[Rick Craig]

I was reading Jim's reply to Marbles question about whether DEQX system beat Dennis Murphy's passive crossover system.  In it he states that many woofers have rising response below 100Hz and that contributes to weakness in midbass if the upper/mids are matched to bass response below 100Hz.  

Armed with this information, I changed my subwoofer low pass frequency to 80Hz from 50Hz and vice versa for the highpass on my RM40s. So, I am band passing the RM40 woofers between 80Hz to 300 Hz.  All of this is wit ...

I read the original post and what Jim has observed is due to one of three things (or any combination of the following):

1) Poorly tuned cabinet - wrong volume and / or port length.

2) Wrong passive crossover - in particular the DCR of any series inductors used as well as the effects of shunt capacitors. This is one area where an active crossover is superior because it won't introduce these changes to the response curve.

3) A woofer with a large amount of voice coil inductance - especially when the inductance starts to increase at a fairly low frequency (common in subwoofer drivers with a long voice coil).

With proper design of the enclosure tuning and crossover there's no reason why such a peak cannot be eliminated. In some cases it would be better to switch to a different woofer. An example would be if you were trying to use a driver optimized for subwoofer use as a woofer in a 3-way design. I don't know if this applies to the VMPS speakers not having measured them. Hope this helps.

Rick

[Marbles]

Rick, I guess no other speaker maker is as talented as you  


It's my understanding that the FR of the woofer gradually decreases from about 100 hz to the approximate XO point of 250 where it is about 3db down.

The speaker is still + - 3 DB over the 29HZ - past hearing range.

At the 250hz and below range, room modes are more important to me than this slight dip in FR.

[JoshK]

I am pretty sure the TC sound 10" driver that Jim is using employs a Faraday ring like the TC2+ does, and thereby does not have rising inductance with frequency.  My guess is that 3 is not part of the problem if there is one.

[tkp]

Rick, I guess no other speaker maker is as talented as you  

I think Rick is the least talented of the speaker designers that I have dealt with .  

Looking at his offering, I realized a long time ago that he has no "gut" at all.  His designs rarely stress any particular parts beyond their most linear range.  Most designers would try their best to use the least amount of parts to cover the entire audio range to keep cost down (this is where a lot of creativity comes in) but not Rick.  His phylosophy happens to coinside with my "chicken" view when purchase speaker unheard.  I guess I got bit too many times in the past believing in some thing too good to be true and turn out not to be.  In the end, it is all about trade off and value for my money so I takes the safest route now aday .

[Rick Craig]

I am pretty sure the TC sound 10" driver that Jim is using employs a Faraday ring like the TC2+ does, and thereby does not have rising inductance with frequency.  My guess is that 3 is not part of the problem if there is one.

Actually if you look at the rating for the TC 10" driver at the O Audio site you'll see that it's 2.8mh at 1K.  Please note I'm not saying this is bad - it's just inherent with drivers of this type. I imagine the large amount of moving mass in these woofers is also  responsible for some of the downward slope. Whatever the reason it could be factored in when optimizing the crossover points and slopes.

[tkp]

Actually if you look at the rating for the TC 10" driver at the O Audio site you'll see that it's 2.8mh at 1K.  Please note I'm not saying this is bad - it's just inherent with drivers of this type. I imagine the large amount of moving mass in these woofers is also  responsible for some of the downward slope. Whatever the reason it could be factored in when optimizing the crossover points and slopes.

Does any one know what version of TC10 Jim uses for the HT3?  

It could be a customed made version of the typical TC10 which designed exclusively for Jim/DM to meet HT3 design goal.  I would like to see a near field measurement of the HT3 and the data sheet of Salk Audio's TC10.

[Bingenito]

We can talk shop all day but the proof is in the sound. Anyone that wants to can come by for a listen is welcome.

If this is a flawed speaker I feel sorry for 99% of the other speakers out there.

Enough said

[tkp]

We can talk shop all day but the proof is in the sound. Anyone that wants to can come by for a listen is welcome.

If this is a flawed speaker I feel sorry for 99% of the other speakers out there.

Enough said

All speakers has flaws.  It just a matter of how much and where the trade off are.  I have not heard the HT3 so there is a possibility that I could be wrong .

[Marbles]

Does any one know what version of TC10 Jim uses for the HT3?  

It could be a customed made version of the typical TC10 which designed exclusively for Jim/DM to meet HT3 design goal.  I would like to see a near field measurement of the HT3 and the data sheet of Salk Audio's TC10.

From the www.salksound.com website:

We matched the quality of the G2 and W18 by working closely with the engineers at TC Sounds to create the 989. This extremely low distortion driver plays authoritatively deep in a relatively small enclosure. The massive motor size and 21mm of XMAX are indicative of its excellent power-handling capabilities with minimal distortion. This design allows the HT3 to operate at a nominal 8-ohms.


I feel that these salk posts are in bad taste in the VMPS circle and should be split from the main posts to a seperate thread in either the 2 channel or Salk circle.....

[brj]

Does any one know what version of TC10 Jim uses for the HT3?  

It could be a customed made version of the typical TC10 which designed exclusively for Jim/DM to meet HT3 design goal.  I would like to see a near field measurement of the HT3 and the data sheet of Salk Audio's TC10.

The woofer is already a custom model.  Specifically, the Salk Sounds HT3 drivers are:

-Tweeter: Aurum Cantus G2 ribbon,  96 db sensitive into 8 ohms
- Midrange: Seas W18EX, 91 db sensitive into 8 ohms
- Woofer: TC Sounds 989 woofer (custom specified modification of the dual voice coil TC2+ 10" woofer),  86 db sensitive into 8 Ohms when the dual 4 Ohm voice coils are configured in series[/list:u]

This has been a pretty good discussion on speaker design tradeoffs so far, but it should probably be moved to a more general circle so that all of the manufacturing parties involved can contribute freely.

[Rick Craig]

Rick, I guess no other speaker maker is as talented as you  


It's my understanding that the FR of the woofer gradually decreases from about 100 hz to the approximate XO point of 250 where it is about 3db down.

The speaker is still + - 3 DB over the 29HZ - past hearing range.

At the 250hz and below range, room modes are more important to me than this slight dip in FR.

I never said the dip was a problem. I was trying to help someone that was trying to make a change to their VMPS speaker based on the wrong information.

Where are the response curves for the HT3? You're correct, room modes will tend to swamp out a small peak in this area. A single 10" driver placed that far off the ground will be more susceptible to room modes.

[Brian Cheney]

I think Mr. Salk and Mr. Craig would be better occupied addressing the flaws in their own designs, rather than speculating about mine.  

High order filters and metal cone drivers are about as far from my way of doing things as they can possibly be.  Suffice to say I cannot abide either approach.  Consumers can listen and decide for themselves.

[Brian Cheney]

I think Mr. Salk and Mr. Craig would be better occupied addressing the flaws in their own designs, rather than speculating about mine.  

High order filters and metal cone drivers are about as far from my way of doing things as they can possibly be.  Suffice to say I cannot abide either approach.  Consumers can listen and decide for themselves.

[Marbles]

To be fair to Jim Salk, he (to my knowledge) has never commented publicly about any VMPS speaker.

He was comparing his passively XO'd HT3 with an actively XO'ed one using the DEQX.

Woodysi took the info Jim supplied from this comparison and applied it to his RM40/sub setup.

[tkp]

 Consumers can listen and decide for themselves.

This is a very good advise.  

I did listenned and decided for myself.  In the end, what matter most is owners long term satisfaction.  It is unfortunate that it will be very difficult to discuss the pros and cons of any speaker design in public without offending some one/s (ie...designers, current owners).  Maybe a discustion of a generic woofer impedance and response curve and what trade offs could be make to get the most performance out of the woofer will be much easier an hopefully not upseting any one.

I would like to learn from the designers about the tradeoffs and how they decided on these trade-offs.  I am hoping that the more educate I am in speaker design the better choice I will make for my next pair of speakers (Yes, I am looking for a third pair of speakers to anchor the last audio room in what will be my new house in December).  I wish speaker design is a little bit simplier like electronic so I can relate a bit easier.

[jsalk]

I normally do not respond to posts such as these, but I felt compelled to set the record straight with regard to two of the previous posts.

Brian Cheney:
I have not (and will never) comment publicly about VMPS (or any other manufacturer's) speakers.  The fact is, VMPS has many satisfied and loyal owners who enjoy their speakers.  In the end, that is the ONLY thing that is important.  

The second comment I have relates to Rick Craig's earlier posts.  When I talked about a rising response, I perhaps did not explain it well enough and caused some confusion.

There are no speakers in a world with a laser-flat frequency response.  But with a good design, these peaks and valleys are maintained well within a +/- 3 db range.  With the HT3's, they are typically within 1 1/2 db.

As any HT3 owner can attest, there are no problems with cabinet size, port tuning or crossover design.  I was simply pointing out that DEQX can correct for even these small diviations and the results are audible.

- Jim

[warnerwh]

A while back I decided I'd build a world class speaker. Bought the Loudspeaker Design Cookbook and started talking to people on the Partsexpress diy forum.  I'm no genius but far from stupid.  Not considering the money involved I learned trying to design a speaker is a long way from simple. I got far enough into it that added up costs.  Cost for a 3 way speaker that needs a sub would have been over 3k.  That's over 3k on a bet more or less.  Odds are high that doing this would have been a nightmare and expensive one at that.

The most important thing I learned is that it's a rare consumer indeed that really knows much when it comes to speaker design.  I've noticed a few of us are fairly knowledgeable for consumers but that's it.  If anybody would like the Loudspeaker Design Cookbook send me your address and you can have it. I'll ship for free.

I also suggest going on the Partsexpress or Madisound boards and asking people who've been building their own speakers for years how easy they think it is, at least to do well.  A two way is the most I was recommended as a novice.  That with the reality that I could spend a significant amount of money trying to get the crossover right. This after whoever I bought the drivers from plugged the info into their computer and gave the theoretical ideal.  One guy said he must have spent five hundred bucks trying to get the crossover right on his first two way.
Best of luck to anybody who thinks they can do better than anyone who's been doing it for a living for years, or decades in Brian's case.

[DSK]

A while back I decided I'd build a world class speaker. Bought the Loudspeaker Design Cookbook and started talking to people on the Partsexpress diy forum.  I'm no genius but far from stupid.  Not considering the money involved I learned trying to design a speaker is a long way from simple. I got far enough into it that added up costs.  Cost for a 3 way speaker that needs a sub would have been over 3k.  That's over 3k on a bet more or less.  Odds are high that doing this would have been a nightmare and expe ...

I couldn't have written my own thoughts any better than this! I agree completely. Previously I had romantic notions of thoroughly studying all the xo design info I could get my grubby little hands on, getting the best drivers and xo parts, and building a high-end speaker. However, the further I investigated it, the more questions I had. As I studied further to answer these questions, I came up with even more. It also became apparent that there are no texts, or even combinations of texts, with sufficiently comprehensive information to enable someone to design a high-end speaker.  

Initially I thought the typical "build a kit" response on the speaker design forums was just a brush off or lazy response. Now, I have come to the realisation that it is probably almost impossible to design a high-end speaker (especially multi-way) without a great deal of study, practise, experience, and decent test equipment and the knowledge of how to use it properly. Cost aside, this would probably take years for anyone with a fulltime job.

However, the speaker design knowledge I have gained through this process enables me to more accurately select a pre-made speaker or speaker kit, designed and tested by an expert, that suits my requirements. So, I am less likely to make costly mistakes.

[ekovalsky]

I wanted to comment on a few things outside the VMPS circle where I'm persona non grata...

I feel metal cone drivers are unlistenable, no matter how configured. They lack a crucial element for a good diaphragm material: self-damping. They ring at low frequencies and at harmonics of those frequencies. The high order filter slopes necessary to partially control said ringing have poor transient response and are a true ear strain over time. It matters nothing to me that some listeners aren't bothered by these massively intrusive problems.

I have personally heard several systems using metal cone woofers that were fantastic.  This includes my current speakers, the main channels of which use four 8" Seas Excel W22EX magnesium cone drivers per side.  They play from below 40hz to the lower midrange and do so superbly -- in fact the entire bass range is significantly more tight, weighty and tuneful compared to all my previous speakers, including two upper end VMPS models.  And even though they are in individually sealed boxes, their extension (without the subs playing) approaches the big VMPS models running full range with their passive radiators.  

I haven't heard the Salk speakers, but people whose ears I trust report they are not competitive sonically with any of our ribbon models, and I believe it.

Really ?  Who would these people be ?  Certainly none of the serious audiophiles who have recently migrated from VMPS to Salk, generally taking a big financial hit selling the VMPS.  Presumably they felt otherwise, and some even had the VMPS and Salk in the same room with the same equipment and could have sent the Salk back for a refund.  

Beyond sonics, there are some areas where there seems to be no comparison between these two brands, including overall construction technique, attention to detail, fit n' finish, and quality control.  I suspect anyone who has owned both could elaborate if asked.

[Rick Craig]

I normally do not respond to posts such as these, but I felt compelled to set the record straight with regard to two of the previous posts.

Brian Cheney:
I have not (and will never) comment publicly about VMPS (or any other manufacturer's) speakers.  The fact is, VMPS has many satisfied and loyal owners who enjoy their speakers.  In the end, that is the ONLY thing that is important.  

The second comment I have relates to Rick Craig's earlier posts.  When I talked about a rising response, I perhaps di ...

I apologize for this thread getting out of hand. It wasn't my place to help a VMPS owner and I should've left that to Brian. Please don't think Jim that I wanted to imply that this is a significant problem with your speaker; in fact, there are more important things to talk about and this pales in comparison. We have our families, food, water, and a house to sleep in tonight. Many people suffering from Katrina would love to trade places with us right now.