Tech evaluation of the Iron Driver Loudspeakers

[Ron_E]

Re: Tech evaluation of the Iron Driver Loudspeakers

Thanks for the advice Pete. I plan to take these to Grinnell next month and will probably have to leave them as is for now. The port is a press fit thing and wouldn't be easy to change and I have another project to finish for Grinnell. Maybe I'll just have to make an improved version down the road.

Ron

[ryanbouma]

Re: Tech evaluation of the Iron Driver Loudspeakers

I'll be interested to see CSD on ours. Given Romans comments it sounds like we could use more bracing / damping.

[r-carpenter]

Re: Tech evaluation of the Iron Driver Loudspeakers

Ok, So, here comes Matt Foster and Ryan Bouma
Over all very smooth, very flat response with mild BSC

[r-carpenter]

Re: Tech evaluation of the Iron Driver Loudspeakers

Rayn can comment on the CSD himself. As the subjective evaluations shows, it's not as important as one may think.
5k is external noise (disregard).

[r-carpenter]

Re: Tech evaluation of the Iron Driver Loudspeakers

Over all, low distortion system. Excellent crossover work and as I mentioned, seamless integration between the drivers. Smooth falling off axis response. Trouble free impedance. Don't really know what else to add.

[kenny_k]

Re: Tech evaluation of the Iron Driver Loudspeakers

I had a great experience at IRON DRIVER. Everyone made me feel like family. I was not aware how close the community is. I want to thank Mike, Roman, Jeff and everyone who attended and participated. Oh, also Parts Express for their support.
Roman, I knew about the impedance problem before the evaluation. In my haste to complete my entry, I placed the resistor after the crossover...bingo. I had problems with my little Lepai shutting down when I tested my entry, now they just drone away. Their still a little bright.

[donradick]

Re: Tech evaluation of the Iron Driver Loudspeakers

Thanks for the added explanations Roman.
I need to dig out the "Testing Loudspeakers" articles by D'Appolito have do a serious review.

[r-carpenter]

Re: Tech evaluation of the Iron Driver Loudspeakers

The starter of this mess. MikeZ.
Flat response with a smiley at the low end, probably because of the high Q woofer. Rolled off top octave inherent to the model of ring radiator, Mike have chosen.

[r-carpenter]

Re: Tech evaluation of the Iron Driver Loudspeakers

CSD shows residual ringing from the midwoofer break up. I didn't find it audible and there for problematic, but it's there. Budget is a tough cookie. Not enough $ for notch?
Nicely build heaviest box of them all. Wish Mike build it with a couple of handles.

[r-carpenter]

Re: Tech evaluation of the Iron Driver Loudspeakers

Over all, low linear and non linear distortion system. Nothing to add in the measurements. No serious issues. Well balanced, well designed and well build.

[mzisserson]

Re: Tech evaluation of the Iron Driver Loudspeakers

Will we be shown detailed ratings by the listeners? It would be interesting to see how people rated their own speakers. Like if monoiz15 really ranked our speaker low, that would be funny. And also to see how they were rated. For instance, if someone wanted a speaker with great bass and refused to run subs, perhaps the winner isn't the best speaker. Or if they wanted great imaging, then speaker X might be best. Etc. That and it would be interesting to see.

Ryan, PM me your e-mail address.

[biff]

Re: Tech evaluation of the Iron Driver Loudspeakers

Thanks for letting us play in the game, guys - I know Brian was eager to come up and meet everyone but ended up working instead (life gets in the way) and it's a long way from the Carolina beaches, but hopefully we can do this again! We would really like to hear any impressions, thoughts on our basic design etc. - any input is welcome. And if anyone wants to interpret our waterfalls as I am not versed with seeing what that performance graphic can tell us. When we get these back we will likely work on the XOs and a bit more finishing on the cabinets, I tried to incorporate some good theories on Z alignment, diffraction, cab tuning, bracing patterns to sonically minimize the box resonances, and yes, I even put handles on them, it appears to be a trend with me

Thanks again for putting this together guys, Brian and I worked away in an iterative way that hopefully will bring us something(s) really special on our next project!

[ryanbouma]

Re: Tech evaluation of the Iron Driver Loudspeakers

Thanks for the measurements Roman. A fair amount of ringing there. I wonder if Monoiz is able to get in there after the fact and brace it up better. It's his pair of speakers so it's his choice.

I wonder if he and i should start a technical thread ourselves and reveal the xo.

Glad you noticed the lack of BSC. This was for a few reasons. Matt and I didn't really set out to win anything. He wanted to learn xo design, I already had the iron driver and lots of experience with it and wanted an excuse to do another design with it. So we were creating a speaker that worked for him. I was tempting to increase BSC because I thought in a large venue it would be required. But that leads into my second point.

I usually find lack of BSC adds an excitement to the sound that comes from being a little bit forwards and more effecient.

Last, I've used this woofer a lot, and ime I find that it naturally has a full/thick sounding bottom end and lots of BSC is not required to sound balanced.

Glad you like the driver integration. 5 parts total. No NPE caps. I wonder what we could do about the lean bass. I wonder if it would be that way in all rooms. Personally I'd build it sealed and run a subwoofer. But if not, I wonder. I pushed Matt to reduce the box size, that was my fault. He wanted to make it ~40L and that may have added some umph.

[scottq]

Re: Tech evaluation of the Iron Driver Loudspeakers

Yes, awesome work Roman! Thanks so much for the extra effort and the time you've put into sharing thoughts on each!

I look forward to fixing these. The budget made things very difficult, indeed, but I wanted to stick with the primary goals and all the challenges/concepts. That said, I am certain there is room for improvement, even within the budget. The measurement woes were my own fault... the procrastinator in me let things slide way too long. I should have known better with all upgraded equipment that things wouldn't go as smooth as I planned.

I warned you about their inefficiency - tripling the moving mass really takes a hit on sensitivity! I tested and did listening on a GFA-5400 for a reality check rather than my bridged Parasound 1500A's (rated for 630 Wrms); for almost all material at enjoyable volumes in a living room, the 5400 was plenty capable... a few dynamic orchestral passages made the overload indicators flicker, but most things did just fine. They aren't PA speakers, that's for sure. Low-power receivers realistically aren't going to cut the mustard. But there are plenty of great 2ch amps available on the used market for under $300 (picked up my 5400 for $225 shipped).

I was pleased to find out that several of the songs on the demo disc were ones that I listened to on them at home... Jeff, the mixes were very well done; thanks for your efforts too

And, of course, thanks to Mike! I sympathize with the effort that goes into these events...

Be on the lookout for the Apertures v2 at SEC DIY 2012.

Regards,
Scott

[jclin4]

Re: Tech evaluation of the Iron Driver Loudspeakers

Congrats to everyone who entered and especially to the organizers, Roman and Mike who put in a ton of effort to pull this off successfully. Of course, congrats to Dave as well as the winner.

What an amazing range of designs; not one looks like the other. I really appreciate the photos, from Phil, Jay and others. I've finally been able to piece together whose speaker belongs to whom:

• scottq : 3-way with side-by-side tweeter and mid
• ryanbouma + monoiz15 : MTM with ply panels
• kennyk : MTM black finish (truck liner?)
• peepaj : Maple MT with ring tweeter
• Biff + Boroson : Large MTM with felt surrounded ring radiator tweeter
• RonE : Tall dark wood/veneer MTM with smaller ring radiator tweeter
• David Crewe : Saffrons - two part cabs
• r-carpenter : TMM layout / grey baffle
• mzisserson : 3-ways with orange edge pieces, tweeter below mid