How i voiced my open baffle speakers

Hari Iyer

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Around 3 weeks ago i had modified my DC KT88 monoblocks to remove the DFFF (# chokes) from the driver powersupply and substitute them with 2 small ferrite bead. I also added a ferrite bead on the driver and mains cathode resistor. This had a significant improvement in sound stage and i was more than happy with the outcome.
I was listening to the setup with my 20 year old vitrified ceramic flooring which is very common in most homes over here. But last week, i modified my damaged vitrified ceramic flooring with a laminated wooden flooring and had assembled everything in my setup like before and finally played music last Monday. It was a shocker for me. The happiness were all gone and the music sounded very sterile and without any energy and lots of roll-off (as per my listening). There was no change in the amplifier, speakers, cables, IC etc etc and the only change was in the flooring - changed from vitrified cermaic to laminated wooden flooring.
FMs who believe that flooring (or room) don't matter have either not done any homework or just lying. My elder brother had warned me that you may have to redo your crossover after the new flooring installation - though i did not believe him and told him the change would be minor not requiring any crossover modifications.
Below are the measured results of both the floor type with everything else being same other than the flooring-



Vitrified Flooring.jpg

Below is with the measurements of the same setup with a laminated wooden flooring. All speakers and microphone at the exact same location.


Laminated wooden flooring.jpg

If you notice, there is a -5dB loss of frequency respones from around 1kHz onwards till 20KHz. There is a significant improvement in the midbass region from 100Hz to 500Hz which usually is very difficult to correct. This explained why the music lacked energy and was sounding sterile.

Neverthless the rest of the week was utilized by me to do this correction for the loss of energy from the music. I modified the crossover to get the below,

Modified-Laminated wooden flooring.jpg

The hump in the response around 500Hz can be ignored as its because of the parabolic diffuser that i have used. I dont get this hump at the sweet listening spot or my usual listening position on the sofa. This modification restored my HF response and added the energy that was lacking in my setup with the flooring change. Now the speakers are undergoing break-in after the new crossover components on them. Hope to complete the break-in within a month.

Thanks for looking.
 

Hari Iyer

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Joined
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Messages
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Yesterday I had replaced my stock resistors in my passive LPF with Intron 1% thin film resistors, in the process messed up with the wiring phase and have screwed up the centre image. The passive DAC sound very fatigued and out of phase due to this. This was confirmed by playing music from my laptop. Need to fix them though not very easy due to large number of wiring to trace, but possible.
 

sdk

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Sep 28, 2014
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Around 3 weeks ago i had modified my DC KT88 monoblocks to remove the DFFF (# chokes) from the driver powersupply and substitute them with 2 small ferrite bead. I also added a ferrite bead on the driver and mains cathode resistor. This had a significant improvement in sound stage and i was more than happy with the outcome.
I was listening to the setup with my 20 year old vitrified ceramic flooring which is very common in most homes over here. But last week, i modified my damaged vitrified ceramic flooring with a laminated wooden flooring and had assembled everything in my setup like before and finally played music last Monday. It was a shocker for me. The happiness were all gone and the music sounded very sterile and without any energy and lots of roll-off (as per my listening). There was no change in the amplifier, speakers, cables, IC etc etc and the only change was in the flooring - changed from vitrified cermaic to laminated wooden flooring.
FMs who believe that flooring (or room) don't matter have either not done any homework or just lying. My elder brother had warned me that you may have to redo your crossover after the new flooring installation - though i did not believe him and told him the change would be minor not requiring any crossover modifications.
Below are the measured results of both the floor type with everything else being same other than the flooring-



View attachment 71578

Below is with the measurements of the same setup with a laminated wooden flooring. All speakers and microphone at the exact same location.


View attachment 71579

If you notice, there is a -5dB loss of frequency respones from around 1kHz onwards till 20KHz. There is a significant improvement in the midbass region from 100Hz to 500Hz which usually is very difficult to correct. This explained why the music lacked energy and was sounding sterile.

Neverthless the rest of the week was utilized by me to do this correction for the loss of energy from the music. I modified the crossover to get the below,

View attachment 71580

The hump in the response around 500Hz can be ignored as its because of the parabolic diffuser that i have used. I dont get this hump at the sweet listening spot or my usual listening position on the sofa. This modification restored my HF response and added the energy that was lacking in my setup with the flooring change. Now the speakers are undergoing break-in after the new crossover components on them. Hope to complete the break-in within a month.

Thanks for looking.
Have you considered active crossovers instead?
 

Hari Iyer

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Have you considered active crossovers instead?
Shall never go active for couple of reasons,
- vintage drivers and with high sensitivity
- more amplifiers required. I am using a 2 watts+ 2 watts DC SET monoblocks
- active crossover have many active/ passive components that can colour your sound unless you go for an extreme end design.
 

Hari Iyer

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Messages
3,591
Points
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Location
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Finall
Yesterday I had replaced my stock resistors in my passive LPF with Intron 1% thin film resistors, in the process messed up with the wiring phase and have screwed up the centre image. The passive DAC sound very fatigued and out of phase due to this. This was confirmed by playing music from my laptop. Need to fix them though not very easy due to large number of wiring to trace, but possible.
Finally resolved this issue by redoing the entire wiring. Consumed almost 5+ hours of my time.
 

Hari Iyer

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Messages
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Location
Mumbai
Finally completed all phasing issues in my source and speakers. No room treatment only a small parabolic diffuser in the first reflection point which comes into affect when I sit in my sweet listening spot. Also I have completed my digital Chain. Now have to start my analogue chain from tomorrow.
 

drlowmu

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Oct 28, 2020
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Warrensburg, Missouri
9-17-2022


Hari,

I want to THANK YOU for so actively reporting on your audio adventures to those of us who are interested in following along !!!

My one reservation is............ I am hesitant to take the word you provide to us as to what you hear and / or measure in Thane, with out conservatively having a second trusted-to-me source who will " back up " what you report to us all on your own.

Especially this is so in light of all the many system changes you now seem to make. And in light of the audio-truthful legacy I hope to leave into the future while sharing my UNIQUE direct set of audio experiences.

I now have had ALTEC PROFESSIONAL speaker-level listening experience since I was one week old - for 77 plus years. I trust what I discern for myself, audio-wise.

Dennis Fraker , my Audio mentor has VAST professional audio level equipment experience due to his unique age and home town. Dennis was born and raised in Billings, MT, which was the main service center for the then-monopoly, Western Electric in the USA. The corporate Western Electric facility in Billings Montana was sprawling........ SIX square BLOCKS big !!

The Engineers took a genuine liking to Dennis, who would ride to W.E. after school on his two wheeler bicycle, , and they often GIVE him almost anything they could..

Dennis actually OWNED his first Movie Theatre - once he graduated High School.

He spent about 50 years IN the Movie Theatre business., as a traveling Movie Theatre technician in the USA and Canada. His typical upgrade was to sell off the tinny-sounding Western Electric tube amps and sound equipment to the Japanese, and replace it with better performing optics and ALTEC VOTT Electrronics. " Out with the curl horn, IN with the ALTEC VOTT . "

So Hari, I just want to explain that I will tend to pay much attention to someone with Dennis' experience, over five decades' worth professionally, , VS what we two presently are doing, as an amateur.

I have never even heard your 2020 KT88 SE DC amps. I did travel to 11 out of 12 Rocky Mountain ( Denver ) Audio Show years, to spend a weekend previewing Dennis' systems, which varied from year to year.

Do not be discouraged with me Hari. We two each have the advantage of experiencing new things directly. It has taken ALL this time, to figure out HOW and WHY I like what I get RIGHT NOW in audio, ....after a LIFE-LONG search for personal satisfaction.

Jeff
 
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