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Questions About Bi Amping With Electronic Crossover

47.196.126.54
Posted on October 17, 2021 at 19:27:36
ka7niq
Audiophile

Posts: 3835
Location: Tampa, Florida
Joined: September 4, 2001
 I have a Rolls SX 45 2 way electronic crossover. It is adjustable from 50 to 2500 and has 12 db slopes.
My questions is, if it is a 12 db crossover, shouldn't you reverse the phase of one of the drivers in a 2 way speaker, so you don't get a 3db bump at the crossover frequency ?
Or, does this crossover automatically reverse the phase of one of the amplifiers ?
I have included a schematic in the link.

 

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RE: Questions About Bi Amping With Electronic Crossover, posted on October 18, 2021 at 01:18:18
Coner
Audiophile

Posts: 3703
Location: S.W. Washington state, USA
Joined: November 17, 2001
 Offhand, I'd think that no, you don't reverse polarity, it's not
the same as using passive crossovers.

 

RE: Questions About Bi Amping With Electronic Crossover, posted on October 18, 2021 at 08:02:50
Bill Fitzmaurice
Industry Professional

Posts: 5370
Location: New England
Joined: October 20, 2002
 The summed response of filters at the crossover frequency is determined by the filter Q, not the filter slope. There can be a major dip at the crossover frequency with 2nd order/2nd order passives, as the total phase shift at the crossover frequency is 180 degrees. That's usually addressed by reversing polarity on the high frequency element, but a better option is to use a 3rd order high pass, which eliminates the 180 degree phase shift, while giving better driver protection and lower THD. Actives tend to not have phase summation issues.

 

RE: Questions About Bi Amping With Electronic Crossover, posted on October 18, 2021 at 08:19:14
ka7niq
Audiophile

Posts: 3835
Location: Tampa, Florida
Joined: September 4, 2001
 The Electronic Crossover I am using right now is only 12 db per octave, but I also own a DBX Driverack PA 2, and I think it allows choices of slopes and crossover points. It is not hooked up right now.
The Rolls SX 45 crossover I am using makes no mention of reversing phase in the manual, and I am told it is a 12 db Butterworth. I was told that any Butterworth crossover requires phase reversal, so I wondered if the Rolls crossover reverses amplifier phase internally ?

 

RE: Questions About Bi Amping With Electronic Crossover, posted on October 18, 2021 at 09:27:13
Paul Joppa
Industry Professional

Posts: 7295
Location: Seattle, WA
Joined: April 23, 2001
 The crossover linked in the initial post appears to be a standard biquad filter, with no sign of phase reversal internally.

In practice, the phase reversal recommendation assumes that the drivers are flat throughout the crossover region, and that they have no time delay difference. This is rarely the case, so usually you would try both options and listen to (or measure) the frequency response.

 

What Is The Easiest Way To Measure It ?, posted on October 18, 2021 at 09:44:52
ka7niq
Audiophile

Posts: 3835
Location: Tampa, Florida
Joined: September 4, 2001
 I have an Apple IPhone, and I was told there are some spectrum analyzer Apps that will allow me to measure the effects of reversing the phase of the amplifiers ?
Can anyone suggest a good App for the Apple IPhone ?

 

RE: Questions About Bi Amping With Electronic Crossover, posted on October 18, 2021 at 11:12:46
Bill Fitzmaurice
Industry Professional

Posts: 5370
Location: New England
Joined: October 20, 2002
 Whoever told you that should be ignored in the future.

Active and passive crossovers are inherently different. For instance, actives don't use inductors, so what applies to the one doesn't necessarily apply to the other.

 

RE: What Is The Easiest Way To Measure It ?, posted on October 19, 2021 at 08:19:41
Hornlover
Manufacturer

Posts: 2529
Joined: March 8, 2002
 Just go to the app store and search for 'spectrum analyzer'.

 

RE: What Is The Easiest Way To Measure It ?, posted on October 19, 2021 at 08:33:43
ka7niq
Audiophile

Posts: 3835
Location: Tampa, Florida
Joined: September 4, 2001
 There are zillion of spectrum analyzer Apps for the Apple IPhone, just wondered what some of the better ones were.

 

RE: What Is The Easiest Way To Measure It ?, posted on October 19, 2021 at 10:43:13
Bill Fitzmaurice
Industry Professional

Posts: 5370
Location: New England
Joined: October 20, 2002
 Any analyzer not calibrated for a specific phone model won't work.

 

RE: What Is The Easiest Way To Measure It ?, posted on October 19, 2021 at 10:47:36
ka7niq
Audiophile

Posts: 3835
Location: Tampa, Florida
Joined: September 4, 2001
 One would like to think that if the app is specifically for an Apple IPhone, that it is calibrated to the internal microphone of the Apple IPhone ?

 

RE: What Is The Easiest Way To Measure It ?, posted on October 19, 2021 at 13:00:34
Bill Fitzmaurice
Industry Professional

Posts: 5370
Location: New England
Joined: October 20, 2002
 Which iPhone? Aren't they up to #12? I guarantee they don't all have the same mic or frequency response.

 

RE: What Is The Easiest Way To Measure It ?, posted on October 19, 2021 at 13:15:52
ka7niq
Audiophile

Posts: 3835
Location: Tampa, Florida
Joined: September 4, 2001
 Good Point Bill, and you are correct, as usual.
Yes, they are up to IPhone 12, but I have IPhone11, and this App is explicitly for IPhone11 and up. https://apps.apple.com/us/app/spectrum-analyzer-rta/id490078884

 

RE: Questions About Bi Amping With Electronic Crossover, posted on October 20, 2021 at 21:00:37
KanedaK
Audiophile

Posts: 2519
Location: Brussels
Joined: April 27, 2010
 Play a sine wave of the crossover frequency.
Reverse polarity, play that same sine wave again.
Polarity that sounds louder is the correct one!

 

RE: Questions About Bi Amping With Electronic Crossover, posted on October 21, 2021 at 01:59:29
morricab
Distributor or Rep

Posts: 9178
Location: switzerland
Joined: April 1, 2005
 I am using a nano-digi from mini-DSP and I found that with 2nd order L/R filter that inverted sounds better overall...even though the measurements don't show a deep null as per theory in the non-inverted configuration.

It is best to try, listen and if possible measure.

 

Too Much Choice?, posted on October 21, 2021 at 02:37:54
cawson@onetel.com
Audiophile

Posts: 2378
Joined: September 27, 2004
 Avantgarde XD speakers have an electronic crossover built into their bass enclosures. The XD software allows, not only adjustment of the XO frequency and the XO slope (24, 12 dB, etc), but also the type of XD too - Butterworth, Bessel or Linkwitz-Riley. Is this too much of a good thing?

 

RE: Too Much Choice?, posted on October 21, 2021 at 04:53:56
Bill Fitzmaurice
Industry Professional

Posts: 5370
Location: New England
Joined: October 20, 2002
 It may be too much if you don't understand the advantages and disadvantages to the various options. One would hope that if someone was going to spend more on speakers than most people do on their cars that they'd take the time to learn how they work.

 

I don't have a Sine Wave Generator, posted on October 21, 2021 at 07:01:16
ka7niq
Audiophile

Posts: 3835
Location: Tampa, Florida
Joined: September 4, 2001
 But that is a great idea!

 

Found An Iphone Spectrum Analyzer App!, posted on October 21, 2021 at 07:34:57
ka7niq
Audiophile

Posts: 3835
Location: Tampa, Florida
Joined: September 4, 2001
 I plan to use this App to look at the frequency response BOTH ways, as soon as I find my Cell Phone Tri Pod Holder. I will play a pink noise video, then measure at the exact same volume level, and hopefully the spectrum analyzer will show me what way is best ?

 

RE: I don't have a Sine Wave Generator, posted on October 21, 2021 at 08:05:35
Bill Fitzmaurice
Industry Professional

Posts: 5370
Location: New England
Joined: October 20, 2002
 You can download a sine wave generator as a standalone or as part of a program as a computer program or app, many are available as freeware. But where doing an RTA is concerned you want pink noise anyway, which you can also download.

 

RE: I don't have a Sine Wave Generator, posted on October 21, 2021 at 08:54:17
Alpha Al
Industry Professional

Posts: 2958
Location: N. Carolina
Joined: February 16, 2004
Contributor
  Since: December 3, 2015
 As Bill F stated, you don't want a sine wave for that, you need pink noise.

A reasonable facsimile can be obtained by tuning your FM tuner between stations.

 

RE: Found An Iphone Spectrum Analyzer App!, posted on October 22, 2021 at 05:53:03
morricab
Distributor or Rep

Posts: 9178
Location: switzerland
Joined: April 1, 2005
 I used to use a computer system but now I use a Behringer DQX 2496 that has a nice 61 spectrum analyzer that has different settings like fast to slow and hold and average. This gives enough resolution to see the major and even some minor trends in the FR. It also has an integrated pink noise generator that serves as a good source for measuring the response.

The computer program was more accurate and resolved but harder to setup and slower with feedback...I can let pink noise run make the changes with the laptop software for the nano-digi and watch the FR shift in real-time.

 

RE: Found An Iphone Spectrum Analyzer App!, posted on October 22, 2021 at 06:16:23
ka7niq
Audiophile

Posts: 3835
Location: Tampa, Florida
Joined: September 4, 2001
 Thanks!
I downloaded a program, and just waiting on a device to hold my IPhone in a tripod to use it. Hopefully it will have enough resolution to pick up the differences in the phase reversal >

 

RE: Too Much Choice?, posted on October 22, 2021 at 07:07:48
cawson@onetel.com
Audiophile

Posts: 2378
Joined: September 27, 2004
 Unfortunately (or is it fortunately) I'm not an audio electronics wiz-kid so I prefer to leave this sort of job to someone who is - or just use Default settings that seem to do the job of presenting music in an amazingly realistic way.

 

RE: Too Much Choice?, posted on October 23, 2021 at 07:34:52
mnawaz3@aol.com
Audiophile

Posts: 502
Joined: March 28, 2002
 hi
my mood follows yours. but realistically, anybody who starts a non-turnkey horn solution, is asking to become a speaker desginer. at a minimum, the basic principles need to be understood. otherwise the speaker will likely sound like most DIY horn efforts-- good in a few areas --- terrible in others. in my experience, there are precious few good horn systems. fortunately, the few that are good are great. and listening to them makes you realize that you need to put in the effort or find alternate solutions(eg half-horn system like jbl 4367 or line arrays). for me, i would like my horn system to have coherence close to that of a speaker like dunlavy/duntech, harbeth m40, quad57.
unfortunately, that may take years (or lifetimes if under-equipped).

 

RE: Too Much Choice?, posted on October 23, 2021 at 09:22:52
claudej1@aol.com
Audiophile

Posts: 817
Location: Detroit
Joined: August 17, 2007
 Let me suggest Danley Sound labs. They have plenty of "turnkey" solutions to satisfy any music lover with performance beyond past offerings by other Brands with their own Compromises!

 

RE: Too Much Choice?, posted on October 23, 2021 at 11:25:41
cawson@onetel.com
Audiophile

Posts: 2378
Joined: September 27, 2004
 My horn speakers are "turnkey" as you describe - well-designed speakers from a respected builder. The latest Avantgarde range have their XD software that enables DSP for the bass as well as a bewildering selection of XO technologies.

Unfortunately they don't include a calibrated microphone and response-measuring software or the "auto-adjust" DSP offered by amps that include Dirac RoomPerfect, MARS or Anthem. However, I've found these DSPs all seem to take away a little of the top-end sparkle that I get from Avantgarde speakers - and I have a theory for the reason why.

 

RE: I don't have a Sine Wave Generator, posted on October 23, 2021 at 22:33:56
KanedaK
Audiophile

Posts: 2519
Location: Brussels
Joined: April 27, 2010
 Plenty of pink noise tracks on YouTube, also ;)

 

RE: Too Much Choice?, posted on October 24, 2021 at 20:05:37
mnawaz3@aol.com
Audiophile

Posts: 502
Joined: March 28, 2002
 from people whose ears i trust and who are familiar with danley systems, and my biases.. the opinion is that they are not going to work for me. i missed my opportunity to hear them a couple of times . and now doubt i am going to get a chance to hear anytime soon (NM is not North-east). basically i am looking for a modernized A5 type system -- without the flaws and limitations. danley systems would be a different animal.

 

RE: Too Much Choice?, posted on October 27, 2021 at 08:09:48
claudej1@aol.com
Audiophile

Posts: 817
Location: Detroit
Joined: August 17, 2007
 They are a different animal alright. And quite a spoiler at that. about 7 years ago, I started buying the original TD-1 from made by one of Tom Danley's former companies, now out of business. They had a 40x60 degree coverage patter used twin 12" Eminence drivers, 4 5" midrange drivers, and B&C DE-25 tweeters at the Apex. All in a sealed Conical Horn enclosure.

I eventually bought 20 of them, sold off 16, and kept the most "deluxe" 4 of them that were wired for single, bi, or tri amping.

They were designed to be used in pairs per channel to get mutual coupling, and double the mouth size. Use the way, you got an 80x60 pattern, and if you corner loaded them, they got down to about a flat 60 Hz. that way. 4 12" woofers per channel, the IM distortion was ridiculously LOW, as you can imagine, and you could easily EQ them to 40 Hz.

My front 3 channels for my Atmos HT setup uses 3 of his flagship SH-50's which have even better woofer and tweeter drivers, a crossover that is a work of Art in itself, and used in corners, you have to EQ OUT the excessive bass you get. No joke. My Yamaha Pre Pro then selects a 40 Hz. crossover point to the 2 "speaker stand" tapped horn subs underneath, Also, the center channel SH-50 makes a very good 4K OLED TV stand!! LOL.

I will soon replace the Klipsch Forte and Super Heresy (my own ported bass and tweeter mod) surrounds, and get those 4 up on the ceiling to replace the 2 way Klipsch KPT-200's up there now. I much prefer 3-way horn systems with the only compromise being the Bass Reflex part.

Having Hemispherical Sound envelopment is expensive the Law of Diminishing Returns comes into play as soon a you achieve 5.2 in HT. But the quest continues..................eventually, it will be ALL Danley products, but living on a pension takes more time than working folks.

 

RE: Too Much Choice?, posted on October 28, 2021 at 12:01:12
mnawaz3@aol.com
Audiophile

Posts: 502
Joined: March 28, 2002
 danley's tapped horn sub seems to be a winner. i might add that if i cant get the tht or tabletht to work.

by the way, i had no luck integrating edgars seismic subs(2) with his titan2 front midbass horns. i am told others had the same issue. bruce thought it was my 1st floor living room (19 x 17) suspended over basement. he thought a slab foundation would be better for the seismic subs . he may have been right

 

RE: Too Much Choice?, posted on October 28, 2021 at 12:28:42
claudej1@aol.com
Audiophile

Posts: 817
Location: Detroit
Joined: August 17, 2007
 Mine is on concrete floor in basement. I had it as a rear sub upstairs as a companion for the other 2, but I never adjusted or measured it. I just wanted to make sure it worked before I started coating all 3 of the cabinets with Spar Urethane. There's nothing worse than having RAW Birch lumber to absorb dirt and fingerprints, etc. for 18 years, like mine did. I became well acquainted with a rotary sander!

I finally measured mine last night. The companion amp has 2 different boost frequencies. The lower of the two is better. There's a 60 Hz. hump in my room, which my Pre Pro's Room EQ takes care of. But in raw form, the Seismic has useable response -6 db down to 25 Hz. after the boost in the amp only. The amp also has a 90 Hz. low pass filter, which is approximately the R and L horn cutoff based on the 3 ft. length at 1/4 wave. In the empty slot it left behind upstairs, I will have 'mini" re-folded, 22 ft. Gjallarhorn with twin 12" TC Sounds monster drivers (no longer made) which should put out twice as much sub bass as my old Danley DTS-10's which were BEASTLY down to about 13 Hz.!!

Next I will measure the RAW Seismic horn response at the mouth, bypassing the companion amp, as shipped by Dr. Edgar (presumably since I got this used after he passed this year).

 

RE: Too Much Choice?, posted on October 28, 2021 at 18:56:09
mnawaz3@aol.com
Audiophile

Posts: 502
Joined: March 28, 2002
 yeah, i have been on lookout for TC Sound drivers. they are rare

 

RE: Too Much Choice?, posted on October 29, 2021 at 09:27:53
claudej1@aol.com
Audiophile

Posts: 817
Location: Detroit
Joined: August 17, 2007
 I have 2 brand new in BOX I got at 1/2 off when Parts Express blew them out about years ago. The purchase was inspired by Josh Ricci of Data-Bass.com fame.

He was able to double the output of a Danley DTS-10 by using those drivers instead of the factory ones.

He also designed the Gjallarhorn, which I simulated in it's slim form and those drivers are perfect for it. My parts await assembly this winter and I have a few Crown K2's that will drive them to House Wreckin Levels if need be. Likely NOT, but I am after effortless and bottomless low bass for HT with this cab in the Rear of my room to complement the TWIN Danley TH-50's in front.

Yes, it will "scare strangers" (a Tom Danley quote) with the right LFE material from Modern Blue Ray Atmos Audio.

 

RE: Too Much Choice?, posted on November 3, 2021 at 08:02:27
mnawaz3@aol.com
Audiophile

Posts: 502
Joined: March 28, 2002
 ok, let me know when you decide that TC sounds need a new home.

 

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