Tech evaluation of the Iron Driver Loudspeakers

[mzisserson]

Re: Tech evaluation of the Iron Driver Loudspeakers

There's something that concerns me in this discussion and I'd like to address it somehow for the next Iron Driver.
It looks like the designs targeted for "vivid" sound as Mr.Focht described it, tend to score higher in the short term listening tests. I would certainly hope that this will not turn in to a tweeter level and mid-range level wars with total disregard for BSC. After all, the objective of this shootout is not only to take the first place but also have a speaker, worth reproducing. This statement is not at all a critique towards winning speakers. David Crew for example send us a concept which he used to create his design. I completely agree with his line of thoughts and perhaps he could share it with the rest of the members. I myself justified raised response of the tweeter by the preferred seating at live events. So, it is something to think about and probably try to even out or neutralize, so this competition does not become a 15min wining race.

It was one of the items my speaker suffered the worst from since I had the oppsite of a tilted up top end. Flat out to 13K before a soft roll off on axis (as many would say is preffered) did not bode well when in the context of a large room, away from boundries. I do not think ANYONE purposefully built in tilt, and if they did that was a good idea taking into account the application, but this is where the subjective and objective does not always agree. The tilts, mind you were very suble if you look at the measurements. My perception of Ryan's speaker was not tilted. Kenny's sounded tilted to me. I am guessing power responce and phase need to be conidered as well as I found the imgaging on Ryan's speakers to be exceptional. The only other ones in the leage were Daves and Mine IMHO. It was the difference between being into the room and speaker-back. Good discussion!

[ryanbouma]

Re: Tech evaluation of the Iron Driver Loudspeakers

I am guessing power responce and phase need to be conidered as well as I found the imgaging on Ryan's speakers to be exceptional. The only other ones in the leage were Daves and Mine IMHO. It was the difference between being into the room and speaker-back. Good discussion!

Thanks.

So then what measurements or design philosophy give us good imaging? Our speaker actually had about 30 degrees of phase misalignment through the cross over. BUT, the phase was very linear and only wraps once around 400hz and is darn near 0 degrees at the critical cross over point. Maybe imaging isn't phase related at all? Maybe this question deserves a separate thread :eek:

Model used measured phase



BTW, I have a slightly better cross over than this with perfect phase, but it breached $200 by about $5.

[mzisserson]

Re: Tech evaluation of the Iron Driver Loudspeakers

Thanks.

So then what measurements or design philosophy give us good imaging? Our speaker actually had about 30 degrees of phase misalignment through the cross over. BUT, the phase was very linear and only wraps once around 400hz and is darn near 0 degrees at the critical cross over point. Maybe imaging isn't phase related at all? Maybe this question deserves a separate thread :eek:

Model used measured phase



BTW, I have a slightly better cross over than this with perfect phase, but it breached $200 by about $5.

This is the thread to discuss all of this in. What I see is good phase tracking where it counts. So what defines "good" phase? Normally tracking perfect through the x-over region, but maybe a little difference is a good thing. I have seen them as well wrap exactly at the x-over point. HUGE reverse nulls and sound great, but maybe there is more to gain by straying away from this rule, a little? I would love to build some sort of relationship between "perfect" phase and the effect on imaging, etc. Like flat on axis FR, it is one picture to the puzzle, but maybe one best viewed from a distance? Looking at the x-fer function of your speaker, phase and FR, I would have stopped there too (if I even got there).

[DE Focht]

Re: Tech evaluation of the Iron Driver Loudspeakers

Easy now... the phase on my design seems to be one of the best, and it got last place. Granted, the FR looks like a view of the Denver horizon at sunset... :eek:

You are correct, your speaker does have the best phase but unfortunately it seems to deviate in others areas enough that you superior phase was not fully capitalized on. Having not heard your speaker and SIMPLY LOOKING AT THE DATA PROVIDED...this is an observation from afar, so its validity is limited and I am in no way trying to be critical simply copying my comments from those that were there. Dave's phase is 100% better than everyone elses, minimum.

Phase is very important, it can change a piano strike "ting" into a piano "ning", can erase the initial pluck of a guitar string. My little 3 ways when measured on the amplifier they were designed on are +5/-15 degrees from 500 hz to 4000 hz. The rate at which the phase/frequency is changing is what is critical not what your absolute phase is at any giving frequency. With my Cambridge Audio integrated not as well by about 30 degrees. (BTW last time I measured the speakers was 5 years ago, and no longer have the data) working on build thread and will have new measurments soon.

IF I put my speakers on an ordinary amplifier with a DC coupled output stage and a phase deviation over the 20 to 20K range of 120 degrees or more, my speaker begins to have sibilance issues. So the rate of change is what is critical in phase not the absolute value at any given frequency.

As for "better" imaging combining phase change and amplitude again I use any audiophile speakers Thiel, Wilson, Sonus Faber (see Stereophile, Soundstage etc. measurements)....you can see the tricks to having the speaker be uber detailed and uber imaging...which these 2 go hand in hand. These tricks are why audiophile speakers are not flat. Have to sell those speakers in 15 minutes...or less with minimal salesperson input.

Speakers that have excellent phase and are very flat, do not image as "vibrantly" and as "large" as speakers with these "adjustments"
"Image depth" is seriously compromised by a speaker having excellent phase and amplitude characteristics. Amplifiers can also factor into the imaging game, again amplifiers that purposely make their square wave performance ring and have steep phase angles through the midrange can play havoc with or flatter your speakers performance.

[mzisserson]

Re: Tech evaluation of the Iron Driver Loudspeakers

Amplifiers can also factor into the imaging game, again amplifiers that purposely make their square wave performance ring and have steep phase angles through the midrange can play havoc with or flatter your speakers performance.

You you make this "excellent" speaker with "perfect" "phase" "and" perfect" "response" and "tings" not "nings" and it still sounds poor, and you want to blame the amp? Sounds more like a justification in case the great point you make does not work. If it was that easy, or that way, you would not have to qualify it with something to blame. I don't buy it and if a speaker is truly good, it will perform well in many different environments from ideal. Many entry's in Iron Driver proved that. So have the Overnight sensations (not my favorite speakers, but heard a few iterations in many different environments and they transcend their environment), Levitations, Beasties, and other great designs. I get that the amp/speaker relationship is extremely important too, but it is the smallest picture of the equation to have that much of a gross impact save a transformer coupled tube amp. I have heard many "great" speakers get unwravled when the electronics start to outclass them. How do I know it was the speakers? Multiple amps yielded the same effect yet a few other pairs were able to rise to the occasion on any amp. It is what happens when you work at a HIFI shop and you get to play with tons of gears over the coarse of several years. But of it works for you, that is fine too. I look at your signature and you have seems to find you path to audio happiness, which is really all that matters, but you need to sell me a bit harder before I buy into "uber detail and"uber imaging" going hand in hand. If that was the case the Spica TC 50 would suck, and is one of the best imaging speakers ever created.... It just has no resolution or bass.

Edit: I am not trying to start trouble by what I said, but I am unsure that is the end-all answer to everything. Like Flat on axis FR, it is a somewhat important attribute, but it needs to be part of a while, not an absolute.

[r-carpenter]

Re: Tech evaluation of the Iron Driver Loudspeakers

I wouldn't go that far with the phase as well and please, also keep in mind that we only have impedance phase not phase tracking of each individual driver. So, while the conclusion can be made and generalized about type of the crossover, one cannot just precisely define what each drivers phase is like. If we want to compare speakers based on phase alone, minimum phase from each driver needs to be extracted.
I also can't subscribe to the notion that changes in the crossover design causing phase variances will drastically change perception of the loudspeaker. Perhaps through creating off axis 0 and spikes and there for changing arriving signal through summed up frequency response. But then again, there's a question of line arrays which have superb imaging, depth of sound-stage and should have horrible phase tracking and step response.

[DE Focht]

Re: Tech evaluation of the Iron Driver Loudspeakers

You you make this "excellent" speaker with "perfect" "phase" "and" perfect" "response" and "tings" not "nings" and it still sounds poor, and you want to blame the amp?

Edit: I am not trying to start trouble by what I said, but I am unsure that is the end-all answer to everything. Like Flat on axis FR, it is a somewhat important attribute, but it needs to be part of a while, not an absolute.

Please understand, I'm not blaming anything! I am pointing out that the speaker is not the only device that can have phase problems that effect the sound of the speaker / system. Without getting into an SL disertation just sketching out what my research has revealed. Amplifier flaws are invisible to most of us because it requires a whole other set of tools to measure them. Unfortunately Stereophile measurement seem to lack the resolution to really see the square wave performance other than when it is rolled off.

compare these 2 speakers responses....almost cookie cutter

http://gr-research.com/spicatc-50upgrade.aspx


http://www.stereophile.com/content/s...r-measurements

a more subtle application, looks a little like our winner's on axis frequency response,

http://www.stereophile.com/content/j...r-measurements

Roman; I was under the impression the phase information was derived from a microphone measurement, this would be the output phase of the speaker system relative to the phase of the line level reference loop of the measurement system itself.

And if I understood you correctly in your post immediately above, I want to confirm that I was saying the more technically perfect speaker will not image as well as (not all mind you) other speakers with the "right" deviations. See examples. Keep in mind that this is in a typical domestic listening room. The rules change when the room begins to become as technically perfect as the speaker.

[mzisserson]

Re: Tech evaluation of the Iron Driver Loudspeakers

Please understand, I'm not blaming anything! I am pointing out that the speaker is not the only device that can have phase problems that effect the sound of the speaker / system. Without getting into an SL disertation just sketching out what my research has revealed. Amplifier flaws are invisible to most of us because it requires a whole other set of tools to measure them. Unfortunately Stereophile measurement seem to lack the resolution to really see the square wave performance other than when it is rolled off.

compare these 2 speakers responses....almost cookie cutter

http://gr-research.com/spicatc-50upgrade.aspx


http://www.stereophile.com/content/s...r-measurements

a more subtle application, looks a little like our winner's on axis frequency response,

http://www.stereophile.com/content/j...r-measurements

Roman; I was under the impression the phase information was derived from a microphone measurement, this would be the output phase of the speaker system relative to the phase of the line level reference loop of the measurement system itself.

And if I understood you correctly in your post immediately above, I want to confirm that I was saying the more technically perfect speaker will not image as well as (not all mind you) other speakers with the "right" deviations. See examples. Keep in mind that this is in a typical domestic listening room. The rules change when the room begins to become as technically perfect as the speaker.

Alright.. I see where you are going. It is no doubt true, but are we ready to take this beyond speaker yet? I certainly am not! I want to find out with speakers first.

[r-carpenter]

Re: Tech evaluation of the Iron Driver Loudspeakers

Roman; I was under the impression the phase information was derived from a microphone measurement, this would be the output phase of the speaker system relative to the phase of the line level reference loop of the measurement system itself.

This is impedance phase derived by the software (sound easy in this case) through the voltage divider probe, in and ref. Stereophile's measurements show it as well for different speakers, even in your examples. Acoustic phase derived from mic response would show a relative phase and how would you get a correct minimum phase for a two way loudspeaker from that? HBT will work but again, what would be the purpose?

[DE Focht]

Re: Tech evaluation of the Iron Driver Loudspeakers

This is impedance phase derived by the software (sound easy in this case) through the voltage divider probe, in and ref. Stereophile's measurements show it as well for different speakers, even in your examples. Acoustic phase derived from mic response would show a relative phase and how would you get a correct minimum phase for a two way loudspeaker from that? HBT will work but again, what would be the purpose?

Yep forgive me; just a crossed wire in my thinking and typing

[peepaj]

Re: Tech evaluation of the Iron Driver Loudspeakers

First of all Congratulations to Dave for his first place finish and unique speaker design.
Also thanks to Mike and Roman for putting on this event, and all others that contributed to make this a success. Congratulations to all contestants. I hope everyone had a great time.
Thanks to mike, roman and ben (wolf) for the encouraging words and a special thanks to roman for all the work he did measuring and posting the measurements and repacking speakers. Wish I could have been there to thank you in person.
Update on Grandson, he is now home with he’s parents (home renovations done) and doing good in fact last doctor visit they did a echogram and said the right side of the heart started working and o2 levels increased by 10%. Now we wait until next surgery sometime between Dec. and Feb.
One last thing I have a tweak ready to go after I get speakers back, also 2 builds in the works and will start a thread on them soon. Here’s a few teaser pics.

[johnnyrichards]

Re: Tech evaluation of the Iron Driver Loudspeakers

Is that the 4" Peerless buyout there?

[peepaj]

Re: Tech evaluation of the Iron Driver Loudspeakers

Yes it is

[johnnyrichards]

Re: Tech evaluation of the Iron Driver Loudspeakers

Yes it is

I am working on (among a thousand other things) two pairs of little monitors using those right now, I also used them in a repurpose of a cheap eBay speaker. They are pretty nice

[David Crewe]

Thanks to all,
David