How i voiced my open baffle speakers

Hari Iyer

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How i voiced my OB speakers:

I acknowledge direct and indirect contribution of the following FMs whose opinion and/or materials helped me to voice my speakers

@drlowmu - The amplifier schematics and tips on building them, mil spec silver plated copper wires
@yogibear - 20awg gold plated solid silver wire hand crafted by his close friend
@prem - recommendations of music - Lata's voice, Nusret Fathe Ali voice, flute and piano used for voicing
@jls001 - recommendations on using male RC connectors - Amphenol

For those who have joined in late, the below link is a recommended reading if you would like to know the precursor to this post.


A little background for those who have been following my post,

The OB baffle had many iterations since i began building them almost 3.5+ years ago. I had initially planned them to use only a single 8" Russian full range driver which had a resonance of 35Hz and was a high-compliance driver (Model: 10gdsh-1-4 - Build 1955). These drivers were more suitable for a sealed enclosure because of its compliance of the suspension. When mounted on an open baffle lacked the bottom end that i was looking for. This driver rolled-off quickly from around 800Hz @-6dB/octave as there was no support for the suspension from the box. Hence i went ahead later adding a H-frame OB sub-woofer with initially Dayton Audio 10" woofer which had a resonance of 24Hz but the compliance was a bit higher around 0.6mm/Newton. The low end though present was a bit loose not to my liking. I used to cross them at around 150Hz but again there were serious dip between 150Hz to around 600Hz which needed to be addressed.

I was looking for a good mid-bass driver within my budget and stumbled upon the Sachenwerk field coil driver which were from the pre WWII era (build in 1938) which has a phenolic spider on them. This was mostly a mid-range driver having a rising response from 100Hz till 3KHz with a very good cone breakup modes after that. I operate them on 70VDC field energy which is roughly around 5.2watts. This driver addressed the mid-range issue but still not good for the mid-bass from 100Hz to 400Hz region which though covered by my sub-woofer but causing some directional issue. I later changed the driver on my H-frame sub-woofer from Dayton Audio to a vintage re-coned Bolton driver from 1985 which had very low compliance for the suspension (0.18mm/Newton) and a resonance of around 50Hz. This driver gave me the correct tight bass and extension that i was looking for and allowed me to cross-much lower around 70Hz which was not possible with the Dayton driver.

I later purchased an Ahuja 12" woofer to address the mid-bass issue but this woofer was disaster as it was never been able to be driven by my puny 3+ 3 watts DC KT88 amplifier as this was a pro-woofer with high mass paper cone and compliance around 0.3mm/Newton. 2 months ago I replaced the Ahuja 12" with an Clevland 12" Alnico woofer which were salvaged from a church organ build around 1962. In the meanwhile i had also bought an Telefunken 3" Alnico tweeter from FM @yogibear 2 years ago which were unused due to matching with the other drivers (btw i have been using them now - more about this later)

Though i had many iterations of using these drivers by connecting them sometimes direct and sometimes with an crossover network etc never went ahead to voice them so intensely like last 2 weeks. I had fixed an budget for the voicing which should not exceed 5000/- bucks as anything more than that was not viable for me as it would have been more trial and error.

The Open Baffle design has some artifacts that was meant to cater to the room equations as below,

- The parabolic reflector on both the 8" drivers allowed in early reflections by diffusing the rare waves from them there by simulating the room like an auditorium kind of effect. This has a significant improvement on the mids to upper-mids end by having the right delay between the direct and reflected sound and hence the need of any room treatment is avoided
1648376483708.jpeg

- The Telefunken Alnico tweeter is now added to the vertical plane giving a very good overall directivity till the top-end and a more omni-directional sound beyond 4KHz +

1648376552216.jpeg


These were the crossover network prior to the voicing 2 weeks ago

1648376596337.png

These were the measured response with this crossover 2 weeks ago,

1648376639180.jpeg

Voicing process followed:

Before i started with correction of the crossover, i was supplied by an extra length of around 3 meter wire by drlowmu primarily to replace the RW20 softone output transformer wires with them. @drlowmu believed that the original softone wires were puny (indeed they are) and does not handle transients very well. First thing i did 10 days ago was parallel the existing primary and secondary wires with the mil spec wires supplied by @drlowmu. Even with this simple mod, i got a better high-end response, much details and much transparency. Needless to say that - proof of the pudding is in its eating and not waste time debating on the forum needlessly.

I had a goal of having a measured response on-axis within +/- 1.5dB between 100Hz till 10KHz which first needed to be corrected before i could begin voicing. I modified the above crossover to this.

1648376727468.png

Below is the measured response with this crossover last week after flatenning the response from 100Hz till 10KHz,

1648376762269.jpeg

While listening to Lata's voice and flutes, i noticed that subjectively they sounded a bit metallic and more sweeter than required. Some flutes (Hariprasad Chaurisa) in their higher octaves were edgy and not natural sounding more like listening to a speaker. I narrowed down this issue to the 100uF, 450VAC Epcos metallized polyproplene motor run capacitor that were used without any bypass capacitor. I replaced the EPCOS with an 68uF, 400VDC Mundorf EVO foil type capacitor. I added a 0.22uF, 250V , 0.68uF,250V Bevenbi MKP and an 0.01uF,100V Wima MKP capacitor across the Mundorf as a bypass capacitor. The capacitor leads were soldered with an extension of gold plated solid silver wires supplied by @yogibear. There was a significant reduction in the metallic Lata voice and the flute sounded much rounded off. Still it was sounding like a speaker and i wondered why? I believed it to be because of the 1 meter polycab telephone cable used as speaker cable. I replaced them with a Belden tin plated 12awg x 2 each polarity and found a very good balance in the mids and highs with this simple change. The original speaker wires are 12awg x 2 + 16awg x 1 mil spec wire for each polarity supplied free of cost to me by @drlowmu which is Fulton length. But unfortunately staying in a small apartment in Mumbai has its own inherent challenges and to live with Fulton length wires can be challenging with speaker placement. Hence i needed to extend this wire to suit my speaker placement. Here is where the polycabs and beldens come in. I would be happy to replace these with the mil spec wire in the future.


But again some more work needed to be done. I further wondered and later decided to replace the 3.6 ohms Raatronic inductive resistor with something different. I had purchased some manganin wire last year and made a nude wire resistor of around 4.6 ohms with them and replaced the Raatronics. The manganin wires were terminated again by the gold plated silver wire supplied by @yogibear. Also i modified the crossover a bit to not have the Russian driver the signature of any capacitor and directly connected them to ground polarity as below

1648376922060.png

This modification had an significant improvement on the impedance curve and also Lata's voice sounded very natural and the flute was no more edgy or bright and had a very natural decay of its harmonics. I later played some Piano and they too sounded very natural to my ears. As this was an open baffle, they dont have any issue of stored energy releasing later just like a box speaker. So to play Piano naturally was not a challenge due to the open box loading.


I have not yet measured the speaker after their voicing and may do so later as i dont want my subjective listening to be influenced by my measured results. But eventually i shall go ahead and definitely measure them for my learning. By this voicing and crossover modification exercise, my speaker building skills have now improved a percent up from previous 3% to now 4% (can i say this - i dont know).

Thanks for looking.

PS: Yet to purchase the Amphenol gold plated RC connector recommended by @jls001
 
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drlowmu

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Hari Iyer,

Lovely report, thank you for sharing this with F.M.s.

May I make ask a question or two, make a comment or two, maybe a few suggestions ?

In regards to your bypassing of the 68 uF EVO Mundorf main cap, did you add a 0.22, a 0.68uF and a 0.01 as you wrote .........OR was it mis- described, and really was a 68uF main cap + 0.22 + 0.068 + 0.01?????????

( Usually one describes bypassing as largest uF.... to smallest uF, but you wrote 0.68 after 0.22 uF )

Please confirm.

IF your sequence truly is 68+0.68+0.22 +.01, there exists a gap between 0 .22uF ( the middle midrange ) and 0.01 uF ( the extreme most highs ). This sequence is likely leaving an unwanted HOLE in the response, between the middle-mids and the highest of highs....in the middle-highs.

That " hole " ( 0.22 to 0.01uF ) should be filled - in some .....and listened to, with one or more values ( such as maybe 0.068 or 0.047, or a 0.033uF ), plus use a good quality 0.01 uF for the extreme top end.

LOL, please don't E.E. theorize my comments, just TRY it and listen . :)

Try this : simply listen to a single WIMA FKP-1 0.033uF at 630 VDC or 1250 VDC *, and tell us if voice and flute are even more natural sounding.

( * ) Notice how I suggest 1250 VDC for a speaker cap ? Higher voltage WIMA caps often use a thinner dilectric, .........and may thus sound a bit better .

IF, however, you actually have a 0.068 uF cap in the bypass sequence, and no 0.68 uF you will beneficially have less of a hole in the middle highs. Unfortunately, there will be a hole between the main ( 68uF EVO ) cap and the 0.22 ( midrange bypass cap ) which can detrimentally effect the mid-bass . The uF value of 0.68 is the mid-bass bypass value...and this cap needs to be a good quality cap also !

BTW, my friend, you are using the wrong Wima 0.01uF cap type Hari !!

Not the MKP type ( metalized dilecteric ) as described. Always use the inexpensive WIMA FKP-2 ( non metalized ) 0.01 uF at 630 VDC as a standard " go-to " part. It costs well under one U.S. dollar and performs about equal to the twenty dollar plus 0.01s we used to buy !!!!!

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - -- - - - - - - -- - - - --- - -


As a final comment on speaker bypassing, what is done to the woofer should also be done to the tweeter, as far as having the SAME bypass caps ( of high quality and same uF values ) in the circuit. But first, lets get the above-mentioned areas experimented by you, listened to, before proceeding to addressing the single 6.8 uF tweeter cap.

Also, with your SE DC KT88 amp having such a " quick " power supply, adding a 5 uF GTO bypass cap across the 68 uF EVO will be a total killer, in resolving leading edges of all music transients. Nothing is like it !!

I truly like the design and wood work of your open baffles sir. Bravo.

Jeff
 
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Hari Iyer

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Thanks Jeff for your views.

I have used 68uF bypassed by a 0.68uF, 0.22uF and a 0.01 uF. The choice of capacitors are more due to price and local availability. I cannot afford international shipping rates which are insane.

I may have both the 0.033uF and 0.068uF - both 1200VDC - EPCOS MKP type. Wima FKP are not available locally. Other expensive options are Orange drops 715p, Jantzen cross caps, WEET etc, but I may need to double or triple my voicing budget to purchase them.

The Telefunken tweeter uses a ,6.8uF Jantezn crosscap ( foil type) with a 0.01 uF Orange drops 715P. (foil type) as bypass.
 

Hari Iyer

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From today I have disconnected my sub-woofer from my setup due to failure in my sub-woofer power supply connection. Infact this was a blessing bn disguise. Now i am playing direct from my main OB speakers and don't have to worry about subwoofer phase shifts and room placements.

I added cardboard wings only on the 12" Alnico woofer sides on the rare to extend them from previous 4" to now 18" on both side. This prevents cancellation of front vs rear waves there by giving an additional octave of extension on the lower end. Am I missing my subwoofer? Yes and No. Yes - because I have so much been spoilt by thumping deep bass from my sub-woofer, I have some kind of withdrawal symptoms :)- TBH.

No - because the bass is natural and plays bass if its there in the recordings. Tabla and Dholak sound as if played in the room with accurate balance which was missing when using a sub-woofer no matter - how accurately i levelled them. May be without the sub-woofer the overall coherence in the sound stage has improved and is more accurate. Male voice is more natural and real without any artificial low end.
 

drlowmu

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From today I have disconnected my sub-woofer from my setup due to failure in my sub-woofer power supply connection. Infact this was a blessing bn disguise. Now i am playing direct from my main OB speakers and don't have to worry about subwoofer phase shifts and room placements.

I added cardboard wings only on the 12" Alnico woofer sides on the rare to extend them from previous 4" to now 18" on both side. This prevents cancellation of front vs rear waves there by giving an additional octave of extension on the lower end. Am I missing my subwoofer? Yes and No. Yes - because I have so much been spoilt by thumping deep bass from my sub-woofer, I have some kind of withdrawal symptoms :)- TBH.

No - because the bass is natural and plays bass if its there in the recordings. Tabla and Dholak sound as if played in the room with accurate balance which was missing when using a sub-woofer no matter - how accurately i levelled them. May be without the sub-woofer the overall coherence in the sound stage has improved and is more accurate. Male voice is more natural and real without any artificial low end.


IMHO : Most sub woofer systems I get to hear play bass all the time, when it is not even in the recorded signal. Almost like a kid's car stereo, thumping away. Nice post, and listening observation Hari !!!

Jeff
 

Hari Iyer

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During voicing of my speakers, i realized that with a series crossover tuning by ear is very difficult, because change in one component for one driver affects the voicing of other speaker due to the topology of the crossover. This was becoming increasingly difficult to tune by ear. So i changed the topology from series to parallel and went by removing all the components and began voicing all over again by not measuring anything but only by listening and fine tuning and trusting my ears as to what sounded nice to my ears.

During the process, i ended by removing all my inductors from my 8" full rangers and put both of them in series. I had to increase the topology from 2nd order to first order for the 12" Alnico woofer and added generous amount of inductance to roll-off them as they are organ speakers and have a tone suited for organs and guitar. This is the final crossover schematic that i came up with.

1649440381121.jpeg

As you can see the filter for the full-ranger is a bypass type. This is how the measured FR look like and what my ears liked listening to,

1649440615320.jpeg

There is a gentle roll-off from 2KHz onwards which is around -10dB at 12.5KHz. This agrees to what most FMs prefer as a tilt in the response from 2KHz. Below is the 1/3rd octave response for easy viewing of the same measurement.

1649440816065.jpeg

Thanks for looking.

PS: All the above measurements without subwoofer.
 
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Hari Iyer

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After completing the electrical crossover, the next level of improvements need to be achieved acoustically. When noticing the FR curve and the associated excess phase some conclusions can be drawn,
- the peak at 7kHz comes from the whizzer cones
- the peak at 1750kHz comes from left side baffle edge which aggree with my calculations
- the dip at 960 Hz is from the other end baffle edge which agrees with my calculations.
- the peak at 500 Hz looks like a floor reflection ( not confirmed)

To address the 7 KHz peak and break the HF modal frequency, I have added a sunflower shapped phase plugs to diffuse these modal frequencies. For the 1750 kHz peak I have added layer of felt at the baffle edge to absorb and damp them.

The other 500 Hz peak if they are from floor bounce will be left untouched as they don't influence very much on tonality.

The 2 peaks below 300 Hz are room modes and need to be addressed only by expensive room treatments.

Imo most of the issues ( atleast in my case) looks like issues with the baffle design or driver placement on the baffle rather than room itself. A proper analysis of the measurements and its associated solutions can be addressed by focusing on the baffle rather than going for room treatments.

I have yet to measure the speakers after these mods. It will be interesting to review the excess phase response and the associated beaming after these mods.
 
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Hari Iyer

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Last weekend spent most of the time in rewiring my speaker cables (Polycab DC solar cable - 4 sq.mm - single core). I have used 2 Fulton lengths of this wire (114.25 inch) to connect to my existing 2 Fulton length silver plated copper wire. I know this is kind of weird but again this is what DIY is all about.

Using the silver plated copper wire + 1.5 meter of polycab pure copper wire + 0.5 meter of tin plated Belden wire gave me an very extended HF response though its not bright or sibilant sounding. It depends upon if you prefer this tonality of extended highs and detailing with compromise with natural sounding. Infact i had to add inductors, capacitors and resistors as compensation to tame the extended HF energy - there by adding phase shifts by using the passive components.

Adding the tin plated copper wire, i had to literally remove all these compensation filters and now my speakers are connected directly to the amplifier with nothing in-between. Without removing the tin-plated copper wire sounded very dull and boring with severe HF roll-off. Yes the tin plated copper wire acts like an HF filter - i dont know how they will sound after 100+hrs of break-in - but out of the box they roll-off HF like a filter without affecting much of the LF. At MF they sound very flat. IMO, if your set-up is very bright and shrill the Polycab DC solar cable can be a remedy for your bright and shrill sound - without breaking your bank. The tin plating on this wire is non-glossy and will not make the HF edgy, bright or distorted. My XO schematic (well now there is no crossover) as below,

1650258539067.png

Measured response after 1 hr of listening as below,

1650258773709.jpeg
As you can see there is a natural roll-off above 4KHz and i dont require any compensation network to achieve that roll-off. Just using tin-plated copper wire achieve that. It will be interesting to note how this wire fare after 100+hrs of break-in - which means 1 to 2 months of my listening time window.

There has been a lot of debate by objectives vs subjective camps for showing the affect of wires based on measurements. Well below is the measurement of my silver plated copper wire without any compensation network.

1650259060044.jpeg

Its clearly evident that the silver plated copper wire has more MF and HF energy compared to the tin plated copper wire. I am not talking about which sounds superior to other - that's a purely a subjective choice based on the type of music you listen and what you prefer. Wires can be used as tone control is what is demonstrated here. If your setup is dull, boring and lack HF energy then perhaps using a silver plated copper wire you shall benefit. Pure copper i persume would be flat sounding and that will be another interesting experiment.

It shall be wise for FMs to stick to the brand / type of wire recommended by your speaker manufacturer as they would have 99.99% voiced their speaker using that particular brand/type of cable. If you plant to deviate from that based on the hype and mis-information about wires and cables then you need to be prepared to modify your crossover too to achieve that balance.

Thanks for looking.
 

Hari Iyer

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The Polycab tinned copper has now around 20 hrs of listening and they seem to have some better midrange balance with the highs. Them seem to settle well. Will be interesting to measure them.
 

Hari Iyer

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After 2 weeks of listening and break-in of the tin plated copper wire more than 40+ hrs of listening, did not like what i heard from this wire. The highs though in balance with the rest of the frequency seem to be laid back and not accurate. Hence i restored back everything to my silver plated copper wire and got back the symmetry. The silver plated copper wire sounds much direct, involving and keeps me engaged in my music and exiting too. Btw, i also made the below changes,

- Changed my speaker positioning from parallel wall to diagonal wall placement
- Changed my 4 year old Russian driver to a brand new Russian driver - same model nbr - but without any abuse

After the above changes i hooked them up and listened to them. Wow, i was amazed at the sound transparency, coherence, dynamics went to another level which was never heard before and i was extremely happy with the overall outcome. This was on a Friday evening and went on to listen music till late night without even realizing that it was 1AM or police will be on my door.

I went ahead just listening to the newly discovered magic next day morning and was super happy with this happening. Came late evening, i though why not try to measure them and discover how they measured. Below is what i measured- posting only the FR curve and Step response (if FMs are interested in anything else let me know)

1651401961346.jpeg

1651401987688.jpeg


it measures HORRIBLE. As you can see there is no bottom-end, no top-end and more of peaky mid-range. Anyone would discard this speaker if they look at only the measurement without listening. This made me wonder there might be something wrong with my measurement gear. The rest of the evening i again only listened to the music and late night around 12 mid-night i carefully checked all my measurement gear to see if there was any mistake in the measurement and measured again. Ditto i again got the same measurement. So nothing was wrong in the measurement. It measured again HORRIBLE. Was something wrong with my EARS? I dont think so as i was hearing my family members and neighbors exactly as yesterday. So my ears are also ok. Nothing wrong with them either.

If both my ears and measuring is accurate then whatever 3% to 4% knowledge i had gathered in the past 10+ years have to be dumped and i will have to start again from zero. What i am measuring and what i am listening does not even closely correlate. Its one of the greatest secrets in audio which i am slowly but surely realizing. I know that ARC fans will troll me and start hating me for this discovery - but again those who follow my post also know that i too am a measurement freak and this discovery has to be made public.

Will try and post a recording of the speakers (if possible) for others to decide later if there is any debate.

Thanks for looking.
 

drlowmu

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After 2 weeks of listening and break-in of the tin plated copper wire more than 40+ hrs of listening, did not like what i heard from this wire. The highs though in balance with the rest of the frequency seem to be laid back and not accurate. Hence i restored back everything to my silver plated copper wire and got back the symmetry. The silver plated copper wire sounds much direct, involving and keeps me engaged in my music and exiting too. Btw, i also made the below changes,

- Changed my speaker positioning from parallel wall to diagonal wall placement
- Changed my 4 year old Russian driver to a brand new Russian driver - same model nbr - but without any abuse

After the above changes i hooked them up and listened to them. Wow, i was amazed at the sound transparency, coherence, dynamics went to another level which was never heard before and i was extremely happy with the overall outcome. This was on a Friday evening and went on to listen music till late night without even realizing that it was 1AM or police will be on my door.

I went ahead just listening to the newly discovered magic next day morning and was super happy with this happening. Came late evening, i though why not try to measure them and discover how they measured. Below is what i measured- posting only the FR curve and Step response (if FMs are interested in anything else let me know)

View attachment 69067

View attachment 69068


it measures HORRIBLE. As you can see there is no bottom-end, no top-end and more of peaky mid-range. Anyone would discard this speaker if they look at only the measurement without listening. This made me wonder there might be something wrong with my measurement gear. The rest of the evening i again only listened to the music and late night around 12 mid-night i carefully checked all my measurement gear to see if there was any mistake in the measurement and measured again. Ditto i again got the same measurement. So nothing was wrong in the measurement. It measured again HORRIBLE. Was something wrong with my EARS? I dont think so as i was hearing my family members and neighbors exactly as yesterday. So my ears are also ok. Nothing wrong with them either.

If both my ears and measuring is accurate then whatever 3% to 4% knowledge i had gathered in the past 10+ years have to be dumped and i will have to start again from zero. What i am measuring and what i am listening does not even closely correlate. Its one of the greatest secrets in audio which i am slowly but surely realizing. I know that ARC fans will troll me and start hating me for this discovery - but again those who follow my post also know that i too am a measurement freak and this discovery has to be made public.

Will try and post a recording of the speakers (if possible) for others to decide later if there is any debate.

Thanks for looking.

Several questions Hari.

Just trying to follow and understand what you are saying above and doing.

You above say :

" The silver plated copper wire sounds much direct, involving and keeps me engaged in my music and exciting too. "

Q1) Is the " silver plated copper wire " the 12+12+14 AWG ( per polarity ) 114 1/4 inch paralleled trio of m22759/11 Military Spec wires you received in 2021 from the USA?????

Q2) If affirmative above, are you absolutely needing to add a length to them, to reach your loudspeakers???

Q3) Is this because you no longer keep your electronic equipment between the two speakers, but rather, to one side????

Q4) If affirmative to Q3 above, is this positioning a result of FM Perm's superb / break-through work on speaker placement???

A couple of additional questions arise. :

Q5) What would your total system sound like, over-all, if you re-positioned your speakers, on either side of your electronics, and were able to use JUST single 114 1/4 inch runs of uniform speaker cables, ( amp to drivers ), instead of " two different wire types connected in series " ?????

Q6) In the event that you must keep equipment off to one side of the speakers, and require longer than two Fulton lengths ( 57 1/8th Xs 2 = 114 1/4 inches ), HOW MANY Fulton lengths are needed ( times two, times three, times four, etc. ) ????

I got a kick out of your post, " measures horrible, sounds great ". Designing by listening ( to musical instruments ) and not measuring much is my key approach. Hence, in particular, Q1 above !!!

My audio mentor Dennis Fraker and I both use this m22759/11 wire......... without second guessing .

It is a outright bargain VS all else we know of, on the basis of cost VS performance. Especially when used with our SE DC tube amp designs and ALTEC / GPA speakers. YMMV. ....... Fine !!

If your " stranded copper / silver plated " wire is the m22759/11 type, be sure to route the wires so that the two polarities do not touch each other even ONE time, to maintain best top-end performance. Also avoid either polarity touching metal objects, as it reduces the wire's transfer efficiency audibly !! ( read Pierre Sprey, Wire Management ).

Six answers please. Take your time. Thanks.

Jeff



BTW....I like you trying out NO crossovers on your full range drivers.

Often,........ less is more.

I removed the crossover for my VOTT A7-8's ALTEC 515B woofers over two years ago, and much prefer hearing them running direct off the amp,....... powered full range.

There is a 800 hZ. 12 dB roll off on the 802 compression drivers. Am tempted to remove and hear those 802Ds without crossover parts also !!

Now......... you should be able to easily optimize your two DC SE KT88 amps' various internal AC polarity hook ups. Have fun !!!


From today I have disconnected my sub-woofer from my setup due to failure in my sub-woofer power supply connection. Infact this was a blessing bn disguise. Now i am playing direct from my main OB speakers and don't have to worry about subwoofer phase shifts and room placements.

I added cardboard wings only on the 12" Alnico woofer sides on the rare to extend them from previous 4" to now 18" on both side. This prevents cancellation of front vs rear waves there by giving an additional octave of extension on the lower end. Am I missing my subwoofer? Yes and No. Yes - because I have so much been spoilt by thumping deep bass from my sub-woofer, I have some kind of withdrawal symptoms :)- TBH.

No - because the bass is natural and plays bass if its there in the recordings. Tabla and Dholak sound as if played in the room with accurate balance which was missing when using a sub-woofer no matter - how accurately i levelled them. May be without the sub-woofer the overall coherence in the sound stage has improved and is more accurate. Male voice is more natural and real without any artificial low end.

I have found the same as you, that adding a sub woofer is popular, but generally a degrade in naturalness. They play bass, when it is not in the recording, all the time.

Not in my home's audio system - please. Thank You !

So sorry, but I have previously reacted to Hari's post above. Excuse the duplication !! My error.

Jeff
 
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Gudebrod audio

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After 2 weeks of listening and break-in of the tin plated copper wire more than 40+ hrs of listening, did not like what i heard from this wire. The highs though in balance with the rest of the frequency seem to be laid back and not accurate. Hence i restored back everything to my silver plated copper wire and got back the symmetry. The silver plated copper wire sounds much direct, involving and keeps me engaged in my music and exiting too. Btw, i also made the below changes,

- Changed my speaker positioning from parallel wall to diagonal wall placement
- Changed my 4 year old Russian driver to a brand new Russian driver - same model nbr - but without any abuse

After the above changes i hooked them up and listened to them. Wow, i was amazed at the sound transparency, coherence, dynamics went to another level which was never heard before and i was extremely happy with the overall outcome. This was on a Friday evening and went on to listen music till late night without even realizing that it was 1AM or police will be on my door.

I went ahead just listening to the newly discovered magic next day morning and was super happy with this happening. Came late evening, i though why not try to measure them and discover how they measured. Below is what i measured- posting only the FR curve and Step response (if FMs are interested in anything else let me know)

View attachment 69067

View attachment 69068


it measures HORRIBLE. As you can see there is no bottom-end, no top-end and more of peaky mid-range. Anyone would discard this speaker if they look at only the measurement without listening. This made me wonder there might be something wrong with my measurement gear. The rest of the evening i again only listened to the music and late night around 12 mid-night i carefully checked all my measurement gear to see if there was any mistake in the measurement and measured again. Ditto i again got the same measurement. So nothing was wrong in the measurement. It measured again HORRIBLE. Was something wrong with my EARS? I dont think so as i was hearing my family members and neighbors exactly as yesterday. So my ears are also ok. Nothing wrong with them either.

If both my ears and measuring is accurate then whatever 3% to 4% knowledge i had gathered in the past 10+ years have to be dumped and i will have to start again from zero. What i am measuring and what i am listening does not even closely correlate. Its one of the greatest secrets in audio which i am slowly but surely realizing. I know that ARC fans will troll me and start hating me for this discovery - but again those who follow my post also know that i too am a measurement freak and this discovery has to be made public.

Will try and post a recording of the speakers (if possible) for others to decide later if there is any debate.

Thanks for looking.
Hi Hari,
This interested me so much I built a pair for under $70, I current us a pair of reality cables $475 made by a guy I know locally. Probably the most accurate sounding cables I owned and have stacked them up against many other much more expensive cables. Well, I really don’t know what to say sonically these beat up my cables from my buddy and they’re extremely good! I know they need break in but wow! Very balanced great bandwidth and sonics!!!! Thanks for the write up. If anyone is thinking about this it’s a must have item.
 

Gudebrod audio

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Hi Hari,
This interested me so much I built a pair for under $70, I current us a pair of reality cables $475 made by a guy I know locally. Probably the most accurate sounding cables I owned and have stacked them up against many other much more expensive cables. Well, I really don’t know what to say sonically these beat up my cables from my buddy and they’re extremely good! I know they need break in but wow! Very balanced great bandwidth and sonics!!!! Thanks for the write up. If anyone is thinking about this it’s a must have item just follow the recipe posted above #14.
 

grindstone

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Seems like too-many changes at once to know what did what (at least for me). Maybe verify listening angle (where you sit/like it vs. what angle to chair was at prev speaker location). There may be something complementary in your room/furnishings that lets all the radiation arrive at your listening spot in a more pleasing way (besides different reflections presumably gated-out). You have many radiation sources so even speculation is hard :) Your honest and open inquiry is refreshing and rings true for some of my own experiences. If you do (acoustic) sims, maybe you can gain insights. Preferences are individual--if you are happy with sound, it is all that matters irrespective of what perceptions of experiences are. Maybe next time you set-up the mic, maybe take one with a reduced window (?) just to see. Off-axis 12's are falling-off pretty hard by the time that hump happens--maybe it is flat at your chair.
 

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drlowmu

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5-18-22........................ DIY SPEAKER CABLES............................ ULTRA HIGH PERFORMANCE

The speaker cables that were made for Hari, in 2021, and were recently DIY built by Guderbrod Auidio, are made precisely as follows:

Wire: Military Specified m22759/11. This is multi stranded copper wire, silver plated, in a teflon outer jacket . Best source : APEX Jr. Surplus Electronics in California, USA. Steve is the shop owner - a good person !!

Configuration : Each polarity consists of three leads in parallel, 12 AWG + 12 AWG + 14 AWG. ( equivalent AWG is 8 AWG , thus this configuration provides a superb transfer efficiency. ) Terminate the ends into appropriate high quality spade terminals. Each polarity trio of 12 + 12 + 14, after spade lug termination, is twisted around each other, loosely - not tightly. Perhaps two inches per twist.

Lengths : Specifically cut the Mil Spec wire to two Robert Fulton wire lengths , or 57 1/8th inches times two, which is 114 1/4 inches. Do not cut amplifier-to-speaker leads shorter than two integrals, as this will sound worse.!!! Only if you absolutely require extra long leads, use three Fulton lengths. Cut the wires at 171 3/8ths inches long, all three per polarity equal in length.

114 1/4 inches is also best sounding length as a Power Cable, 12 AWG typically is used, with 20 A. IECs.

Implementation : Be absolutely sure, when in use, that the two twisted polarities do NOT ever touch each other, in their route from the amplifier to the speaker. Not even ONE time !!!! Do not lay wires on rugs, metal objects, or plastic surfaces, as it is a degrade in energy transmission.. It is best to float the two polarities, going from power amp to each speaker , in MID AIR, and not touching each other, or, other surfaces. ( Read Pierre Sprey, " Wire Management ".)

ADDITIONAL use : Once you come to understand what this wire does - musically, use this same Mil Spec wire from the crossover, typically inside your speaker, to the various drivers. Two times 12 AWG works very well to woofers. One times 14 AWG works well to midranges, and compression tweeters. Again, no-touch their polarities !! The best lengths from the crossover to the driver are one Fulton increment, 57 1/8th inches, OR one- half a Fulton increment , 28.56 inches.

This speaker wire configuration was developed by my Audio Mentor, Mr. Dennis Fraker of Livingston, Montana, USA.

Enjoy this.


Jeff

Apex Jr Mil Spec Prices.jpg
 
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Hari Iyer

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The new Russian FR dirver 10gdsh-1-4 now has completed 3 weeks of installation (which is around 50+ hours of my listening time). The initial peakiness has reduced much and i did a measurement again today to check. This is what i got,

1652958819974.jpeg

If the response at post # 13 is compared with the above, then the peak response have drastically reduced (though not flat) with nothing changing other than the driver break-in. Agreed there could be small variation (in cm) where i have positioned my mic but that wont cause a 10dB of peak reducing. So the moral of the story for me is - don't judge anything now and let the driver completed 400+ hrs of break-in and then measure again. Even the Cleveland Alnico 12" woofer must have completed only around 200+ hrs of break-in as they were installed around end of Feb this year. Next measurement post will be around end of July or Aug as that would mean sufficient break-in time to measure again and report.
 

Dr.Gary

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Hi Hari,
This interested me so much I built a pair for under $70, I current us a pair of reality cables $475 made by a guy I know locally. Probably the most accurate sounding cables I owned and have stacked them up against many other much more expensive cables. Well, I really don’t know what to say sonically these beat up my cables from my buddy and they’re extremely good! I know they need break in but wow! Very balanced great bandwidth and sonics!!!! Thanks for the write up. If anyone is thinking about this it’s a must have item.
You state that the pair of cables that you built for under $70 have "great bandwidth". What is the bandwidth that you measured and what was the measurement methodology that you used?.

The cables that I currently use are the Fulton Gold, and the end-end, amplifier-speaker difference in frequency response that I measure under actual in-use (music) conditions is down 0.1dB at 20kHz. I made the measurement using a Brual & Kjaer Type 2035 dual channel signal analyzer whose two input channels are matched in gain to better than 0.1dB.
 
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