Dynaco A-25 Restoration - Measurements - Comments

[Pete B]

These caps were replaced some time ago, but I just used poly caps that I had as spares.

5 uF is not a common value, whereas 4.7, 5.1, and 5.6 are. I used 4.7s previously and

I decided to bring these back to spec using ClarityCaps from Madisound which do come

in a 5 uF value. I also removed the minor mod that I previously did so that these would

be as close to original as possible.

Measured data for the replacement caps, note that they are within 2% of the design

value of 5 uF and the consistency is very good:

First cap measures:

4.93 uF + .20R at 5 kHz

4.92 - 4.93 uF between 1 and 8 kHz ESR = .12 to .20 ohms over the same range.

Second sample measures:

4.92 uF + .19R at 5 kHz

4.91 - 4.92 uF between 1 and 8 kHz ESR = .10 to .20 ohms over the same range.

I used .33 ohm 5W resistors in series to roughly match the ESR of the original electrolytic

cap.

[Pete B]

These are finished, essentially stock. I did use low cost gold binding posts, t-nuts,

thread inserts, and cap head allen screws to hold in the drivers.

Ran an input impedance sweep, here are some points of interest:

Dynaco A-25, Switch = 3 (center) Clarity caps:

Zmax = 13.1 ohms at 68.2 Hz

Zmin = 7.0 at 136 Hz

Zpeak = 23.4 at 1470 Hz

Z10K = 7.8 at 10 kHz

Some people question if two system in parallel are really half the impedance.

This is very basic and the answer is yes if they are the same impedance, here

is a measurement of these two A-25s in parallel, switch = 3, Clarity caps:

Zmax = 6.89 at 68.2 Hz

Zmin = 3.54 at 126 Hz

Zpeak = 11.6 at 1470 Hz

Z10K = 4.0 at 10 kHz

The two systems do not match exactly, they are very close, and the parallel impedance

is quite close to half.

[Pete B]

Finally finished: http://baselaudiolabs.googlepages.com/A25-FRNT-SM.JPG

[emilime75]

Hello all. While searching for info about my A25's I came across this site. I'd like to say hello to everyone and hopefully resurrect this old thread and have some of my questions answered by the knowledgable folks that I've been reading here.

The speakers are being used in my bedroom and are hung on the wall next to a 42" plasma television. Now, while I love how they sound, I don't really care for their appearence next to the tv. So, I'd like to build new boxes for them that are flatter in shape and more modern in appearence and keep them mounted on the wall next to the tv.

I have built a ton of speaker cabinets in the past and I am a wood worker as well, so construction and finishing are not a problem, design, however, is in this case a bit of a mystery to me. While I understand ported and sealed cabinets and their characteristics, I am pretty much clueless about aperiodic vents.

Can a sealed or a traditionally ported cabinet design be built for the original components with success? Has anyone here tried this?

I have measured the original cabinet's dimensions and have come up with an internal volume of .85 ft3. My goal for the shape of the new boxes is to maintain the width of the original cabinets of 10.125 inches measured internally. The depth I would like to have no more that 6.5 inches externally, and using .75 inch material for my boxes would result a 5 inch internal dimension. If I made the height of the box 28.125 inches internally, I would end up with exact same volume as the original while changing the shape to fit along side the TV.

Any thoughts on the subject? Any suggestions? I would appreciate any and all comments anyone here might have. Thanks.

[Pete B]

Hello all. While searching for info about my A25's I came across this site. I'd like to say hello to everyone and hopefully resurrect this old thread and have some of my questions answered by the knowledgable folks that I've been reading here.

The speakers are being used in my bedroom and are hung on the wall next to a 42" plasma television. Now, while I love how they sound, I don't really care for their appearence next to the tv. So, I'd like to build new boxes for them that are flatter in shape and more modern in appearence and keep them mounted on the wall next to the tv.

I have built a ton of speaker cabinets in the past and I am a wood worker as well, so construction and finishing are not a problem, design, however, is in this case a bit of a mystery to me. While I understand ported and sealed cabinets and their characteristics, I am pretty much clueless about aperiodic vents.

Can a sealed or a traditionally ported cabinet design be built for the original components with success? Has anyone here tried this?

I have measured the original cabinet's dimensions and have come up with an internal volume of .85 ft3. My goal for the shape of the new boxes is to maintain the width of the original cabinets of 10.125 inches measured internally. The depth I would like to have no more that 6.5 inches externally, and using .75 inch material for my boxes would result a 5 inch internal dimension. If I made the height of the box 28.125 inches internally, I would end up with exact same volume as the original while changing the shape to fit along side the TV.

Any thoughts on the subject? Any suggestions? I would appreciate any and all comments anyone here might have. Thanks.

The issue with any long dimensions is that there will be a standing wave resonance(s) at lower-mid frequencies in addition to

the fundamental resonance. Lower freq resonances are more difficult to tame with damping material. I do think that

you'll be OK with the 28" dimension, as long as you place the woofer toward the middle, perhaps 6" offset to spread any

resonances. I'd make the port area and damping in the port the same if you like the stock A-25 bass. Predicting internal

resonances is not a simple matter; I suggest building a rough test cabinet first.

[craig]

Hi i have a few questions about restoration. What happens if you had a A25 woofer that was abused to the point woofer was pretty frayed/ ripped but went in for a repair ( van l speakerworks chicago) does this mean the roll over is not as good on it? is a woofer compromised due to repair if other one is in mint condition ? What happens if you replace just the resister on the crossover of an A25 ?

How come dynaco A25s sound slightly different from one another ? I think i have the scan and the seas version, the scan version seems a little deeper on the bass response. but i could be wrong. Last question, can you find modern dynaco A25 woofer replacements? and if so how do they compare to the original sound wise and how much do they cost ? ( i looked but they were out of stock)

[dynaco_dan]

Hi i have a few questions about restoration.

Q... What happens if you had a A25 woofer that was abused to the point woofer was pretty frayed/ ripped but went in for a repair ( van l speakerworks chicago) does this mean the roll over is not as good on it?

A... Look on ebuy or similar for an identical model number used woofer, confirm whether it be a Scan or Seas model, round or horned but verify it is also a 10" version, 8

ohms and not 4 or 15 ohm impedance.

Q... Is a woofer compromised due to repair if other one is in mint condition ?

A... From my own personal experience there is no repairs with this particular woofer nor should you pay to have someone else tinker with it.

A... Your money is better spent on buying a used woofer and not reconing even, usually about $25.00+/- for buying a used woofer.

A... The paper voice coil former gets pretty hot and ends up charring, also the damage is cumulative and non-healing.

Q... What happens if you replace just the resister on the crossover of an A25 ?

A... There is no reason to replace any of the resistors unless they are burnt or out of spec significantly, possibly the capacitor though.

A... Solen makes a fairly nice PP capacitor replacement.

Q.... How come dynaco A25s sound slightly different from one another ?

A... The Scan and Seas are different drivers.

A... There is more of a major difference between an A-25 and a A-25-XL speaker as well.

Q... I think i have the scan and the seas version, the scan version seems a little deeper on the bass response. but i could be wrong.

A... Two different speaker systems, I've never read or personaly done an A - B test to see what sound differences may be audible, there may be

an audible difference across the band.

A... Any chance of a photo of each of your speakers front baffle board without the grille cloths on?

Q.... Last question, can you find modern dynaco A25 woofer replacements?

A... The newly manufactured replacement drivers of today are different sounding, not a good thing.

Q.... If so how do they compare to the original sound wise and how much do they cost ? ( i looked but they were out of stock)

A... Used is your best bet for replacement drivers.

[craig]

Hi i have a few questions about restoration.

Q... What happens if you had a A25 woofer that was abused to the point woofer was pretty frayed/ ripped but went in for a repair ( van l speakerworks chicago) does this mean the roll over is not as good on it?

A... Look on ebuy or similar for an identical model number used woofer, confirm whether it be a Scan or Seas model, round or horned but verify it is also a 10" version, 8

ohms and not 4 or 15 ohm impedance.

Q... Is a woofer compromised due to repair if other one is in mint condition ?

A... From my own personal experience there is no repairs with this particular woofer nor should you pay to have someone else tinker with it.

A... Your money is better spent on buying a used woofer and not reconing even, usually about $25.00+/- for buying a used woofer.

A... The paper voice coil former gets pretty hot and ends up charring, also the damage is cumulative and non-healing.

Q... What happens if you replace just the resister on the crossover of an A25 ?

A... There is no reason to replace any of the resistors unless they are burnt or out of spec significantly, possibly the capacitor though.

A... Solen makes a fairly nice PP capacitor replacement.

Q.... How come dynaco A25s sound slightly different from one another ?

A... The Scan and Seas are different drivers.

A... There is more of a major difference between an A-25 and a A-25-XL speaker as well.

Q... I think i have the scan and the seas version, the scan version seems a little deeper on the bass response. but i could be wrong.

A... Two different speaker systems, I've never read or personaly done an A - B test to see what sound differences may be audible, there may be

an audible difference across the band.

A... Any chance of a photo of each of your speakers front baffle board without the grille cloths on?

Q.... Last question, can you find modern dynaco A25 woofer replacements?

A... The newly manufactured replacement drivers of today are different sounding, not a good thing.

Q.... If so how do they compare to the original sound wise and how much do they cost ? ( i looked but they were out of stock)

A... Used is your best bet for replacement drivers.

Wow! you helped me a great deal thanks for addressing all of my questions, i kinda figured the old ones were better, but that's also kinda a shame from an historic perspective ( 100 years later ). I'm going to upload a bunch of pics, In these pics there is only one matching pair, I have 2 matching pairs and one unmatched pair but i took one lone speaker in for repair ( voice coil problem ), so only one matching pair are shown in the following pics. I got a 20-50 dollar estimate to fix the lone voice coil defect, ill know weds when i got to pick it up. The first pair shown is the pair working with no problems its also the one with the woofer i had repaired due to abuse (laundry basket and someone i was dating hurt) (heh), The black speaker with the red particle board is the left side of the speaker in for voice coil repair. Anyway not to get to confused one pair is working and sounding great. the fourth picture shows the laundry basket damaged woofer that was semi repaired in my mind. they actually sound quite powerful anyway. The 6th picture shows the other matching pair ( except one is in shop for voice coil repair) I also have pics of the fancy looking BW's that these dynaco's just out perform by leaps and bounds, quite amazing the bw's were not cheap and all the dynaco's shown were resale shop finds some with covers still on them I'v run out of room for pics but would love to show more gear as well in another post, i even have more dynaco A25 i can show more in future posts, One pair looks so old the grill is on top instead of bottom but it also appears the paper wore down, unlike the other pairs that seem to have better made woofers. I will share more pics soon thanks for the advice vern wish i knew you in person would love for someone like you to work on my gear. Yes i'm a dynaco A25 nut.

[dynaco_dan]

Hi Craig

I see in the last photo the two pairs of A-25's.

The photo is fuzzy but it appears in the other photos that you have all Seas drivers.

I see metal staples in a different position than I am used to seeing on the vents.

Could you please take new photos and re-post of the vent openings, please.

The mirror image pair, tweeter on the left of center, are less common than right of center.

Never read or heard why they were ever made in that format.

I can understand that you might want and need mirror image pairs for mini-monitors, etc.

This may have been Dynaco's thought, but, you would need to identify the shipping carton, left and right and keep

them matched from the factory, to the dealer, and to the customer, for well under $100.00 each, not worth that much work.

Doubtfull you or anyone else can hear the resistors being replaced and the switch being eliminated.

The capacitor is another story.

Much has been written here and elsewhere about suitable replacement caps and which type, model and brand to use.

Some have raved about reasonable priced caps and others about the super deluxe and expensive caps.

Most younger listeners might appreciate spending $100.00 per cap per $79.00 speaker but Solen may be a better buy.

There is subtle differences and you may not be able to decide which is the best and most reasonable.

Replacing the internal speaker wire will net you no improvement.

Sometimes we can hear the un-hearable when we spend money.

[craig]

Hi Craig

I see in the last photo the two pairs of A-25's.

The photo is fuzzy but it appears in the other photos that you have all Seas drivers.

I see metal staples in a different position than I am used to seeing on the vents.

Could you please take new photos and re-post of the vent openings, please.

The mirror image pair, tweeter on the left of center, are less common than right of center.

Never read or heard why they were ever made in that format.

The pair that have tweeter left of center, what you said about that threw me off a little, is there a difference other then location ? He's not going to replace tweeter thats the good not ripped up pair. They have been fixed you can read about that on my other post, but he offered to redo them for more money, I know he cleaned the connects on the lone one i brought in for repair, maybe i should just go pick it up but im worried the other uncleaned one might not be balanced, maybe im just nuts

I can understand that you might want and need mirror image pairs for mini-monitors, etc.

This may have been Dynaco's thought, but, you would need to identify the shipping carton, left and right and keep

them matched from the factory, to the dealer, and to the customer, for well under $100.00 each, not worth that much work.

Doubtfull you or anyone else can hear the resistors being replaced and the switch being eliminated.

The capacitor is another story.

Much has been written here and elsewhere about suitable replacement caps and which type, model and brand to use.

Some have raved about reasonable priced caps and others about the super deluxe and expensive caps.

Most younger listeners might appreciate spending $100.00 per cap per $79.00 speaker but Solen may be a better buy.

There is subtle differences and you may not be able to decide which is the best and most reasonable.

Replacing the internal speaker wire will net you no improvement.

Sometimes we can hear the un-hearable when we spend money.

[craig]

Hi Craig

I see in the last photo the two pairs of A-25's.

The photo is fuzzy but it appears in the other photos that you have all Seas drivers.

I see metal staples in a different position than I am used to seeing on the vents.

Could you please take new photos and re-post of the vent openings, please.

The mirror image pair, tweeter on the left of center, are less common than right of center.

Never read or heard why they were ever made in that format.

I can understand that you might want and need mirror image pairs for mini-monitors, etc.

This may have been Dynaco's thought, but, you would need to identify the shipping carton, left and right and keep

them matched from the factory, to the dealer, and to the customer, for well under $100.00 each, not worth that much work.

Doubtfull you or anyone else can hear the resistors being replaced and the switch being eliminated.

The capacitor is another story.

Much has been written here and elsewhere about suitable replacement caps and which type, model and brand to use.

Some have raved about reasonable priced caps and others about the super deluxe and expensive caps.

Most younger listeners might appreciate spending $100.00 per cap per $79.00 speaker but Solen may be a better buy.

There is subtle differences and you may not be able to decide which is the best and most reasonable.

Replacing the internal speaker wire will net you no improvement.

Sometimes we can hear the un-hearable when we spend money.

The guy who wants to repair it seems to think bypassing the switch helps a great deal but i forgot the technical terms he used, maybe i should just ask him not to replace the entire thing and just put it on the spot one above normal so the switch is still active ?

[dynaco_dan]

The guy who wants to repair it seems to think bypassing the switch helps a great deal but i forgot the technical terms he used, maybe i should just ask him not to replace the entire thing and just put it on the spot one above normal so the switch is still active ?

Hi there

Typically replacing the cap usually is a highly recommended step, with any brand of speaker and can at times, provide a slightly audible improvement.

If there is no output from just the tweeter, this would be suspect.

Bypassing the switch has not been a recorded step as yet, and unless it's broken, best leave it alone.

It certainly have not been a problem historically.

Think about how many times we adjust the tweeter level controls in our lifetime, not many for most everyone.

Most listeners probably set it and forget it.

Can you imagine someone getting up from their chair and adjusting the tweeter level for each cut of each and every cd.

It is a simple switch with no dead spots and each setting is more precisely repeatable, unlike a pot or L-pad.

Obviously if one of the resistors is burnt it will need to be replaced, extremely rare though with Dynaco, I've not heard of one, yet.

Dynaco A-25 speakers are about as close to being trouble free as is possible, barring burning out the woofer, their main weakness.

A recommended 1 amp or smaller fast blow glass fuse, in a open style fuseholder, will help lessen this event happening.

A reasonably compact, well veneered, fairly neutral sounding speaker with some limitations at a very attractive retail price when new.

They were voted quite often as a best buy speaker.

I have enjoyed several of their models with all their warts.

Remember, spending money will bring you most often, little or no improvement but we all justify it.

updated 20110714 10:02 AM

[Pete B]

Is there anyway to restore the correct order of these posts? Moderators?

Perhaps you could allow us to edit our own threads, just a one time thing.

[didyman]

Hello guys, hello Pete!
I have a pair of these, marketed as A40XL, but..it has H087 tweeter. Everything is mixed up in this enclosure-i seek for help to understand and pair the right speakers. I have a stock.

-"Original" setup of mine is a H87, with 4 Ohm impedance

-X-Over has 8 uF cap (wich may be well matched with 4 ohm tweeter)

-Woofer is 25F-EW with 8 Ohm impedance (altought the label has 4 Ohm printed on it and seems no repair of any kind visible on the units)

-Claimed impedance is 8 Ohm, but no sticker, or anything else.

My simple question: Originally, how much is the impedance of the drivers and the box (may a 8 and 4 ohm was present?) and what was this box originally-an A35, or A40XL?

And second-i have a 4 Ohm 25TV-EW and a pair of 8 Ohm H087. I can use anything, but wich ones to rebuild original? I assume, the TV-EW would be a bit better option, but how the A40XL is tailored for the 25F-EW, did it have something diffence inside?

[didyman]

OK, i got my answers, partially. The box is an A35, 8 Ohm, the capacitor is the standard value for A35's lower x-freq. The tweeter is original, and measures over 5 Ohm, just the 4-8 Ohm sticker isn't as visible as on the other. Just tried the alnico instead of ceramic in one  of the cabinets. Much better, much more linear. The rest is still open (sorry for asking in an A25 topic

[TheFrugalAudiophile]

Hello, Pete, I just joined the forum. I learn a great deal here and I'm not handy like you so I don't build but we have replaced tweeters in our Dynacos with one inch units by ScanSpeak and Vivfa.

I see you like both the Dynaco A25 and EPI 100 classic loudspeakers; the EPI was always "brighter" to me and I hated the high pressure sales when I was younger and it was introduced; they had a wall with a switcher and made sure it sounded "better" than Dynacos, AR 2aX, Advents, etc. Tested at home, and with older electronics I didn't hear details like a harpsichord continuo in Bach, dispersion wasn't as good of highs to me as the A25, but much better sounding than most 21st century units.

There are successor speakers out there, the SEAS A26 and the Human Speaker.

Here are links:

https://www.madisoundspeakerstore.com/2-way-speaker-kits/seas-a26-10-2-way-kit-pair-based-on-the-classic-a25/

https://www.humanspeakers.com/human/81.htm

Will you be discussing on this site or are you mostly interested in restorations? Glad to see you're still active here on this forum and a longtime member!

I've a blog here and I'm displeased with the much hyped B6 Elac (no offense if anyone hear likes it):

https://thefrugalaudiophile.blogspot.com/

Thanks and best wishes,

T.F.A.

[Pete B]

@TheFrugalAudiophile   I've been building and designing speakers since I was a kid and I like to study the

classics to see if there are any "tricks" or design methods that are not mentioned in the literature.  That is

my main reason for studying many of the vintage designs.  My brother and I as teens read the stereo mags

and we debated with my dad about Dyna A-25 s,  Large Advents,  and we also heard KLH 6 s at the store.

We ended up with Advents because the store didn't have A-25 s and they seemed like the best deal.

I was given a pair of A-25 s in college in need of repair so I know them fairly well but I bought this pair

in order to measure an "Aperiodic" design which I have not yet done other than to read the literature on it.

My current view is that they wanted to "cram" that 10" woofer into the smallest box possible which if 

sealed would have led to a high Fc and High Qtc.   The lossy leak lowers the Q but does not really help

bass response.  It is a non-optimal design IMO.  What the A-25 really wants is a much larger box 2 -3 cu ft

tuned to 35 Hz with a moderate amount of internal damping.  It also needs a modern tweeter.

The DeVore Orangutan supports this theory - note that they are tuned to 43 Hz for strong bass for 

Low E on a bass guitar in the still too small box:

https://www.stereophile.com/content/devore-fidelity-orangutan-o96-loudspeaker

 

The A-25 is a very old design and it shows, as are many vintage speakers, both the woofer and tweeter

have paper voice coil formers providing very limited thermal capacity.  The OLA in contrast has a strong

bronze former that will take massive power.  Tweeters usually have paper thin aluminum VC formers.

The A-25XL has a newer version of the woofer with an aluminum former and a stronger ceramic magnet,

many say that they do not sound as good probably because the stronger magnet removes some of the

built in baffle step and some contouring of the woofer's response is needed to compensate.

The A-25 has a 1.5" tweeter that has very limited output above 12 KHz.  A-25s sound reasonably well

balanced even though there is no crossover on the woofer probably as a result of the high VC inducance

acting to shape the response.   I've never bothered to measure the A-25 frequency response or seen one

published, but they sound so good that I've always been suspicious of a depression, perhaps large,

around 2 KHz.  Sure enough, I found a magazine published response and it was there.  It also showed 

the steep roll-off in the bass around 75 Hz.  I started a thread here with some history and links to the 

articles on the A-25, one with frequency response curves:

http://www.classicspeakerpages.net/IP.Board/index.php?/topic/11431-some-history-on-dynaco-founded-by-david-hafler-and-ed-laurent-in-1955/

There are 10 dB dips in the frequency response on axis but they go away slightly off axis, so if you 

position your speakers right it is possible to get a much smoother response.

 

Even with all the negatives about Dyna A-25 s you can get a really nice balanced sound due to them

having a tweeter level control and in the right position a smooth midrange.  Leaving a bit of the

midrange notch can make them "magical" because it seems to match well with what is needed from

2 speakers producing stereo in a home listening room.  Just do not expect to Rock out at party levels

for hours on end.  Use them with a 50 to 100W max amp being very careful on the level and use the 

power just for peaks.

 

I once started a thread on the Stereophile Forum "When Bad is Good" to discuss how sometimes

theoretically correct is not "best" in a home listening space.

 

[TheFrugalAudiophile]

On 2/2/2020 at 12:49 PM, Pete B said:

@TheFrugalAudiophile   I've been building and designing speakers since I was a kid and I like to study the

classics to see if there are any "tricks" or design methods that are not mentioned in the literature.  That is

my main reason for studying many of the vintage designs.  My brother and I as teens read the stereo mags

and we debated with my dad about Dyna A-25 s,  Large Advents,  and we also heard KLH 6 s at the store.

We ended up with Advents because the store didn't have A-25 s and they seemed like the best deal.

I was given a pair of A-25 s in college in need of repair so I know them fairly well but I bought this pair

in order to measure an "Aperiodic" design which I have not yet done other than to read the literature on it.

My current view is that they wanted to "cram" that 10" woofer into the smallest box possible which if 

sealed would have led to a high Fc and High Qtc.   The lossy leak lowers the Q but does not really help

bass response.  It is a non-optimal design IMO.  What the A-25 really wants is a much larger box 2 -3 cu ft

tuned to 35 Hz with a moderate amount of internal damping.  It also needs a modern tweeter.

 

The DeVore Orangutan supports this theory - note that they are tuned to 43 Hz for strong bass for 

Low E on a bass guitar in the still too small box:

 

https://www.stereophile.com/content/devore-fidelity-orangutan-o96-loudspeaker

 

The A-25 is a very old design and it shows, as are many vintage speakers, both the woofer and tweeter

have paper voice coil formers providing very limited thermal capacity.  The OLA in contrast has a strong

bronze former that will take massive power.  Tweeters usually have paper thin aluminum VC formers.

The A-25XL has a newer version of the woofer with an aluminum former and a stronger ceramic magnet,

many say that they do not sound as good probably because the stronger magnet removes some of the

built in baffle step and some contouring of the woofer's response is needed to compensate.

The A-25 has a 1.5" tweeter that has very limited output above 12 KHz.  A-25s sound reasonably well

balanced even though there is no crossover on the woofer probably as a result of the high VC inducance

acting to shape the response.   I've never bothered to measure the A-25 frequency response or seen one

published, but they sound so good that I've always been suspicious of a depression, perhaps large,

around 2 KHz.  Sure enough, I found a magazine published response and it was there.  It also showed 

the steep roll-off in the bass around 75 Hz.  I started a thread here with some history and links to the 

articles on the A-25, one with frequency response curves:

http://www.classicspeakerpages.net/IP.Board/index.php?/topic/11431-some-history-on-dynaco-founded-by-david-hafler-and-ed-laurent-in-1955/

There are 10 dB dips in the frequency response on axis but they go away slightly off axis, so if you 

position your speakers right it is possible to get a much smoother response.

 

Even with all the negatives about Dyna A-25 s you can get a really nice balanced sound due to them

having a tweeter level control and in the right position a smooth midrange.  Leaving a bit of the

midrange notch can make them "magical" because it seems to match well with what is needed from

2 speakers producing stereo in a home listening room.  Just do not expect to Rock out at party levels

for hours on end.  Use them with a 50 to 100W max amp being very careful on the level and use the 

power just for peaks.

 

I once started a thread on the Stereophile Forum "When Bad is Good" to discuss how sometimes

theoretically correct is not "best" in a home listening space.

 

Hello, Pete,

Thanks for your thoughtful reply.  I don't have your technical expertise and don't disagree with your assessments. I'd be curious as to your take on the more current speakers, if you have heard them. Theoretically, the Elac B6 etc. that I didn't like measures better than the Dynaco for highs, etc. but I found their "musicality" far inferior. Andrew Jones (maybe my room,  maybe not) seems to favor a sound that clearly appears "hollow", even his Pioneer Atmos has it.

Of all things, I think the Dayton (after I returned the Elacs to Amazon) does a much more musical, realistic job on voices than the Elac; I use as the height speakers. Do you get to listen to new units? The nice thing about inexpensive speakers the cost of a reasonable dinner is that one can have fun.

https://www.parts-express.com/dayton-audio-mk402x-4-2-way-bookshelf-speaker-pair--300-465

The high pressure sales of Fred Locke Stereo (I note someone here bought an AR 2AX though they were "pushing" another product) was a turn off; online sales is pretty nice, great support from Emotiva so far. My point about Locke is they pushed the "Heil" what was it ESS and it sounded bright and terrible to me. Have you experienced the "Heil" or AMT Tweeter and do you have thoughts? They pushed EPI but comparing that to the A25 it could be equalized to sound as bright, but again, more detail in music. They plugged an A25 into an Equalized Electrovoice unit, said it was the EPI and when I pointed out it was a Dyna they all but threw me out of the store (this was decades ago, most East Coast dealers were sadly Audio Ferengi) and so what, RIA is equalized; there's a lot of B.S. in high end, hype, etc. Again, Dyna A10s with SEAS 1.5 do so much better on vocals than the hyped Elacs; Steve the "Audiophillia" Guttenberg is eccentric but his test CD is great. But he loves the Elacs. 

https://www.amazon.com/Ultimate-Demonstration-Disc-Critical-Listening/dp/B019GRAD0E

I don't know if your analysis agrees with Holt's take that I cited in my blog, he's less critical than you; I was able to obtain useful bass though not high subwoofer quality strength down to 30HZ. They just do a wonderful job on voice.

https://thefrugalaudiophile.blogspot.com/2020/01/the-dynaco-a25-my-first-high-quality.html

Here's a link to the A26; pricey for me:

http://www.seas.no/index.php?option=com_content&view=article&id=475:seas-a26-kit&catid=66:seas-diy-kits&Itemid=365

https://www.madisoundspeakerstore.com/2-way-speaker-kits/seas-a26-10-2-way-kit-pair-based-on-the-classic-a25/

 

My A25s don't take much EQ per my Emotiva UMC-200 analysis; the quality of the recording matters. I wonder if there can be measurable "resolution" beyond frequency response, i.e. the amount of data produced; there was far more detail and vocal information in the A25 and even the Panda bear Chinese Dayton than the Elacs. I think the price now is too expensive unless you buy and return back to Amazon. I hadn't planned to return but I'm a voice in the wilderness with my opinions.  I wrote about the A26, perhaps those are worthy of consideration in 2020. And the Emotiva did in fact see your dip and make a small adjustment but I use my own curve; some of Emo-Q's settings were just crazy. 

I agree about the XLs, they are the rear speakers in my set up but their original tweeters that rang and blew up were replaced with Vifas that were made not as now in China but in somewhere in the Norse countries, like ScanSpeak. Sound like the A25s but a little better dispersion, really not a great difference with movies, music, etc.

Electronics now are much better. I had nothing but problems with Sony and later Carver units; the Emotivas are great for the money. A guy who fixes even multi-thousand units is skeptical of all the hype. I wonder your thoughts here (the Frugal Audiophile who turns up on search engines; you can't find me) about Mr. Rappaport's thoughts, if you have time? He praises Hafler, and I agree. I wish I used the Dyna Stereo 70 amps instead of my problematic Sony integrated. Moved on to Carver, "flat" sound, not much detail. Over forty years later, the A25s are really shining.

https://www.essenceelectrostatic.com/the-frugal-audiophile/

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The packaging of the products continues to grow in cost, the amplifier chassis’ (the most expensive part on all Class A/AB amps) grew huge in size to hold enough heat sink to dissipate the heat because audiophiles hate fan noise. Speaker cabinets grew larger, requiring expensive damping and resonance control to keep them from coloring the sound. The cost of labor and materials to make an inert speaker cabinet accounts for 80% of the total budget to build the biggest speakers.  The real question comes down to this; can you actually hear the difference between a $50K system and a $3K system and if so, is it worth the difference?  IMHO no, you cant.  In fact, the listening room acoustics plays such a huge role in what we hear that throwing more money at the speaker system is foolish, a good system in a bad room will still sound bad.  A decent system in a great room will always sound great, especially if you play the latest and best hi res audio content.

Thanks, Pete and keep up the great work. Let me know your thoughts on modern speakers. By the way SEAS fabricated some of ELAC's pricey "Vela" AMT Jet tweeter (cabinets, drivers were made in Germany).

 

Edited February 17, 2020 by TheFrugalAudiophile
vocals of Elac, spelling error, clarification, Veela, delete Human

[TheFrugalAudiophile]

Pete, I think we're coming at this from two different perspectives. You're speaking with an engineering background and I'm just a listener. The Emotiva 7.1 processor did in fact in its EMO-EQ process make some adjustments in the areas (the drop at 1 KHZ, the crossover point) but I prefer manual EQ with less aggressive treble than the Emotiva's evaluation. There is more to human listening than adjusting to artificial, digital test tones.

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The A-25 has a 1.5" tweeter that has very limited output above 12 KHz.  A-25s sound reasonably well

balanced even though there is no crossover on the woofer probably as a result of the high VC inducance

acting to shape the response.   I've never bothered to measure the A-25 frequency response or seen one

published, but they sound so good that I've always been suspicious of a depression, perhaps large,

around 2 KHz.  Sure enough, I found a magazine published response and it was there.  It also showed 

the steep roll-off in the bass around 75 Hz.  I started a thread here with some history and links to the 

articles on the A-25, one with frequency response curves:

http://www.classicspeakerpages.net/IP.Board/index.php?/topic/11431-some-history-on-dynaco-founded-by-david-hafler-and-ed-laurent-in-1955/

There are 10 dB dips in the frequency response on axis but they go away slightly off axis, so if you 

position your speakers right it is possible to get a much smoother response.

I found this article accidentally by J. Gordon Holt. Has anyone here ever heard of the speaker he mentions? The Fulton Musical Industries J speakers?

https://www.stereophile.com/content/whos-right-acccuracy-or-musicality

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Stereophile for example feels that, at a time in audio history when superb bass and treble and excellent detail are obtainable from many loudspeakers, the most important remaining consideration is freedom from coloration through the middle range (where, after all, the vast majority of musical activity takes place). We have continued to use and to recommend Fulton Musical Industries J speakers because, despite frequent modifications and manifest weaknesses (ie, low-end and and midrange detail easily bettered by some other systems), they offered what we feel to he the best set of performance compromises of any available speaker system. The FMI Js, in other words, while not quite the equal of some others in some respects, are so markedly superior in their reproduction of real musical timbres that they must be considered one of the most accurate reproducers of music around today.

In this respect I agree with him: I tend to like reproduced sound that to me is more "natural" and while I've never heard the Fulton with its huge cone tweeters to agree they're "better" than the A25s, since Holt recorded live music, is well respected, etc. his remarks are worth considering, but just as with the ELACs, I might not like how they sound in the acoustics of my room (were I to ever hear them and not doing this for a living it's unlikely I ever will) all the same.

In his review at this link, he compares them to the A25 and states why he thinks they're better. He publishes a frequency response curve of both speakers. There is the A25 dip you talk about and an elevation. I don't find my A25s bright; again, the Elac B6 2.0 (whatever) on paper had better stats than the A25, but far less "air", detail, transparency and musical realism to me. Has anyone here heard the modern speakers? Interestingly, SEAS fabricated I think cabinets for the ELAC Vela speaker that use a "Heil" or AMT tweeter, while the tweeters are made in Germany.

Here's the article: https://www.stereophile.com/standloudspeakers/0973fulton/index.html

An excerpt:

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Fulton Musical Industries Model 80 & "J-Modular" loudspeakers

Against the Dyna A-25

In view of the fact that we made that same statement about the Dyna A-25 speakers some time ago (in the issue dated "Summer 1968"), it is enlightening to compare them. They are not similar in sound, and in fact, do not even do best with the same kind of amplifiers. The FMIs were designed to be used with tube amps and they sound at their best when so used. The Dynas seem to do best with solid-state amps, so we made our comparisons with one of the best-sounding amplifiers of each variety that we had on hand: an Audio Research Dual 75 for the Fultons and a Citation 12 for the Dynas (footnote 1).

On direct comparisons, the differences between the speakers were immediately obvious. Overall balance was remarkably similar, but there the similarity ended The Dynas went somewhat lower, but did not seem to go out as far at the top. The Dynas sounded subtly zizzy at the high end, while the Fultons sounded smooth. The Dynas sounded somewhat rich, while the Fultons were raw when the music or the recording was that way. But the most noticeable difference was that, while the Dynas sounded very good, the Fultons sounded real. Our subjective response curves (fig.1) show how both systems sounded to us.

The 80s are not entirely without coloration, though. There is a very mild bump in the response at 300Hz, which adds a trace of drumminess to the sound when the speakers are off the floor, and causes a moderately heavy mid-bottom from some recordings when the speakers are on the floor near a wall. There is also what sounds like a broad response rise centered at around 1.5kHz from a lot of commercial recordings, but the fact that it was absent from others, as well as from tapes we made ourselves, suggested that the speaker was merely reproducing what was on the recordings themselves.

Stereo imaging from the 80s is good but only moderately so. Center-image specificity is rather vague, and the sound tends to hop from side to side as you move across the listening area. Imaging as well as specificity are best with the speaker axes parallel rather than converging, although parallel aiming tends to reduce the effective listening area. Best results, with optimum imaging, specificity, and listening area spread, are with the speakers slightly above or below ear height. This also produces the largest apparent source size, giving the impression of two truly vast systems, with some sounds seeming to emanate from beyond the "stage" width of the speakers.

At any rate, if anyone is interested or alive out there, please share your thoughts, especially if you've heard the Fultons. For what its worth, yes, I use subwoofers, a VMPS Smaller subwoofer with its Dayton Audio original driver replaced by a ScanSpeak 12 inch unit and Sunfire Subwoofers; so I do know what a strong 30 HZ tone sounds like but I have heard (it could be because they are on a bookshelf near a brick wall) credible lower bass from the A25s years ago using a recording of Zarathustra that was known to go (on the LP) to 30Hz; it was audible not really distorted, nothing like the Sunfire. I've heard real (small) pipe organs that are weaker than the better recordings bass output!

Oh, and I posted today on a new Dolby recording technology on my blog. Please comment below or on my blog if you have thoughts.

https://thefrugalaudiophile.blogspot.com/2020/02/will-dolby-atmos-music-revolutionize.html