This entry was posted by Winslow on July 28, 2009 at 2:49 pm under Uncategorized.
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My middle child left for college last Friday, our jazz pianist and accordian player. As Sara and I prepare for life without musicians we realized we have no speakers. Lo and behold, Laura sends us an email noting your latest product.
Given that since age 16 I have listened to nothing but your speakers, I had to order a pair.
Your comments at this web site concerning minimum phase have been very englightening.
Many years ago I read an article by Brian Cheney, the designer and company owner of VMPS speakers, about minimum phase. I still have that article in a file cabinet. He discussed this purely from a crossover design standpoint. At that time, and perhaps still, he touted his use of quasi-second order series crossovers because of their “minimum phase” attributes. He said in the article that only odd order filters, quasi-second order filters, and the filler driver design, as done in some B & O designs, were the only minimum phase designs. After reading your brief but informative articles on the subject, I realized that Brian was speaking of one of many aspects of speaker design that affect phase, even though he presented it as a make or break aspect of a good speaker design. Irving Fried was another one who espoused first order series crossovers as the only option for good speaker design. Not having a design lab or measuring equipment, I have relied on the only design tools I really have: My experience and my ears. Every time I followed advice such as this my speaker designs failed, even though I tried to mimic these with the same European drivers and same types and values of crossover components. My ears are particularly sensitive to the midrange and I could always detect problems in the midrange. As such, in the end, my crossovers were really developed rather than calculated. And, because this is so time-consuming, I’ve decided to trust designers who have produced good speakers in the past, over “rolling my own.”
I said all that to ask this: Is the type or order of crossover design all that significant in the grand scheme of loudspeaker design?
My understanding of the concept “minimum phase” does not make me an authority. The idea I have is that in input directly causes the output, not, for example, like the way train cars jerk, one after another, long after the locomotive has changed speed or like the way resonances in the cone material continue to produce sound long after the voice coil has gone on to another frequency.
In my inexpert opinion, phase distortion is another phenomenon and in itself does not belie minimum phase. Phase has to do with time delay between the input and output. What I mean by phase distortion is when the delay varies with frequency. Some designers try to minimize this phase distortion by particular types of crossovers. I doubt it can be eliminated in any combination of drivers. My own experience is that it is not audible unless abrupt.
Two-way speakers usually crossover in the midrange frequency region. Errors in reproduction are far more likely to come from the drivers than from the crossover. When one has perfect drivers, then crossover performance could become a limitation.
For practical reasons I have always preferred steep crossover slopes so that there is minimal interference between the drivers.
I have just come across an Epicure M1 power amp and Epicure M4 pre-amp here in Sydney Australia and have been asked to put it to market. Both seem to be working very well (great sound!) What’s available with respect to manuals, product specs and pricing? I suspect the buyer will want such things especially considering the vintage (1973).
dear sir;
not a comment but a question..is it possible to aquire parts to repair two older Burhoe speakers..? purchased in the late 70′s..no model numbers only 7435 on the back next to a switch..the fabric surrounding the large(base)speakers has deteriated ..we always felt these were the best we ever heard..thanks in advance,
The models were named for colors. The “Blue” had a blue terminal label and a blue dustcap, a ten inch woofer and two tweeters. humanspeakers.com does reconing. Parts Express has a ten inch woofer with a low f(s).
I appreciate the opportunity to be able to purchase a pair of speakers designed by you. I’ve reviewed the website and just have a few questions.
1. Would the Silent Speaker II be suitable for a small (11′ x 11′) room?
2. If so, would a 50 watt per channel amplifier be enough to drive the speakers to moderate levels, definitely less than 90 dB?
3. Are they made in the USA?
We had an AK meet at my shop last Saturday and one attendee suggested you might have payed us a visit. Rather than answer him with “I dunno”, I figured I would ask you.
In a small room, you might have an issue with the bass. This might be an occasion to turn down the bass control. On the other hand it has never bothered me.
50 watts would be more than enough in the circumstances you describe.
I or a relative assemble the parts, some of which are made in the USA. The tweeters were made in India and the crossovers in Canada. I have used woofers made in Canada, New Hampshire and China.
Mr. Burhoe, as a proud owner of EPI 350′s, 602′s, 201′s, 250′s and M50′s I’m very pleased that you are still in business and offering your designs to the public at good prices. I also have a taste for Shahinian designs as well, but that’s for another day.
With your new speakers, is the cabinet covered in a wood veneer or a wood vinyl?
Thanks for all of your contributions to the audio industry.
thank you for for your comments on the original epi design and it flaws. are you now able to produce an updated crossover that would improve the midrange of the epi 202 model? that is the model with drivers on two sides of the cabinet. if so what would be the cost. thank you in advance, n. l.
Good day Mr. Burhoe. I recently picked up a pair of Reds, and I must say they are excellent. I am very impressed with the sound quality. It appears though, that they have different tweeters; one BA-T1.1 and one WB-T1.1, so I am wondering what the difference is. They look the same, but I am sure there must be something. Which one is original in the Reds. Thanks for your consideration, Mike.
Greetings. I’m not sure whether you’re the type of person who’s willing to revisit
the past, but I’d like to ask about the Energy 22. I notice it’s the only one of
your historical accomplishments that gets a write-up, rather than just a listing,
on the site. Do you look back on the 22 favourably? Do you ever have a chance to
listen to them again, and if so, how do you think they stand up after close to three
decades — still satisfying, or exhibiting shortcomings that modern designs easily
surpass, or …? Disclosure: I have enjoyed my 22s for about 25 years now,
and still do. (Not looking for “validation”, just your impression of the 22
in retrospect.) Thanks. Robyn.
In my opinion, the Energy 22 is one of the greatest alltime speakers. The tweeter without peer. Two areas of improvement, the bass port and the boxy cabinet were addressed to some extent in the Connoisseur.
Greetings, Dave Weiser of Kurzweil spoke glowingly of your speakers on the Keyboard Mag forum (of which I’m a member) so I viewed your product with detail. Besides being a jazz pianist, I am a recovering audiophile. Used to run vinyl through Magnepan 3.5Rs. Loved the enormous width and physical weight of the Maggies (especially on acoustic music), not so excited at low volumes or on painfully bright mixes like classic rock. And they sure required a healthy high-current amplifier to get to “speaking” volume. Still have my VPI turntable, but got rid of the Maggies and Plinius amp and thus am looking for quality speakers. The only quality speakers I owned prior to the Maggies were small Von Schweikert two-way monitors (I still own them), which are wonderful near-fields but obviously cannot resolve the lower octaves like a 6 foot high planar.
I provide that context to ask these questions:
1) As you know, the audiophile marketplace is replete with transducers claiming complete transparency, breathtaking soundstage, etc. Yet every speaker I’ve heard so far has wonderful strengths and some admitted weaknesses. Knowing my historical preferences, can you comment on what my experience with your speakers might be?
2) How efficient are your speakers? Do they require a recommended minimum “floor” of power rating to “speak”?
3) Some bass-downfiring speakers I’ve heard in the past seemed to present a “disconnect” between, for example, the speaking length of the low string on an upright double bass and female vocals (for instance, in a jazz vocalist with trio recording). Can you comment on how your speakers avoid this phenomena…or perhaps I just imagined all that in my head?
Thanks so much, Winslow. I’ll check in eagerly for your reply.
My preference is that speakers have wide dispersion at all frequencies. The Magnepans do not. Listeners who listen mostly for stereo imaging generally speakers which are more directional.
87 dB; 30-200 watts per channel.
The deep bass emanates from a forward facing vent at the bottom of the speaker. The frequencies are so low that there is no possibility of detecting where the source is.
Peter says:
What are the advantages of the new tweeter?
July 28, 2009, 3:02 pmRussell Maier says:
Uncle Win,
My middle child left for college last Friday, our jazz pianist and accordian player. As Sara and I prepare for life without musicians we realized we have no speakers. Lo and behold, Laura sends us an email noting your latest product.
Given that since age 16 I have listened to nothing but your speakers, I had to order a pair.
Hope that all is well with you.
Russell
August 31, 2009, 1:08 amDavid Warren says:
Your comments at this web site concerning minimum phase have been very englightening.
Many years ago I read an article by Brian Cheney, the designer and company owner of VMPS speakers, about minimum phase. I still have that article in a file cabinet. He discussed this purely from a crossover design standpoint. At that time, and perhaps still, he touted his use of quasi-second order series crossovers because of their “minimum phase” attributes. He said in the article that only odd order filters, quasi-second order filters, and the filler driver design, as done in some B & O designs, were the only minimum phase designs. After reading your brief but informative articles on the subject, I realized that Brian was speaking of one of many aspects of speaker design that affect phase, even though he presented it as a make or break aspect of a good speaker design. Irving Fried was another one who espoused first order series crossovers as the only option for good speaker design. Not having a design lab or measuring equipment, I have relied on the only design tools I really have: My experience and my ears. Every time I followed advice such as this my speaker designs failed, even though I tried to mimic these with the same European drivers and same types and values of crossover components. My ears are particularly sensitive to the midrange and I could always detect problems in the midrange. As such, in the end, my crossovers were really developed rather than calculated. And, because this is so time-consuming, I’ve decided to trust designers who have produced good speakers in the past, over “rolling my own.”
I said all that to ask this: Is the type or order of crossover design all that significant in the grand scheme of loudspeaker design?
September 24, 2009, 4:02 pmWinslow says:
My understanding of the concept “minimum phase” does not make me an authority. The idea I have is that in input directly causes the output, not, for example, like the way train cars jerk, one after another, long after the locomotive has changed speed or like the way resonances in the cone material continue to produce sound long after the voice coil has gone on to another frequency.
In my inexpert opinion, phase distortion is another phenomenon and in itself does not belie minimum phase. Phase has to do with time delay between the input and output. What I mean by phase distortion is when the delay varies with frequency. Some designers try to minimize this phase distortion by particular types of crossovers. I doubt it can be eliminated in any combination of drivers. My own experience is that it is not audible unless abrupt.
Two-way speakers usually crossover in the midrange frequency region. Errors in reproduction are far more likely to come from the drivers than from the crossover. When one has perfect drivers, then crossover performance could become a limitation.
For practical reasons I have always preferred steep crossover slopes so that there is minimal interference between the drivers.
September 25, 2009, 10:27 amMarc Charette says:
Dear Winslow,
I have just come across an Epicure M1 power amp and Epicure M4 pre-amp here in Sydney Australia and have been asked to put it to market. Both seem to be working very well (great sound!) What’s available with respect to manuals, product specs and pricing? I suspect the buyer will want such things especially considering the vintage (1973).
Many thanks in advance,
MC
December 14, 2009, 4:28 amWinslow says:
I envy you your find. I have no such information. My only suggestion is to try EpicureM1@yahoogroups.com
December 14, 2009, 8:16 pmdon pilgrim says:
dear sir;
not a comment but a question..is it possible to aquire parts to repair two older Burhoe speakers..? purchased in the late 70′s..no model numbers only 7435 on the back next to a switch..the fabric surrounding the large(base)speakers has deteriated ..we always felt these were the best we ever heard..thanks in advance,
pilgrim,oregon
December 28, 2009, 6:45 pmWinslow says:
The models were named for colors. The “Blue” had a blue terminal label and a blue dustcap, a ten inch woofer and two tweeters. humanspeakers.com does reconing. Parts Express has a ten inch woofer with a low f(s).
January 15, 2010, 7:02 pmGene says:
I have a pair of your Burhoe Blue speakers and need the replace the woofers. What would you recommend as replacement woofer.
Thanks
January 25, 2010, 3:20 pmgene
Rick Hemann says:
Dear Mr. Winslow,
I appreciate the opportunity to be able to purchase a pair of speakers designed by you. I’ve reviewed the website and just have a few questions.
1. Would the Silent Speaker II be suitable for a small (11′ x 11′) room?
2. If so, would a 50 watt per channel amplifier be enough to drive the speakers to moderate levels, definitely less than 90 dB?
3. Are they made in the USA?
Thanks for your help,
Rick Hemann
February 2, 2010, 5:57 pmFrank Carpenter says:
Mr. Burhoe,
We had an AK meet at my shop last Saturday and one attendee suggested you might have payed us a visit. Rather than answer him with “I dunno”, I figured I would ask you.
Regards, Frank Carpenter, Clinton Ma.
February 2, 2010, 8:01 pmWinslow says:
In a small room, you might have an issue with the bass. This might be an occasion to turn down the bass control. On the other hand it has never bothered me.
50 watts would be more than enough in the circumstances you describe.
I or a relative assemble the parts, some of which are made in the USA. The tweeters were made in India and the crossovers in Canada. I have used woofers made in Canada, New Hampshire and China.
February 2, 2010, 9:13 pmWinslow says:
I don’t know what an AK meet is and I don’t recall having been to Clinton. I have been to more places than I can remember, however.
February 2, 2010, 9:19 pmDave F says:
Mr. Burhoe, as a proud owner of EPI 350′s, 602′s, 201′s, 250′s and M50′s I’m very pleased that you are still in business and offering your designs to the public at good prices. I also have a taste for Shahinian designs as well, but that’s for another day.
With your new speakers, is the cabinet covered in a wood veneer or a wood vinyl?
Thanks for all of your contributions to the audio industry.
February 4, 2010, 2:55 pmWinslow says:
The veneer is black ash with a lacquer finish.
February 4, 2010, 7:07 pmnorm says:
thank you for for your comments on the original epi design and it flaws. are you now able to produce an updated crossover that would improve the midrange of the epi 202 model? that is the model with drivers on two sides of the cabinet. if so what would be the cost. thank you in advance, n. l.
February 4, 2010, 7:42 pmMike G says:
Good day Mr. Burhoe. I recently picked up a pair of Reds, and I must say they are excellent. I am very impressed with the sound quality. It appears though, that they have different tweeters; one BA-T1.1 and one WB-T1.1, so I am wondering what the difference is. They look the same, but I am sure there must be something. Which one is original in the Reds. Thanks for your consideration, Mike.
March 28, 2010, 7:35 pmWinslow says:
The Reds were manufactured in Canada by my friends at Audio Products. I am not sure if one was made in New England and one in Toronto.
April 12, 2010, 5:24 pmRobyn says:
Greetings. I’m not sure whether you’re the type of person who’s willing to revisit
April 14, 2010, 6:30 pmthe past, but I’d like to ask about the Energy 22. I notice it’s the only one of
your historical accomplishments that gets a write-up, rather than just a listing,
on the site. Do you look back on the 22 favourably? Do you ever have a chance to
listen to them again, and if so, how do you think they stand up after close to three
decades — still satisfying, or exhibiting shortcomings that modern designs easily
surpass, or …? Disclosure: I have enjoyed my 22s for about 25 years now,
and still do. (Not looking for “validation”, just your impression of the 22
in retrospect.) Thanks. Robyn.
Winslow says:
In my opinion, the Energy 22 is one of the greatest alltime speakers. The tweeter without peer. Two areas of improvement, the bass port and the boxy cabinet were addressed to some extent in the Connoisseur.
April 16, 2010, 8:20 pmTim Wat says:
Greetings, Dave Weiser of Kurzweil spoke glowingly of your speakers on the Keyboard Mag forum (of which I’m a member) so I viewed your product with detail. Besides being a jazz pianist, I am a recovering audiophile. Used to run vinyl through Magnepan 3.5Rs. Loved the enormous width and physical weight of the Maggies (especially on acoustic music), not so excited at low volumes or on painfully bright mixes like classic rock. And they sure required a healthy high-current amplifier to get to “speaking” volume. Still have my VPI turntable, but got rid of the Maggies and Plinius amp and thus am looking for quality speakers. The only quality speakers I owned prior to the Maggies were small Von Schweikert two-way monitors (I still own them), which are wonderful near-fields but obviously cannot resolve the lower octaves like a 6 foot high planar.
I provide that context to ask these questions:
1) As you know, the audiophile marketplace is replete with transducers claiming complete transparency, breathtaking soundstage, etc. Yet every speaker I’ve heard so far has wonderful strengths and some admitted weaknesses. Knowing my historical preferences, can you comment on what my experience with your speakers might be?
2) How efficient are your speakers? Do they require a recommended minimum “floor” of power rating to “speak”?
3) Some bass-downfiring speakers I’ve heard in the past seemed to present a “disconnect” between, for example, the speaking length of the low string on an upright double bass and female vocals (for instance, in a jazz vocalist with trio recording). Can you comment on how your speakers avoid this phenomena…or perhaps I just imagined all that in my head?
Thanks so much, Winslow. I’ll check in eagerly for your reply.
Regards,
Tim
April 17, 2010, 8:07 pmWinslow says:
My preference is that speakers have wide dispersion at all frequencies. The Magnepans do not. Listeners who listen mostly for stereo imaging generally speakers which are more directional.
April 20, 2010, 7:32 am87 dB; 30-200 watts per channel.
The deep bass emanates from a forward facing vent at the bottom of the speaker. The frequencies are so low that there is no possibility of detecting where the source is.