Troels' Jenzen Seas Build

[jim1961]

I went to the Zaph Audio site and he said he measured at 1/2M @ 92db. So thats what I did also. Was curious how my current speaker compares to the Jenzen.

I guess the thing that jumps out first is the 3rd order distortion. Then the 5th order higher than the 2nd order in places. While the 3rd is still in the -50db range, its a good deal higher than the 2nd order. Hmmmm. Dont know how to interpret that really

On the internet, one site claimed it was a red flag if the 3rd is higher than the 2nd. I notice on the Jenzen this is true from about 1.4k to 1.8k, but not by much.

Overall, the Jenzens distortion figures are much better than my little satellite ( Dynaudio d21af / Vifa P17WJ-00-08 ).

[JonMarsh]

The only thing I would describe as a red flag is when you have high order distortion products at a high level. For a speaker, they should be at rather lower levels than 2nd and 3rd.

2nd order distortion is a measure of asymmetry in the motor design- that is, a nonlinearity depending on the direction of travel, usually deriving from the motor design, a suspension that offsets the voicecoil from dead center, asymmetrical compliance, etc. 3rd order is the symmetrical increase in nonlinearity in either direction of travel- usually due to BL product fall off, suspension nonlinearity, etc, acting uniformly in both directions. A driver can have substantial 2nd order distortion even at relatively low output levels; OTOH, 3rd order should be monotonic and level related, increasing gradually with output level. An exceptionally well designed driver will have lower levels of 2nd order than 3rd- but this is rarely the case. While both are somewhat musically consonant on pure tones, with multi-tone drive, the sidebands get higher and higher in IM the higher the HD is. So, high levels of 2nd are not a good thing. That's one of the failings of most SS tweeters, for example, though to be fair, in many cases they still have lower total 2nd order than other tweeters. I have measured woofers with lower 2nd order than 3rd, but usually with unusual motor designs, like the Jantzen clones of the Morel or Dynaudio woofers, and the Aurasound woofers.

[jim1961]

The only thing I would describe as a red flag is when you have high order distortion products at a high level. For a speaker, they should be at rather lower levels than 2nd and 3rd.

2nd order distortion is a measure of asymmetry in the motor design- that is, a nonlinearity depending on the direction of travel, usually deriving from the motor design, a suspension that offsets the voicecoil from dead center, asymmetrical compliance, etc. 3rd order is the symmetrical increase in nonlinearity in either direction of travel- usually due to BL product fall off, suspension nonlinearity, etc, acting uniformly in both directions. A driver can have substantial 2nd order distortion even at relatively low output levels; OTOH, 3rd order should be monotonic and level related, increasing gradually with output level. An exceptionally well designed driver will have lower levels of 2nd order than 3rd- but this is rarely the case. While both are somewhat musically consonant on pure tones, with multi-tone drive, the sidebands get higher and higher in IM the higher the HD is. So, high levels of 2nd are not a good thing. That's one of the failings of most SS tweeters, for example, though to be fair, in many cases they still have lower total 2nd order than other tweeters. I have measured woofers with lower 2nd order than 3rd, but usually with unusual motor designs, like the Jantzen clones of the Morel or Dynaudio woofers, and the Aurasound woofers.

Thanks for making this issue more clear

[sdl2112]

+1 :T

As far as my distortion setup, I measured at about 20 inches, no smoothing (SoundEasy doesn't provide any for nonlinear tests) and input voltage was about 1.25V.

[Steve Manning]

I had better lighting for pictures today so here's a few glamour shots

First I needed to remove the drivers to add some damping material. Even with closed cell foam gasket the drivers were still hard to remove...so here's how I did it. Insert a wood screw to catch the frame only...the pic shows the rest
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Nice pictures Scott, are you going to send any over to Troels for his site? I'm with Jon I think he would be pleased with the job you've done. Cool trick on getting the drivers out ...... I talked with one of our machinists at work about tapping some threads in a couple of the holes to get the speakers out, (I was worried about cracking issues) he said go for it, so that's on my to do list.

Is that an A21 I see in the bottom of your rack? I came so close to buying one from Audiogon but ended up getting a good deal on a baby Halcro instead.

[sdl2112]

Thanks Steve!...Yes I plan on sending some pics to Troels soon. I still need to make a bottom cover then I think I'll be done.

Yes that is an A21, very nice amp, I also got it from Audiogon. I upped the bias current so it has a little more class A operation. Stock was very conservative. I also have a modified Forte Model 4A I want to try it with.

[Leeuwarden]

Your on Troels site now! Congrats!

[sdl2112]

Yes I am...thanks for noticing. He didn't use what I thought were some of my best pics...I guess I sent him too many I hope you get to start on yours soon.

[Leeuwarden]

Working on it :-)

[sdl2112]

Listening to...

Happy the Man - Crafty Hands... It's nice to discover new/old music. How this band escaped me for so long, I don't know...If you like Progressive rock, give it a listen...the title track will test your speakers...:T

[jim1961]

Listening to...

Happy the Man - Crafty Hands... It's nice to discover new/old music. How this band escaped me for so long, I don't know...If you like Progressive rock, give it a listen...the title track will test your speakers...:T

I have a copy of this one, but there is no track called "Crafty Hands", so I am not sure which track you mean by "title track".

I would say "Ibby it is" is my fav track on that one. Thanks for the reminder. Hadnt listened to that one in a very long time (got way too much music).

I also have their 1st album released a year earlier

[sdl2112]

Off to their new home...

So it worked out best for me and my brother for him to pick up the speakers today...I made quick work of the bottom covers as he traveled 2.5 hrs. It's bitter sweet to see them go as they never sounded better after he suggested room placement changes. Good thing they were not much bigger or else they would not have fit in his...ummm Honda Fit. Jim, I look forward to your listening impressions in your house and I will see you up there in a couple weeks...enjoy:T

Last construction pic...8O


Bottom pic


Nice and cozy

[benthe8track]

Those look fantastic, great attention to detail!

[JonMarsh]

Nice fit in the FIT! Any bigger and you'd need an Element like mine!

Jim should really enjoy these...

[jim1961]

In their new home

[sdl2112]

Those look fantastic, great attention to detail!

Thanks!

[Steve Manning]

Scott now you've got space for the next build :P ...... Again very nice build, I'm sure it was tough to give them up.

[sdl2112]

Nice fit in the FIT! Any bigger and you'd need an Element like mine!

Jim should really enjoy these...

Note to self...measure car size before making speaker

So will yours fit if you glue the cabinets together?

[sdl2112]

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In their new home

Well that looks weird...I'm expecting to see them in my living room when I get homeh:

[sdl2112]

Scott now you've got space for the next build :P ...... Again very nice build, I'm sure it was tough to give them up.

Yes I have ideas and I'm already changing my mind...got to stop doing that. Yes it was difficult to give them up...maybe it's like your first job or first girlfriend :W I tell you what though...I will not be giving away my next ones

[dar47]

Excellent build! Nice to see bothers working together instead of duken it out.

Now I want to see you put those great cab conversion skills into a fresh build for yourself

[JonMarsh]

Note to self...measure car size before making speaker

So will yours fit if you glue the cabinets together?

Interesting question... with baseplates, the Isiris are about 63" tall. The interior dimension of the Element best case is about 5' 5", or 65". In theory. Have to check if that's with the seats pulled up all the way or not. then there's the width- about 43" for the cargo area, less a little bit near the wheel wells. My nominal cabinet depth is 17", but that's not including the angle geometry... I have some calculation and tests to do!

I took a pair of Ardent's, each strapped to a hand truck, to Denver and back, and at the time I thought they were kind of big... Hah! They're mini-monitors compared with the Isiris!

I also have some special 3M non skid tape just received from Amazon which could be applied to the bottom of the top modules so that they could be made "non-slip", after a fashion. Might be the most practical thing to do.

I'll know more after I work out transporting the lower cabinets to GF's for finishing this weekend. It's going to be an interesting week...

[jim1961]

[JonMarsh]

Alright!! Any preliminary impressions or final thoughts? :W

[jim1961]

Several actually.

Last night, I pulled out all the plugs. I decided to see how far 100 watts would take these speakers. It seemed no matter how loud I went, they never got loud. That is to say, at no point did my ears crave for my fingers in them. At first, I was begiining to think that maybe the efficiency was lower than I thought. Today I got out my RS digital meter, put it on "C" weighting, fast response, and turned on the max button. I turned it up to the point just below any signs of strain. The meter was reading in the 102-104db range. This is at the listening position 102" from the speakers mind you. I suppose whats going on is that typically when speaker gets a bit shrill is when I judge it to be too loud. But these speakers never get shrill, at any volume level. They just seem to beg for more.

While I could say many additional things about them, this one kinda addresses them all. A speaker that is well mannered, neutral, and behaved at all times.

Using this calculator http://www.sengpielaudio.com/calculator-distance.htm I plugged in 88db for 1m, figured my listening distance to be 2.59m which translates to a 8db loss due to distance. So 80db at 1w one speaker driven = 100db at 100w one speaker driven. Add another speaker (+6db) and I am guessing my theoretical top volume peak to be about 106db. So 102-104db is probably about right for this speaker with my amp at my listening position for sustained peak output. Not bad

Back to the speaker. I suppose its most impressive feature is in the mids. Wonderfully transparent. Its like the soundstage extends forever. Slightly warm and robust. Yet gentle to ears.

It seems a bit more dynamic as well. I suppose all those expensive crossover components play a role here in limiting any kind of compression.

[sdl2112]

Hey Jim...about time to update your avatar :B

I had similar impressions...very neutral, 3 dimensional, I never even bothered playing with the tweeter level. I kept wanting to turn it up. Of course you get to the point where the bass runs out of steam but for a single 10" I think it does pretty well. At first I felt it had a little too much energy in the low mid-range but after moving them further away from the rear wall it sounded very balanced. I never heard "Heart - Little Queen - Love Alive/Sylvan Song/Dream of the Archer" so good...among many others :T

[Steve Manning]

You guys are making me jealous ....... I can't wait to find out what my build is going to sound like. I wish those elves would kick it into high gear and get that bondo and sanding work finished !!

[sdl2112]

Excellent build! Nice to see bothers working together instead of duken it out.

Now I want to see you put those great cab conversion skills into a fresh build for yourself

Thanks for the complement dar47 and yes no duken it out among brothers...which is also why I like this forum. People here are very helpful and civilized.

You guys will be the first to see my fresh build :T...as soon as I figure out the details...

[Leeuwarden]

Hey Jim...about time to update your avatar :B

I had similar impressions...very neutral, 3 dimensional, I never even bothered playing with the tweeter level. I kept wanting to turn it up. Of course you get to the point where the bass runs out of steam but for a single 10" I think it does pretty well. At first I felt it had a little too much energy in the low mid-range but after moving them further away from the rear wall it sounded very balanced. I never heard "Heart - Little Queen - Love Alive/Sylvan Song/Dream of the Archer" so good...among many others :T

Now thats what I wanted to hear!

[jim1961]

Hey Jim...about time to update your avatar :B

Took care of that

[sdl2112]

I see...very nice :T

[jim1961]

This is the in room at listening position FR response. I used 1/24th octave smoothing.

[JonW]

Scott,

Wow. I just had a chance to read through your thread here. Very impressive craftsmanship! My hat is off to you. The tips on a spray system might help me in the future. It’s something I think about trying some day. I’d love to hear those speakers. I bet that they’re great. Wonderful build!

[sdl2112]

Scott,

Wow. I just had a chance to read through your thread here. Very impressive craftsmanship! My hat is off to you. The tips on a spray system might help me in the future. It’s something I think about trying some day. I’d love to hear those speakers. I bet that they’re great. Wonderful build!

Thanks Jon! I definitely recommend a spray system...It's easier than I thought it would be to use and with better results...so it was a win-win

[Carl V]

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This is the in room at listening position FR response. I used 1/24th octave smoothing.

That is an impressively clean plot.
Subjectively, how do they sound?
I acknowledge we all hear differently.
we have all had differing past experiences.
and All speakers are colored imho. none sound
like the live event...imho. So, what are your thoughts?

[jim1961]

That is an impressively clean plot.
Subjectively, how do they sound?
I acknowledge we all hear differently.
we have all had differing past experiences.
and All speakers are colored imho. none sound
like the live event...imho. So, what are your thoughts?

Green = previous plot
Red = latest plot

I am still playing with it. Despite the 220hz null being a bit deeper (I cant seem to find out what I did that day), I have made the mids a bit more even and smooth, and removed a bit of the high frequency energy by adding 2.8 ohms more resistance on the tweeter. I also added another layer of carpet in front of the speakers, adjusted the sub x-over, and built a better floor bounce blocker.

Having said this, I felt things were a bit too bright before. Subjectively, I am very happy with things overall. I am splitting hairs at this point I think. Its hard to separate the room from the speaker. I have been working at treating the room for over a year, and of course when I change the room, I change the sound. Some of the brightness I removed wasnt the speaker at all, but a strong ISD termination peak adding about 1.5db after 2k. Again, what the room is doing affects my perception of the speaker.

I feel the strength of the speaker is the mid/tweeter integration. Quite seamless. Quite transparent. The speaker itself has become mostly invisible. It should be noted also that a sub is helping with things below 40hz.

[jim1961]

Scott,

I’d love to hear those speakers. I bet that they’re great. Wonderful build!

If you ever get to Texas, let me know

[jim1961]

Wasn't sure where to put this so I thought id show how these speakers have translated into the room. Ive been fiddling with the FR and ETC for 6 months now and seemed to have hit a wall. Was wondering if I should be happy with my results. or if not, what needs attention or could be better?




ETC (24ms blast there by intention)



Frequency response at listening position at 1/96th octave smoothing, 250ms window.

[jim1961]

REW spectrogram. I have a sub that crosses over at 40hz. Odd how it shows up at 45ms. ????

The sub is placed behind the LP. Having just figured out how much distance 45ms is (about 50'), it seems its traveling the length of the room and bouncing off of the front wall before arriving back to the LP.




Waterfall

[JonMarsh]

Wasn't sure where to put this so I thought id show how these speakers have translated into the room. Ive been fiddling with the FR and ETC for 6 months now and seemed to have hit a wall. Was wondering if I should be happy with my results. or if not, what needs attention or could be better?


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ETC (24ms blast there by intention)

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Frequency response at listening position at 1/96th octave smoothing, 250ms window.

Is the dip centered around 225 Hz a function of the anechoic response or the room interaction? It's actually pretty wide for the latter, I'd think...

Other than that, looks pretty dang nice, bitty the drop in the 200 Hz area corresponds with what is usually referred to as the power region for classical symphonic music as well as key upper fundamentals in many other kinds of music- should be fairly audible. how's it sound to you, compared with reference grade headphones?

[jim1961]

Is the dip centered around 225 Hz a function of the anechoic response or the room interaction? It's actually pretty wide for the latter, I'd think...

Other than that, looks pretty dang nice, bitty the drop in the 200 Hz area corresponds with what is usually referred to as the power region for classical symphonic music as well as key upper fundamentals in many other kinds of music- should be fairly audible. how's it sound to you, compared with reference grade headphones?

http://www.gearslutz.com/board/studio-building-acoustics/817205-my-listening-room.html

Its a very long read, but the above link is a thread where all the things ive tried has been documented. In answer to your question, I am not clear what the root cause is.

As far as how it sounds, referring to the null area, it is audible. I was trying to get a handle on the consequences of a 5 db null there. Your comment about symphonic power region is interesting and something no one has pointed out before. While I do listen to symphonic classical sometimes, my main listening is progressive rock and fusion jazz with sprinklings of new age, ethnic and folk.

[jim1961]

The green plot is both channels driven, mic aimed strait ahead as things were before. The red plot is adding "bass wings" to both speakers as illustrated in pic. This is the only thing I have tried that helps. And I am not very confident this is the right approach.

[Leeuwarden]

Have you asked Troels about this?

[jim1961]

Have you asked Troels about this?

Its definitely a room issue, not a speaker one. The near field measurements of the speaker alone look fine (these are posted earlier in this thread).

Remember, these readings are at the listening position.

[wkhanna]

Hi Jim.

Please forgive my laziness as I have only had time to scan your posts including the link.......

Given that I don't have the full picture of issues & what appear to be rather robust remedies you have thus far implemented, I am curios to know if you have considered some form of DSP?