better crossover performance in both amplitude AND phase in the crossover region for smoother crossover performance, including more stable soundstage imaging vs. frequency.

7) It provides stability of crossover performance relative to passive crossover drift during and immediately after under high-load speaker output conditions, i.e., it maintains electrical output linearity under heavy load conditions.

It requires lower-quality wire/connectors than a similarly configured passive crossover/full-range amplifier configuration.

9) It allows on-the-fly changes in crossover frequency, EQ and channel gain settings to support changes in your setup configuration, i.e., facilitating the fine-tuning use of tools like Room EQ Wizard [REW], replacing individual drivers, speaker position changes, and adding channels for playback (2.0, 5.1, 7.1, etc.).

“What are the disadvantages of bi-amping?”

1) It requires two power amplifier channels per speaker (with associated wires/connectors).

2) It requires an active crossover unit.

“What is an ‘active crossover’?”

1) An active crossover provides separation of frequencies of the incoming pre-amplifier output signals, breaking each upstream channel into two downstream channels (a woofer channel and mid-range/tweeter channel).

2) It provides higher-quality equalization (“EQ”) capability for each channel.

3) Digital crossovers typically provide for delay to allow for time alignment of the drivers within a single speaker. (This is a similar function to an AV Processer that time aligns speaker-to-speaker in a 5.1/7.1 array.)

“Do I need to disconnect my speakers’ passive crossovers from my drivers?"

Yes. At least the woofer (or low frequency driver) must be disconnected from the passive crossover to permit bi-amping. If your speakers are 3-way (i.e., woofer, midrange, tweeter in each cabinet), then you may retain the passive crossover between the midrange and the tweeter if using bi-amping (…but for tri-amping, all drivers must be disconnected from the passive crossover networks)

Can I use ‘passive bi-amping’?”

Passive bi-amping does not bring the benefits of active bi-amping, only the disadvantages of extra cables and connectors. Generally, it may not worth the expense of the extra amplifier, depending on your speaker power requirements. In particular, passive bi-amping does not provide for delay adjustment or filter/EQ parameter flexibility.

What active crossover brands/units should I use?

Many manufacturers make active crossovers, including ElectroVoice, Yamaha, Ashley, Behringer, Rane, Pass Labs, Marchand, Bryston, DEQX, etc. Prices go from around $150(US) to many thousands of dollars. Price is generally commensurate with sonic performance…

Have I seen active crossovers used in configurations other than a active crossover box?

Probably--the "powered subwoofer" channel found on most AV Receivers/Processors is a limited example of a for-purpose active crossover channel (i.e., mono bass channel). Usual features include gain control (at the integrated subwoofer/power amplifer unit), user selectable crossover frequencies, and sometimes Geometric GEQ/PEQ (graphical and parametric equalizer) filters built into the AVR/AVP.

Delay adjustment for each speaker channel is usually included in the AVR processor functionality to correct for speaker distance room placement variances. Additionally, an "Audyssey"-like feature on some AVRs/AVPs features a built-in real-time analyzer (RTA) to help the user set up their speakers in a room environment.


Also: http://sound.westhost.com/biamp-vs-passive.htm

[TNRabbit]

Got the Rane PE-15 EQs into place with judicious appplications of MORE XLR balanced cables...what a mess of cabling behind my unit:



At first, the Ranes exhibited an INCREDIBLE amount of noise; I mean I was almost ready to take them out & forget this entire project, it was so bad.  After they had a chance to warm up & I worked the scratchiness out of the pots & bypass switches, things got a LOT better.  I'm going to have to pull them & liberally apply De-Oxit to everything....I think that will clear things up considerably.

I am REALLY liking the whole active route, a LOT.  I highly recommend it.

Special thanks to mbskeam (Mike) who is building me a custom pair of stainless steel cover plates to replace the original crossover plates on the back of my AL-IIIs.
As far as I'm concerned this is going ABOVE & BEYOND what anyone could realistically ask for.

So, here's what the entire mess looks like now; sorry about the crappy pictures:





I'm going to be looking for a way to pack this all away in a rack as it's getting a little TALL for the desk....that's my next project~

[TNRabbit]

A recent addition:



I ordered new binding posts & circuit breakers/fuse holders to go with the STAINLESS STEEL panels a friend is making to replace the old crossover covers:

From Parts Express:



The fuse holders are the knurled-knob type vice screwdriver-removable ones currently in place (although I ordered a new set of those as well, just in case).  However, I also bought a set of 3 amp circuit breakers to try out:


Push Button 3A Circuit Breaker
Philmore # B7003
Same as GC 35-2103

    * Maximum DC Voltage: 50 VDC
    * Maximum AC Voltage: 250 VAC
    * Mounting Hole: .500"
    * Push to Reset
    * .250" Quick Connect


The rear panels will have the original mounting hole configuration so I can utilize the original screw holes, but I'm going to use these type of blind nuts with same diameter bolts --- the MDF doesn't like repeated insertion/removal of screws




At some point in the future, I'm also planning to try this wave guide (recommended by Bob Carver) to tame the ribbon resonance:

[TNRabbit]

Rane history FYI for anyone following this thread:

The Rane Story

Rane Corporation History & Philosophy

Rane Corporation, founded and incorporated in 1981 in Washington State, is a privately held company. The owners all previously worked together in middle management positions at Phase Linear Corporation, a high-end consumer electronics company. With this background, they pooled over 40 years of combined audio experience to create Rane Corporation. Owners became separate department heads based upon their expertise. This organization created an unusually strong structure, since all department heads had a unique owner's perspective in making it succeed.

The company name was selected from an anagram created from the common letters of the first and last names of the original founders. This particular anagram was selected because it was short, easy-to-say and remember, and they liked the double-entendre possibilities implying wet-links to the Northwest.

The essential ingredients in Rane's successful philosophy are knowledge, integrity, pride and common sense. At Rane, people learn to treat people the way they would want to be treated, to design & build products the way they would want theirs designed & built, and that when something goes wrong, you react quickly and decisively to correct it. It is an old fashioned, common sense way to run a business, based on mutual trust and respect.

Rane started out with four products aimed at small bands, designed to make their live performances better. At the forefront was a unique 12-input, 6-output matrix mixer (MM 12) used to create six different monitor mixes for driving stage monitor speakers. The idea was to help performers hear themselves better. Up to that time, either the small group had no monitors at all, or they were all driven by the same mix. What Rane provided was new, compactly designed, affordable tools to help solve the many problems of on-stage monitoring. Complementing the matrix mixer was the industry's first 6-channel power amplifier (MA 6), and a companion 6-channel headphone amplifier for rehearsal (HC 6). The fourth initial product was a unique combo unit, consisting of a 1/3-octave graphic equalizer and a simple realtime analyzer (RE 27), aimed at giving the performing musician a handy, easy-to-use tool for improving their sound in all venues. In doing all this, Rane established a new price-point for performance, quality and reliability. Rane products were priced well below the top high-end equipment yet outperformed and outlasted them, but were still priced significantly above the low-end products -- thus creating a new middle ground.

A noteworthy testament to Rane's design significance and reliability reputation, is that in their first two years of production, Rane designed and shipped eight new products -- five of which are still in production today.

Rane Corporation today is an established innovator in providing problem-solving professional audio tools, affordably priced, with unequalled reliability.
Rane Corporate Milestones

1981: Incorporated in Washington State, USA
1982: 1st Constant-Q EQ & 1st EQ/RTA combo unit - the RE 27
1983: AES paper: 4th-order state-variable Linkwitz-Riley crossovers
1984: 1st Linkwitz-Riley crossovers: AC 22 & AC 23
1986: AES Journal publishes Rane's landmark Constant-Q Graphic EQ paper
1986: 1st Interpolating Constant-Q EQ
1987: Rane's 1st digital audio product: AD 13 Audio Delay
1988: Publish PI 14 Pseudoacoustic Infector data sheet
1989: 1st 8th-order L-R Crossover
1989: 1st MIDI-Programmable EQs
1989: Develop Accelerated-SlopeTM EQ
1990: Patent: Constant-Q Topology
1991: Patent: Accelerated-Slope EQ
1991: 1st THX Home Cinema EQ: THX 44
1993: 1st Dolby Time-LinkTM pro audio delay
1994: Home Cinema Products launched
1995: PAQRAT® Digital Audio Recording System
1995: 1st RW 232 software product: RPE 228 Equalizer
1995: Launch website & Pro Audio Reference
1996: Mojo Series introduced
1997: Rane 1st DSP digital audio product: RPM 26
1997: Rane 1st teleconferencing product: ECS
1998: Patent: teleconferencing product
1998: New standard in DJ performing mixer: TTM 54
1999: Rane 1st Ethernet product: Via 10
2000: Rane 1st CobraNet products: NM 84 & NM 48
2001: Twenty-Year anniversary
2001: First magnetic fader DJ performing mixer: TTM 56
2002: Drag Net 100% drag and drop DSP
2003: DEQ 60 Perfect-Q Graphic Equalizer
2004: Patents: Magnetic Fader and Acoustic Echo Canceller
2004: SeratoTM Scratch LIVE digital audio computer interface
2005: SeratoTM MP 4 digital audio file mixer
2005: Digital Amplifier: MA 4
2006: Scratch LIVE Mixer: TTM 57SL
2006: Twenty-five Year Anniversary

We may be reached via telephone during normal business hours (8:00 AM to 5:00 PM Pacific Standard Time) at 425-355-6000. You may fax us any time at 425-347-7757.

Our postal mailing address is: Rane Corporation, 10802 47th Avenue West, Mukilteo, WA, 98275, USA

If you prefer hard copies of literature in the mail, you may email or call us at 425-551-1833.

[TNRabbit]

New binding posts & fuse holders:







....and the circuit breakers:




And the first pics of the stainless panel blanks before cutting:



...final product!







With parts installed (please forgive the fingerprints!):








So went from this:



to this:

[TNRabbit]

The saga of getting from A to B:

First you start here; the original screw holes for the crossover panels:



Drilled new holes to match the 6/32 stainless steel tapered-head bolts (1 inch):




Sized & cut some thin foam seal (originally made for lining a truck tool box) to prevent air leaks/farting around the panel:




Began de-soldering the crossover wiring:




Converted to 12 gauge OFC from monoprice from the thin original wiring:



FYI: Heat sinks make a HUGE DIFFERENCE in heat transfer to meltable plastic parts~


^^^I ended up soldering banana plugs to use with the woofer inside the cabinet as it was too difficult to try to solder in there. The monoprice bananas worked out GREAT & fit right into the woofer connectors (3/4 " on center).


I had to drill out the holes in the binding posts to get the 12 gauge wire through them:





UGLY solder joints w/heat sinks in place:






A shot of the port tube inside:



I think one day I might try upgrading to a "proper" port tube like this:

[TNRabbit]

I REALLY beat them up with some Donald Fagen today (The Nightfly & Two Against Nature); no fuses or circuit breakers blown (astoundingly!) & they sound terrific~

Now to just get the other speaker done....

[TNRabbit]

Been working on the other speaker today...

Also,I pulled the Rane PEQs & Ashly crossover out & cleaned all the switched & pots thoroughly with DeOxit.

All the pics are at this link...I got tired of linking them all~

http://s251.photobucket.com/albums/gg286/TNRabbit/Audio/?start=all

I'll import a few--

The Rane guts:




New system configuration:





At first....NO SOUND!  A few minutes of troubleshooting (of course, AFTER everything was put back together--GRRRR!).....

I had a couple of cables going into the wrong slot~ fixed~

Sounding good!

I used the DeOxit spray. It's impossible to wipe out the switches & pots, but I sprayed them, worked the pot/switch for a few minutes, then followed up with the GOLD. I used Q-tips for the connectors, wiped them well, let it sit, then wiped them off & used the GOLD as a follow up/protectant on everything.

Sneak peek:

[TNRabbit]

More vids:





Pardon the 1812 Overture; the video camera WAAAAY overmodulated....


I found symmetrical leading aircraft wing edges available in balsa wood for SUPER cheap ($2 each) & ordered several in both 1/2" & 3/4" sizes to build my waveform guides to correct the notch resonance. \/ I'll shape to fit & paint them black to match the ribbons:


That's a project for later....

Before/After Review:  I guess I'd have to say the main difference is CLARITY. Cymbals are crystal-clear; the "edge" of instruments shows through--saxaphone, trumpet, etc. Stringed instruments& awesome voices sound so good on great recordings it could just make your cry. The closest I can call it is a "graininess" that was there before & now isn't. Before, if I played at moderately loud levels, it would sound better after about 30 minutes, but never as good as now. My guess is the caps & in-line passive crossover components were aged & in need of replacement. If I had all new passive crossovers, PERHAPS the difference between passive & active wouldn't be as great. Too late to tell for certain now~

On top of that, a lot more headroom is available from the amplifiers; I give a conservative estimate that roughly 40% of available power was wasted on the passive crossover components.

I can't think of a single thing that's suffered (other than simplicity) from the upgrade. I highly recommend it! Just don't skimp on active crossover components, & get the most for your dollar there.

[TNRabbit]

(months later)

I spent a few hours this week replacing the circuit breakers on my AL-IIIs with fuse holders (not convinced they were working properly as they NEVER blew) in order to ensure a future for my ribbons/woofers.....

I also replaced the wood screws holding the woofers in with nice stainless steel hex-head bolts & blind nuts to save the MDF from certain destruction (had to tighten them occasionally as they tended to loosen from the vibration)

Pics:





















Heat sinks are important when working with insulated wire & plastic connector parts~


Wanted to post these pics of how the AL-III "wing" attaches to the bottom of the speaker enclosure, FYI:






Actually I'm glad I took them apart because 1 of the surrounds with was coming loose around the outside edge of the Infinities. Apparently, they changed the outer surround mounts at some point in production & glued them down with double sided tape. So, I re-glued them with silicone caulk. I was getting some strange bass sounds...that may have been why.

Now that I'm fully active, I might reconsider using JL Audio woofers instead of the Infinity ones. For those who don't know, I had decided on the Infinity woofers as they were at least 4 dB more efficient than anything else I found, but it's immaterial since I'm able to dial in the crossover to match....

[SteveFord]

I thought that beavers were the busy ones, not those wascally wabbits!