Here is the Circuit.

Service manual

The cost of the SEAS EXEL drivers is too great for some to bear in these economic times.  I have explored the possibility of using the above drivers as a less costly alternative.

The Thiel/Small parameter are an acceptable match.  Fs is 4 Hz higher, VAS is virtually identical, and Qts is slightly lower.  I consider the mismatch however to be acceptable.  The line as built is slightly long.  However, I think the line will function well.

The SEAS CA18RNX bass/mids are $75 from Madisound, so that would be $300 for the pair.

The SEAS 27DTC Tweeters are 39.91 from Madisound, around $80 for the pair, bringing the driver coast to an acceptable $380.

Here is the pdf for the woofers.

Here is the pdf for the tweeters.

I have designed a crossover for these drivers.

This crossover is elegant and simple.  Although the pdf states that these are second order Linkwitz/Riley filters, they are actually highly customized.

The low pass filter is actually first order from 1KHz to 5 KHz.  At5 Hz, the composite electrical and acoustic roll off becomes fourth order.  The woofers are down 18db an octave above the crossover frequency of 2.8 KHz.  Req and Ce provide impedance compensation to the woofers.

The high pass filter is also first order 8 KHz to 1.8 KHz and transition to fourth order after that.  The program does not let me show R1, which changes the Q of the filter.  Note that C2 shows a resistance of 2.005 Ohms.  Now no cap will have that resistance.  So a 10 watt 2 ohm resistor needs to be placed in series with C2.

This is an easy to build seven element crossover.  You can see that the filter is first order in the crossover region, as the phase angle is 90 degrees, or a quarter cycle in the crossover region.  Also this crossover puts the tweeter 48 db down at its resonance  of 550 Hz.  So there should be no tweeter harshness.  A standard first order filter would have put the tweeter down only 14db, at resonance.  Since this is an odd order filter at crossover, it will fulfill the lobing requirements of the d’Apollito configuration.

There is also around 3db of diffraction compensation with this crossover.

Since the phase and time response of this filter is well above average, transient response should be superior.

Good parts should be used for the crossovers.  Air cored inductors and polypropylene caps, such as Solen caps should be used.

I think where funds are a problem, these drivers and crossover should be given serious consideration.

I will work on a TL for these specific woofers.  I think this design carries the promise of unbeatable value for money.  The line will end up being a little smaller than the Thor line.  Power handling will be less, but a respectable 160 watts.

I attended the SOTU event in Orlando last month.  It was an opportunity to listen to some of the equipment talked about on the Audioholics forums and see equipment off the drawing board.  Apart from my Rotel, pre pro, my Direct TV HD DVR and one Sony Bravia TV, I don’t think any of the rest of my extensive equipment list is talked about on the forums.

It was a chance to hear what is “on offer” so to speak, and make some acquaintances.  Also I attended as many of the didactic sessions as I could, but I gave up the lions share of the last day, to try and carefully evaluate the sound in the demo rooms.  By that time others had already had their chance to to hear the movies, booms crashes and explosions.

I wanted to hear the quality of the sound on offer.  In all of the rooms, I used mainly for evaluation a disc of keyboards suites by Jean-Philippe Rameau.  (Hyperion CDA 67597)  This disc is in a large series of superbly engineered discs by Hyperion devoted to the outstanding Canadian pianist Angela Hewitt.   For this disc she chose an Italian Fazioli piano. These pianos are beautifully voiced and balanced, with a very clean delicate articulation.  Recordings like this absolutely lay a speaker naked.

In a couple of rooms I played the opening of Sir Edward Elgar’s oratorio The Apostles.  The London Philharmonic Orchestra, choir, Choir of Downe House School and six soloists are conducted by Sir Adrian Boult.  This recording (EMI CDS 7 49742 2) is widely considered one of the finest recordings ever made.  It comes from the pre digital era and was superbly recorded in the Kingsway Hall before modern acoustic engineers ruined it.  Now this is a recording I’m loath to use for an audition, as only very exceptional reproducers can do any justice what so ever to it.  So I think it generally unfair practice, unless I hear a reproducer that might stand a chance, to offer this recording up.  Two were of that caliber, but unfortunately I only got a chance to play it on one.  It was played on another at the request of the demonstrator.  This recoding has a wondrous sense of space and at the same time inner detail.  It is beautifully balanced.  There is tremendous deep bass detail, which many otherwise fine reproducers just leave out. Unless you have heard these disc on a reproducer with a very extended and accurate last octave, it is impossible to know what other reproducers leave out.

The Pioneer 3-EX: –   This is a new speaker from Pioneer.  This is in a line of speakers build round a mid/tweeter coaxial driver.  This is a scaled back version of the $18,000/pair 1-Ex.  These speakers use coaxial mid/tweeter units.  The woofers have woven carbon fiber cones.  These speakers are therefore three way designs, with crossover frequencies sensibly chosen at 400 Hz and 2KHz.  They claim to be time aligned.  Nominal impedance is stated to be 6 Ohms, however with two woofers in parallel below 400 Hz, they have to be regarded a essentially four ohm speakers.  I can not ascertain that these speakers are actually yet for sale, or confirm a price.  But $6000 per pair was quoted.

Unfortunately I only got to play the Rameau disc on these speakers, but it was an extended listen.  The sub was kept operative.

I have to say I was extremely  impressed by these speakers.  They were very well voiced and balanced.  The image was rock solid and the piano placed in an entirely believable acoustic environment.  The detail and articulation of the Fazioli piano was captured nigh on perfectly  The only minor blemish, I was aware of a very slight bloating of the lower strings,  by I think the port.  However I’m used to the non resonant output from TL ports. I did notice in their movie presentation that the speech clarity was by far and away the best of the show.  Speech was still highly intelligible, even in very noisy parts of movies.  I think this is largely due to the coaxial driver.  It goes along with Chris Seymour’s presentation of his measurements on center channel speakers.

Chris Walker of Pioneer gave a figure of $6000/pair.  If that is so, I rate them very good value for money. I did not get a chance to play the Elgar, but I would like to have.  I would just love to get my hands on at least a couple of those coaxial drivers. I noted the mid range cone was very shallow, and made just about a perfect waveguide for the tweeter.

I’m not usually impressed with far Eastern Speakers, but these really caught my attention.  I though they produced the best sound of the show.  The quality of construction and finish were superb.  I understand the designer was formerly associated with KEF.

Of interest is the fact that the speakers were powered by their SC-07 receiver.  This is their mid range receiver using class D amps employing B & O ICE amp technology.  I asked about their suitability for powering four ohm loads, especially given the fact that although the speakers were nominally 6 ohm, given the fact there are two drivers in parallel below 400Hz, they had to be four ohm below 400 Hz, except for the dual bass reflex impedance peaks.  They stated that for most speakers of four ohms they will be fine but refuse to put it in print.  I asked what they would do for warranty in the event a customer had a problem.   They said they had extensive data on the loads offered by a lot of loudspeakers.  I have to say I’m suspicious of this assertion.  However they stated that if a speaker had an impedance curve they deemed unsuitable it could void the warranty.  I could get no commitment that any list of unsuitable speakers would be forthcoming.  They did however state that their flagship receiver the SC-09TX was unconditionally stable into all loads.

The Snell D7 : –  This is a two and a half way tower with a switchable rear firing driver.  It is designed round modest SEAS Prestige 6.5cm paper coned woofers and a SEAS prestige tweeter.  I have modeled these units previously, and would seem to be able to provide a level of performance beyond what their price point would suggest. I was told that these speakers retail for $4000 each, however I see they can be obtained for just under $2,200 on the Internet.  The speakers were auditioned with the sub.

I first auditioned these speakers with the Rameau disc.  They gave a very creditable performance.  Articulation and sense of space ere above average.  The lower mid and upper bass were a little more colored tan the Pioneers.  However the tonal balance was pretty accurate, with superior articulation.

I tried the Elgar disc on these speakers.  Perspective, balance and voices were reproduced well.  There as fairly good bloom on the brass.  The violins, had a reproduced quality though.  This recording has very natural violin sound, on these speakers the violins were a little wiry, and lacked softness.   The deep bass was the biggest difference between these speakers and my rig.  The deep effortless natural foundation was lacking.  The sound of the softly played tymps lacked depth of tone.  The deep organ pedals made only a fraction of the effect they should have.  However having said all that, the performance as very listenable, and had a good sense of space and perspective.  For speakers in this price range they acquitted themselves well in what is a  huge mountain to climb for any reproducer.

I could not help but notice how affected the staff were by Elgar’s music.  It seemed to affect them deeply.  Elgar was a master at conveying feeling and emotion.  So often on hearing his music, you say to yourself, “yes I’ve felt like that.”  Elgar is known only to most Americans for the march from his Pomp and Circumstance March No. 1 played at graduations.  That is a pity.

The HSU HB-1H: – These speakers at $179 each are absolute gems, and outstanding value for money.  They were being used, five of them with an HSU sub, to demonstrate the Sherwood R-972 receiver.  This receiver contains the French Trinnov optimizer.  This obviously is in competition with the Audyssey system.  This system uses a cluster of microphones for set up.  I have to say this system was able to achieve some excellent perspectives.  Also you can set it to EQ below 300 Hz only, which I think is a big advantage.  I noted on both systems the effects of EQ above the bass area were not entirely satisfactory.  The system was ably demonstrated by Jeffrey Hipps, senior vice president.

This system with its five identical speakers, was able to locate Angela Hewitt at her Fazioli piano just about anywhere in the room.  She was moved over to the right corner with a commendably realistic soundstage.

The sound of the piano was articulate and detailed and the bass better integrated with the sub than any other system.   The lower octaves of the piano were reproduced very effectively.  These speakers use a horn loaded tweeter to help achieve a superior sensitivity 92 db/1meter/2.83 volts.  Horn aberration was remarkably slight, with a trace of brittleness to the piano sound.  The speakers had a good tenor range, indicating good step response compensation, even though there is only one woofer.  The impedance does drop to four ohms though, to achieve this, again indicatiog there is no free lunch.

At Jeffrey’s insistence we played the Elgar disc.  The system was able to achieve excellent perspective.  The horn artifact marred the choral sound giving the chorus an “awe” character to their sound.  This wars especially notable in the choral peaks.  Bass was well integrated, but despite the excellent HSU subs, could not achieve the depth and authority of my system.

For speakers, in this size and price range I thought they were outstanding performers, and remarkable value for money.  Unfortunately horns are renowned for exciting higher order modes, and diffraction problems in the waveguide which become more pronounced at higher volume.

The SVS MTS-01 and Audyssey: – In this room Kris Kyriakakis from USC and Audyssey was using this SVS set up to demonstrate Audyssey.  I was able to spend some extended time with Kris.  I was convinced that the system could improve the lower octaves, however I as not impressed with what happened above that, and Kris had to do some manual over rides to reproduce the piano to my satisfaction.

The sound of the SVS system was very pleasant.  I thought the bottom end still a little embellished, despite Audyssey.  Perspective and detail were not quite of the standard of the previous system mentioned.  However I have to stress listening to the performance as very pleasant with nothing overtly standing out to overtly irritate.  At under $1000 dollars each I consider they represent good value for money.

Emotiva: – Dan Laufman and general manager Lonnie Vaughn put on a good show in the Emotiva room.  I got to spend significant time with Lonnie.  I appreciate his generosity with his time.  There was a a mouth watering amount of electronics on display.  The hood was open so one could see the standard of construction.  Emotiva’s boards, still are stuffed with through wire components, rather than robotically placed surface mount types.  Boards were not overly crammed, and components were identified on the boards.  I would think any competent service tech would have an easier time than usual for boards of modern manufacture isolating and repairing a fault.

There has been talk on these forums of reliability issues with Emotiva electronics of late, so I asked Lonnie about it directly.  He told me their failure rate as in the neighborhood of 1%.  That is very good for solid state electronics.  I have no reason to disbelieve his statement.  He was not someone who I would have thought would have glossed over a problem.  The trouble is the 1% of customers with a problem are inclined to vent on the forum.  Like the vast majority of manufacturers they do not make their semiconductors and other components.  Small levels of contaminants in the manufacture of semiconductors, have always been a problem.  This I doubt will ever be entirely solved.  Problems caused by these impurities will show up usually in the first few months of use.

Now to the speakers.  The movie demo was impressive, however I find it impossible to evaluate and know the worth of speakers on a diet of movies.  So Lonnie put the Rameau disc on the ERT-8.3 towers at the back, driven form their CD player.

First auditioning was extremely disconcerting, with no coherent image what ever.  So much so, that I had to ask Lonnie to check the phasing of the speakers.  Sure enough they were out of phase!  I don’t want to make an issue of this, we have ALL done it.  After correcting the phase, things considerably improved.  However I have to report that I found this speaker had shortcomings.  The image of the piano was still not well defined.  The speaker was not bright and had good tonal balance.  However, it had a slightly muddled quality to it.  These speakers did not create for me a believable acoustic space.  There was significant coloration in the lower middle and upper bass.  At the asking price under $800 a piece, they can not be called a disaster or even poor value for money.  However Lonnie’s laudable aim is to make a speaker excellent value for money, and not a speaker just good for the money.

I discussed my feelings at length about these speakers.  I suspect the problems are caused, by the fact that there are two mid range drivers, the fact that the low pass/bandpass crossover is 300 Hz, into the problem range for passive crossovers and some degree of cabinet resonance.  I felt that the lower crossover was particularly problematic.  The reason for using two mids, was to get sufficient spl to meet THX specs for spl.

Unfortunately three ways are hard to execute, especially on a tight budget.  In that price range, I would think they would be better off with a well executed two and and half way.

Another attendee later told me their bookshelf speaker was a real winner, and so I later returned and asked Lonnie to please wire them up, which he kindly did.  Unfortunately it immediately became apparent that the right speaker had gap rub.  Dan immediately got the blame for overpowering them.  I suspect the woofer had a dropped a voice coil turn.  However on trying to listen through the buzz I think they may well have a winner here.

On another note, the Emotiva CD player produced faint clicks on the Rameau disc, not evident on other players and my two players.  I’m just mentioning this, and don’t want to make a mountain out of it.  It is a fact of life that some discs will have problems on some players and not others.  That is why I always keep at least two players hooked up.  Simon Perry the late founder of Hyperion used to say, that the ability of a player to play a wide range of discs, was in inverse proportion to the cost of the player!

I have to say I had an interesting time in the Emotiva room.

EMP : – EMP is a division of rbh.  They had some very attractive speakers on show.  Hooked up were their prototype EF 70Ts EF70Cs and EF70, mains, center, surround/presence respectively.

The EF 70T towers have a tweeter and six nice looking 5.25 inch aluminum coned drivers.  Because of my long experience with the Jordan Watts driver, I’m very interested and partial to small aluminum coned drivers.  So I wanted to like these speakers.  I regret to have report though that in my view they are a disaster and not at all ready for prime time.

Angela Hewitt’s Fazoili piano was unrecognizable.  There was no sparkle, there was a gross excess of lower mid range and upper bass, giving this delicate instrument a bloated presentation.  The whole presentation of the piano had a flat dull presentation.   I noted that the movie presentations were at much too high a level, often a tip off there is something to hide.   Movie voices had an unnatural quality and clarity left a lot to be desired.  In short I could not live with these speakers at all.  If I ordered them, they would ship out on the next UPS truck.

I think speakers are making great strides, and I was impressed as much by the similarity of the speakers as differences.  However EMP was”odd man out” by a mile.

The designer Shane Rich, who also was generous of his time, was obviously disappointed by my assessment.  I did suggest that he effectively has a line source with his six drivers with the problems that entails.  I shared with him that I encountered similar problem using the JW drivers as a line source down into the bass.  I suggested that, the upper frequency limit of each driver be reduced as you move down the line.  This might well clean things up.

I enjoyed Chris Seymour’s exhibit, and enjoyed talking to him.  His 1000 watt class D mono blocks using class D ICE amps built by B & O have a superb build quality and a very classy finish.   They ooze quality.  As stated above, Chris gave a well researched presentation on the shortcoming of horizontal MTM center channel speakers.  Those of you who know my posts, will know that I have posted about this on quite a few occasions.

As far as other lectures, of those I heard, I would commend Jeff Pravia of Epson on projectors.  I particularly enjoyed Jonathan Novick’s presentation from Audio Precision on Amplifier measurements.  His data was obtained with resistive loads.  I of course made a plea for tests with loads having up to 30 degree phase angles.  The THX, and Audyssey presentations were also notable.

This SOTU event, I thought was somewhat subdued as a result of the prevailing eccenomic conditions.   It would have been nice to have had more presenters.  Gene thought that the economy will have to show good signs of recovery before hosting another event of this nature.  I find that regreteble but sensible and understandable.

It was good to meet Gene and his lovely family.  At the Banquet I sat with Rickster 71, Wayde Robson, and their  wives.

I dressed daft enough to get the best male costume award.

Majorlooser is sporting the horns, I’m the Matador!  It was a great evening.