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To Bi or not to Bi, that is the question..

165.225.68.49

Posted on July 2, 2015 at 22:15:12
pix
Audiophile

Posts: 411
Location: sweden
Joined: March 18, 2006

Hi
I have built these Karlson K15 cabs whith Beyma 15P80FE woofers (101dB/W driver senistivity). And a pair of 200Hz Tracstric horns with Radian 750 drivers (112dB/W sensitivity). I am not sure about the room/box/horn gain added.

For not loosing the 9dB difference in senistivity I figure a Bi-amp system would be very apealing. So my plan was to use my 300B SE tube amp (2x8W) for the horns, and a SS-amp (2x80w) or a Dynaco SCA-35 PP-tube amp (2x18W) for the bas woofers.
To get this working I have bought a miniDSP to be able to set the x-over and phase alignments easyly.

But this digital box (miniDSP) doesnīt "feel right" in an all analog system.

Which way would you guys go in this system ?
1. Bi-amp with a digital DSP in the system (using the drivers full sensitivity)
2. Making a analouge passive filter, using only the 300B SE tube amp (wasting 9dB senistivity in the horns)
3. Other sugestions?

 

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RE: To Bi or not to Bi, that is the question.., posted on July 2, 2015 at 22:40:27
belyin
Audiophile

Posts: 1285
Location: New Orleans
Joined: November 1, 2003
Do you have an idea of the LF roll-off of the horn? I use the Mini-DSP to make a second order low pass filter to my bass bins while allowing the natural roll-off my Oris 150 horns to make the high pass filter; maybe this could work for you as well?

 

Yes, it is called an active crossover, posted on July 3, 2015 at 07:15:25
Chip647
Audiophile

Posts: 2653
Location: The South
Joined: December 24, 2012
You need to split the frequencies prior to going to each amp. There are tube crossovers that work well. You can even do passive, see link. (Marchand sells both, no connection)

Erno Borbely used to have some great discrete crossover designs. He was a genius.

 

RE: To Bi or not to Bi, that is the question.., posted on July 3, 2015 at 07:49:55
Saturntube
Manufacturer

Posts: 331
Location: Austin
Joined: April 21, 2006
Those 200hz horns should go down to around 350 hz. It is still too high IMHO to biamp with DSP. Loose the 9dB it will sound better. Active Xovers have a BIG insertion loss.
OR Biamp with two 300B amps.

 

RE: To Bi or not to Bi, that is the question.., posted on July 3, 2015 at 08:06:38
Transformer attenuated mid horn use 1 amp to run speaker

 

There is the B4 by First Watt using JFETs, posted on July 3, 2015 at 09:57:59
JoshK
Audiophile

Posts: 820
Location: NJ/NYC
Joined: August 3, 2001
http://www.firstwatt.com/b4.html

I am not sold on tubes being better than JFETs in this particular application, especially low current 12AX7.
----------------
"When Khruschev said "we will bury you" I don't think he meant with surplus parts." zacster

 

RE: To Bi or not to Bi, that is the question.., posted on July 3, 2015 at 10:47:48
Caucasian Blackplate
Industry Professional

Posts: 8313
Location: Seattle
Joined: June 18, 2004
At 112dB, you're likely going to want to pad your tweeters down anyway, as any tiny little bit of noise coming out of your amplifier will be stupidly loud.

101dB sensitive woofers aren't going to need more than a couple of Watts anyway, so some losses in a passive crossover are acceptable.

You could also do a tube active crossover, though the passive option may work better depending on how you have the mini DSP setup.

 

RE: To Bi or not to Bi, that is the question.., posted on July 3, 2015 at 12:37:05
pix
Audiophile

Posts: 411
Location: sweden
Joined: March 18, 2006
No, so far I haveīnt made any measurements at the horns.

Perhaps a silly question, but as far as I understand, you let the HF drivers work below the horns acoustical cut off.
Couldīnt this demage the drivers caused ny to long diagraphm extrusion (caused by no acoustical diagraphm loadig)?

 

RE: To Bi or not to Bi, that is the question.., posted on July 3, 2015 at 13:07:53
belyin
Audiophile

Posts: 1285
Location: New Orleans
Joined: November 1, 2003
Not silly at; it was I who was not paying attention. The Oris Horns use a full-range Lowther speaker driver not a compression driver so I don't have the problem you would running a compression driver full-range.

 

KISS rules in audio..., posted on July 3, 2015 at 16:59:48
drlowmu
Manufacturer

Posts: 9730
Location: East of Kansas City
Joined: January 10, 2005
Nice looking set up. Very good.

Use option two !! A single amp with a top-quality parts for a passive crossover and really GOOD wiring from crossover to drivers !!!

Get rid UN needed DSPs, ADDED active stages to biamp, dis-similar amps, etc.

Also, you didn't ask, but I would advise to get rid of your SE 300B and build a two stage direct coupled 2A3 or Type 45 amp for your home system. Have fun.

Regards,

Jeff Medwin

 

RE: To Bi or not to Bi, that is the question.., posted on July 3, 2015 at 19:25:09
Rod M
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  Since:
March 1, 1999
Yes, you need at least a capacitor on the tweeter to cut off bass frequencies. A resistor will pad the tweeter down and then a coil for the woofer. Getting the right values is easy once you pick a crossover point.

Adding a SS amp and DSP could be worse than just using one 300B amp and at 101db, it should be plenty loud enough.

-Rod

 

RE: KISS rules in audio..., posted on July 3, 2015 at 22:56:43
pix
Audiophile

Posts: 411
Location: sweden
Joined: March 18, 2006
Thanks Jeff
A #45 SE amp could be my next project, ones I get the speakers up and running. My 300B amp is quite close to Jack Ellianos DRD design: http://www.electra-print.com/300bdrd.php But with a 6C45 driver tube, nickelcore parafeed OPTīs, and separate PSUīs for each chanel. I think this is a pritty neat design even though a #45 is a better sounding tube.


 

RE: To Bi or not to Bi, that is the question.., posted on July 3, 2015 at 23:05:52
pix
Audiophile

Posts: 411
Location: sweden
Joined: March 18, 2006
Thanks Rod
Is there any calculator tool out there to be used for such a calculation?
Lets say I start of with a 350Hz x-over point (12dB-slope) and a 9dB padding for the weeter

 

RE: KISS rules in audio..., posted on July 4, 2015 at 03:23:35
drlowmu
Manufacturer

Posts: 9730
Location: East of Kansas City
Joined: January 10, 2005
Well, you and I have different ideas and experiences on what is a "pretty good" design. Its gotta be WAY better than that Pix. You only THINK you have it covered.

There is MUCH more to building an amp than copying a schematic, and passing a signal, to get an ideal result.

Amps are the biggest weakest link in high efficiency audio. I have been building DHTs ( 2A3s ) Pix, since 1982, and I know they are the weak link.

Jeff Medwin

 

Of course, posted on July 4, 2015 at 03:30:25
drlowmu
Manufacturer

Posts: 9730
Location: East of Kansas City
Joined: January 10, 2005
Google is your friend. Search words as follows " R-C calculator ".

Kloss, myself, and one other have told you to KISS, throw away a DSP, etc and do a simple passive and run one really GOOD amp on system.

Why 12 dB, 6 dB is phase coherent. Can you run the woofer full range, NO degrading coil on it, and just use a C and padding R on the tweeter Pix?

KISS rules.

Jeff Medwin

 

RE: To Bi or not to Bi, that is the question.., posted on July 4, 2015 at 06:50:41
Rod M
Web Geek

Posts: 16246
Location: So. California
Joined: March 1, 1999
Contributor
  Since:
March 1, 1999
This site has several tools.

http://www.mh-audio.nl/spk_calc.asp

http://www.mh-audio.nl/att.asp

-Rod

 

RE: KISS rules in audio..., posted on July 4, 2015 at 07:51:22
pix
Audiophile

Posts: 411
Location: sweden
Joined: March 18, 2006
I hanve not copy anything...
I just wanted to give you an idea in general terms of what type of amp-toplohy I was using.

 

RE: KISS rules in audio..., posted on July 4, 2015 at 08:17:12
pix
Audiophile

Posts: 411
Location: sweden
Joined: March 18, 2006
Jeff.
I must say I get a bit amazed hearing you can tell my amp is no good just by knowing what general type of topolgy it has. Me I would not be able to tell without listening (or at least have a propper schematic) to tell.
But again, I have only 45 years in this hobby so I must have a lot to learn..

Still, my qestion was about the best way to set up my speaker x-over, not evaluating the quality of my amp (or marketing other amps). So I prefer we stay bu that.

 

Acoustical measurements or datasheet?, posted on July 4, 2015 at 10:47:42
pix
Audiophile

Posts: 411
Location: sweden
Joined: March 18, 2006
Kiss has been my goal so far, so if you think I can get good results with fewer parts Iīm eager to try.

Is your advice to made an acoustical measurement of the bass respectivley topp, and from that design my x-over, or shall i use the transucer datashet data?

Acoustical measurement is not my best of knowledge, but I have a friend whom I think I can get help from.

 

RE: To Bi or not to Bi, that is the question.., posted on July 4, 2015 at 12:13:22
del

 

RE: To Bi or not to Bi, that is the question.., posted on July 4, 2015 at 12:39:58
pix
Audiophile

Posts: 411
Location: sweden
Joined: March 18, 2006
Both
I play cdīs and Vinyl recoards

 

RE: To Bi or not to Bi, that is the question.., posted on July 4, 2015 at 14:30:37
tomservo
Manufacturer

Posts: 8212
Joined: July 4, 2002
The text book approach only works if you have a resistive load.

Most loudspeakers have an impedance that changes with frequency and has capacitive and reactive elements so a crossover program like LSPcad or other will give more accurate results so far as producing the desired response / finding the right values.

 

Warning. Don't expect Jeff to..., posted on July 4, 2015 at 21:10:46
91derlust
Audiophile

Posts: 1101
Joined: December 25, 2014
listen to what your needs are and provide relevant advice. He is very much into his thing... but it may not be your thing.

You are into some cool stuff. Experiment. Have fun. Enjoy!

Regards,
91.

"Confusion of goals and perfection of means seems to characterise our age." Albert Einstein

 

RE: Tis Nobler to Bi-Amp, posted on July 5, 2015 at 17:32:37
Mr_Steady
Audiophile

Posts: 2042
Location: North Florida
Joined: August 19, 2014
I say get a Marchand two-way FET crossover as a start. Sometimes on sale for $500. If you use his tube xover then you can get rid of your active preamp.

I saw your DIY build thread on the horns. Kudos to you!

Run FR sweeps of your two drivers. Get the calibrated mic if you don't have it.

Your system would benefit from bi-amping more than most.


---------------------------------------------------
Big speakers and little amps blew my mind!

 

RE: To Bi or not to Bi, that is the question.., posted on July 6, 2015 at 05:03:24
Cut-Throat
Audiophile

Posts: 18286
Location: Minneapolis - St.Paul Area
Joined: September 2, 2000
Contributor
  Since:
May 16, 2021

This is a Picture of my Plate Amps in the Paduak Wood Cabinet that I made for them....

Bi-amping was one of the best Bang for the buck upgrades I've done. I bought a pair of Hypex Class "D" amps (Link Below). They have an active crossover built in and are 400 watts per channel apiece, and I have them bridged.(So, plenty of power to the Bass Bins) The pair cost about $800 (very cheap route to go). I have them hooked to a Khorn Bass Bin with an Oris Orphean Horn System on Top driven by a pair of Welborne Monoblock 45 SET amplifiers. Just Outstanding!

I first used them with an Altec Multicell 1005B Horn and Khorn Tweeter and they worked well there also.

I tried a Marchand, but the increase in wires, plus the cost and extra amps was a lot more complicated and subject to more ground loops.




 

RE: KISS rules in audio..., posted on July 9, 2015 at 07:06:22
drlowmu
Manufacturer

Posts: 9730
Location: East of Kansas City
Joined: January 10, 2005
Pix,

" I must say I get a bit amazed hearing you can tell my amp is no good just by knowing what general type of topolgy it has. "

Not amazing at all. You may have 45 years, but Pix, I grew up listening to a pair of ALTEC 604 Bs sixty two years ago - in my parent's Recreation Room. I built my first DIY DHT 2A3 amp in 1982.

I came to the conclusion by now, ( from my direct listening experience on high efficiency speakers ), no one will do better than a PROPERLY made two stage DC SE amp, typically with a mu of 100 driver tube, connected to the grid of either a Type 45 or a 2A3. Others, may have to learn that, assuming they knew how to build the amp really well. Often that is a large assumption, from what I see.

IMHO, amps, not speakers, are the weak link in audio, " the turkeys " and in high efficiency audio particularly. YMMV, this is perfectly OK with me !! Have fun.

Jeff Medwin

 

RE: Acoustical measurements or datasheet?, posted on July 9, 2015 at 07:12:49
drlowmu
Manufacturer

Posts: 9730
Location: East of Kansas City
Joined: January 10, 2005
Pix,

The calculators are on line, many sites offer them. I design primarily by ear, since in the end, what we hear is what counts. You can learn the theory, fine, but its only theory, TRUST what you hear for yourself. In the end result, " how it sounds to " YOU " is ALL that matters " !!

Be happy, have fun.

Jeff Medwin

 

RE: There is the B4 by First Watt using JFETs, posted on July 9, 2015 at 09:05:55
Mr. Lowther
Distributor or Rep

Posts: 115
Location: Chicago area
Joined: November 26, 2001
Have this, it is a great crossover just for uses like this. Extra advantage of readily changeable crossover frequencies and slopes, so you can easily see what sounds best for your speaker. Not married to a single frequency & slope like many other analogue crossovers.

Jon Ver Halen

 

RE: To Bi or not to Bi, that is the question.., posted on July 11, 2015 at 15:28:08
hollowboy
Audiophile

Posts: 263
Location: Melbourne
Joined: June 26, 2007
I'd suggest finding out for yourself what works for you - run signal through the DSP with it set to flat. Blind test if possible (get someone else to switch the DSP in and out).

If you can't hear any degradation of sound, then use it. Enjoy the flexibility and simplicity of setting everything up with a few mouse clicks.

Maybe stick the DSP in a 15kilo box with dim light bulbs on top so it does "feel" right.

 

RE: KISS rules in audio..., posted on July 13, 2015 at 19:09:35
Don Reid
Audiophile

Posts: 891
Location: Rural NW Georgia
Joined: February 2, 2001
Contributor
  Since:
April 1, 2010
Different strokes for different folks. The best sound I have ever had is my present rig with Bill F's HT Tuba corner horn subs, Oris 150 horns with AER MD-3 drivers and Fostex t900a bullet tweeters. I tri amplify with a DEQX HDP-3 DSP. Amplifiers are an old modified NYAL Moscode 600 for the woofers and two Nelson Pass built First Watt F3 JFET stereo amps for the mids and tweets. The First Watt SS amps replaced Cary Audio 2a3 monoblocks. That change was a real improvement.

It took me a very long time to get all the elements to play well together, but now that they do I can't imagine a KISS system sounding as good to me.
I dream of an America where a chicken can cross the road without having it's motives questioned.

 

RE: KISS rules in audio..., posted on July 15, 2015 at 17:36:15
Mr_Steady
Audiophile

Posts: 2042
Location: North Florida
Joined: August 19, 2014
That's a very sweet set up. I've been wanting to try the F3's. What are your crossover points? Do you feel like your Oris horn comes across like a point source?

When I was running my mid horn from 400hz to 6000hz I couldn't even tell the tweeter was working. It sounded like the mid horn was doing every thing but the deep bass. Of course this is on-axis.



----------------------------------------------------------
Big speakers and little amps blew my mind!

 

RE: To Bi or not to Bi, that is the question.., posted on July 15, 2015 at 17:50:29
Mr_Steady
Audiophile

Posts: 2042
Location: North Florida
Joined: August 19, 2014
>"At 112dB, you're likely going to want to pad your tweeters down anyway, as any tiny little bit of noise coming out of your amplifier will be stupidly loud."

CB I have to tell you I've run the 2a3 Stereomour directly connected to my mid horn/driver, and no noise, even with AC on the filaments.

Makes me question the need for complicated DC filament supply arrangements. Well, I know the need, Audiophiles who must simply have the blackest of black backgrounds.


------------------------------------------------------
Big speakers and little amps blew my mind!

 

My first try was.., posted on July 19, 2015 at 22:12:24
pix
Audiophile

Posts: 411
Location: sweden
Joined: March 18, 2006
Last evening I figure Iīll try the simplest x-over of them all.
A 350Hz (6dB/Oct) hipass to the horns, and let the K-15 roll of naturally (mechanically). My 300B SE-amp feeding the horns and an SS-amp feeding the K-15īs.

Sure, there is a long way further to go, must admit I was suprized how good they sounded already. Especilly I was very satisfyed with the open and airy sound from the horns, indicating no need of adding a topptweeter.

Now, at least I have a staring point

 

RE: To Bi or not to Bi, that is the question.., posted on September 1, 2015 at 11:07:04
mnawaz3@aol.com
Audiophile

Posts: 502
Joined: March 28, 2002
for me, bi-amping produced a more balanced sound. I got more detail and better bass (without bi-amping I got a comfy midrange sound).. the downside is that it was more difficult to get rid of the notch ( once you hear the notch, you wont stop hearing it). I found a tricked out marchand tube xover was much better than the pro style gear. eventually after a few yaers of effort I got close to what I wanted. and then life changes happened.

 

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