FR graphs of Danley Unity Horn

keto · 04:35 AM

Here are my most typical readings, with the original mids and BMS 4550 compression driver.

Each pass band will have its own (SET) amplification.

The peak on the BMS 4550 driver at 750hz will be reduced by tuning two coupling capacitors within the corresponding amplifier to that frequency.

head_unit · 7th February 2012, 05:32 AM

Cool! But I'm kinda confused (maybe due to not super familiar with the Unity).
- Why is the distortion smoothed? One of the problems with distortion is often very narrow peaks.
- How come the distortion and magnitude plots seem like different drivers?

keto · 7th February 2012, 12:40 PM

I'm just getting familiar with the measuring equipment. The top plot is the magnitude of the mids, with harmonic distortion. The bottom one is the SPL of the tweeter.

keto · 16th February 2012, 02:48 PM

Here are some more measurements of 1) the mids, at close range (1-2ft), all on-axis, with different volume and mic settings and 2) the mids with and without a 1st-order HP @ 300hz. All graphs were chosen for their lowest harmonic distortion.

keto · 2nd May 2012, 02:09 AM

I've just made the first modifications of a Bottlehead S.E.X. (2W, 6DN7-based) amp to drive the BMS 4550 in a Unity Horn. The interstage and output (parafeed) coupling caps are tuned to give high-passes of around 900hz, and a step filter was added to the input to give a 12dB compensation between 2khz and 10khz.

I'll let it all burn in for a while and measure again later.

keto · 4th May 2012, 02:04 AM

I've swapped back in the original B&C DE25 tweeters, with their time-aligned passive crossovers. What a great sound! This will be my benchmark as I work out the filters for the BMS 4550 and TAD TD2001. There was an issue with one of the BMS drivers, so they're on their way back to Germany, and the TADs are in Chicago... so the B&Cs will be in for a while now.

Here are their L and R frequency plots, taken with the mic at the mouth of the horn.

hunter audio · 4th May 2012, 06:56 AM

Hi Keto

Could you please advise on your measurement set up .

keto · 4th May 2012, 01:04 PM

Earthworks mic, Motu Traveler pre, FuzzMeasure and a Macbook Pro. Mic was at the mouth of each horn for the last one, and levels were adjusted until I got consistent readings with lowest distortion. Tweeter is being fed by a Bottlehead 2W SET amp.

hunter audio · 5th May 2012, 06:26 AM

Thanks

keto · 01:14 AM

Here are graphs of:

a single mid vs. parallel quartet

and parallel vs. series-parallel quartet.

Hmmmm, must do something about that 4K peak.

7th February 2012, 12:48 AM	#1
keto diyAudio Member Join Date: Jul 2010	FR graphs of Danley Unity Horn Here are my most typical readings, with the original mids and BMS 4550 compression driver. Each pass band will have its own (SET) amplification. The peak on the BMS 4550 driver at 750hz will be reduced by tuning two coupling capacitors within the corresponding amplifier to that frequency. Last edited by keto; 7th February 2012 at 04:35 AM.

7th May 2012, 01:09 AM	#10
keto diyAudio Member Join Date: Jul 2010	Here are graphs of: a single mid vs. parallel quartet and parallel vs. series-parallel quartet. Hmmmm, must do something about that 4K peak. Last edited by keto; 7th May 2012 at 01:14 AM.

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7th February 2012, 05:32 AM	#2
head_unit diyAudio Member Join Date: Feb 2004 Location: Los Angeles	Cool! But I'm kinda confused (maybe due to not super familiar with the Unity). - Why is the distortion smoothed? One of the problems with distortion is often very narrow peaks. - How come the distortion and magnitude plots seem like different drivers?

7th February 2012, 12:40 PM	#3
keto diyAudio Member Join Date: Jul 2010	I'm just getting familiar with the measuring equipment. The top plot is the magnitude of the mids, with harmonic distortion. The bottom one is the SPL of the tweeter.

16th February 2012, 02:48 PM	#4
keto diyAudio Member Join Date: Jul 2010	Here are some more measurements of 1) the mids, at close range (1-2ft), all on-axis, with different volume and mic settings and 2) the mids with and without a 1st-order HP @ 300hz. All graphs were chosen for their lowest harmonic distortion.

2nd May 2012, 02:09 AM	#5
keto diyAudio Member Join Date: Jul 2010	I've just made the first modifications of a Bottlehead S.E.X. (2W, 6DN7-based) amp to drive the BMS 4550 in a Unity Horn. The interstage and output (parafeed) coupling caps are tuned to give high-passes of around 900hz, and a step filter was added to the input to give a 12dB compensation between 2khz and 10khz. I'll let it all burn in for a while and measure again later.

4th May 2012, 02:04 AM	#6
keto diyAudio Member Join Date: Jul 2010	I've swapped back in the original B&C DE25 tweeters, with their time-aligned passive crossovers. What a great sound! This will be my benchmark as I work out the filters for the BMS 4550 and TAD TD2001. There was an issue with one of the BMS drivers, so they're on their way back to Germany, and the TADs are in Chicago... so the B&Cs will be in for a while now. Here are their L and R frequency plots, taken with the mic at the mouth of the horn.

4th May 2012, 06:56 AM	#7
hunter audio diyAudio Member Join Date: Dec 2003 Location: calcutta	Hi Keto Could you please advise on your measurement set up .

4th May 2012, 01:04 PM	#8
keto diyAudio Member Join Date: Jul 2010	Earthworks mic, Motu Traveler pre, FuzzMeasure and a Macbook Pro. Mic was at the mouth of each horn for the last one, and levels were adjusted until I got consistent readings with lowest distortion. Tweeter is being fed by a Bottlehead 2W SET amp.

5th May 2012, 06:26 AM	#9
hunter audio diyAudio Member Join Date: Dec 2003 Location: calcutta	Thanks

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