Interesting! First off glad you didn't say you decided to burn them
Ok from a quick search of your comments on the Silver Iris I found:
'lack of any midrange definition, and the audible resonance train from the midrange up to the top of the 15s BW which is, i am sure, the major contributor to their "boxiness"............Boxy sound = sound that sticks to the speakers. No matter the cause..........Midrange is quite lacking......suffer from the same severe cone resonances as the Silver Iris......i feel that the ability to dissappear is important. My primary speakers (Fonken with FE127eN) do a really good job, the speakers i'm evaluating right now (Silver Iris on OBs) don't.
On the back of this I played some test tones from here Stereo System Test & Analysis Tones by Nino B. and there is a noticeable dip in output at 150Hz as opposed to 125Hz and 250Hz.
My drivers have several hundred hours on them, a dustcapectomy and a phase plug which does wonders for the inbuilt resonance and peaky, hi end of the 12LTA.
I know this was designed with potential PA work in mind but I am confident they will beef up with some boundary reinforcement from both floor (or stage) and walls. My room is bigger than Sippy's but WAY smaller that ChrisB's space! They are 2/3 up the length of the room firing down the length and bass is tight and dry but I may as well try them against the wall as well as I miss the bigger badder bass I had with 2 Beta 15's not so long ago
They definitely need a tweeter up top and as noted I use a FT17H with a single 1uF cap. This seems to 'bulk' the sound up a bit as well.
I love the iPod-Dac-40yr HK receiver setup but can say the box would benefit from something bit further up the scale Especially if the ipod was playing straight from its headphone output but I can imagine you or ChrisB doing that - it sounds awful that way
Thanks for the work so far guys - Can you give us a 'for home use' critique as well when/if you are able to get them into a living room?
Get well soon Sippy
Ok from a quick search of your comments on the Silver Iris I found:
'lack of any midrange definition, and the audible resonance train from the midrange up to the top of the 15s BW which is, i am sure, the major contributor to their "boxiness"............Boxy sound = sound that sticks to the speakers. No matter the cause..........Midrange is quite lacking......suffer from the same severe cone resonances as the Silver Iris......i feel that the ability to dissappear is important. My primary speakers (Fonken with FE127eN) do a really good job, the speakers i'm evaluating right now (Silver Iris on OBs) don't.
On the back of this I played some test tones from here Stereo System Test & Analysis Tones by Nino B. and there is a noticeable dip in output at 150Hz as opposed to 125Hz and 250Hz.
My drivers have several hundred hours on them, a dustcapectomy and a phase plug which does wonders for the inbuilt resonance and peaky, hi end of the 12LTA.
I know this was designed with potential PA work in mind but I am confident they will beef up with some boundary reinforcement from both floor (or stage) and walls. My room is bigger than Sippy's but WAY smaller that ChrisB's space! They are 2/3 up the length of the room firing down the length and bass is tight and dry but I may as well try them against the wall as well as I miss the bigger badder bass I had with 2 Beta 15's not so long ago
They definitely need a tweeter up top and as noted I use a FT17H with a single 1uF cap. This seems to 'bulk' the sound up a bit as well.
I love the iPod-Dac-40yr HK receiver setup but can say the box would benefit from something bit further up the scale
Especially if the ipod was playing straight from its headphone output but I can imagine you or ChrisB doing that - it sounds awful that wayThanks for the work so far guys - Can you give us a 'for home use' critique as well when/if you are able to get them into a living room?
Get well soon Sippy
http://www.diyaudio.com/forums/atta...81731-beta-12lta-3cf-box-port-size-ez10-2.jpg
someone has tried it.
'bassrogue' be his name.
i'm about to do it on some fairly similar drivers too. worth a try tbh. given the sound feedback from the 12lta's they sound similar to my alternatives, and from my (amateur) listening i think various cone treatments will do them a lot of favours.
phase plugging mine made them into a completely different driver.
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Let's say the first date certainly revealed there's no disguising this driver's provenance as a PA driver, and yes it reminds me of many of the things I didn't care for with both the Silver Iris coax (with the cheaper compression driver) and the Hammer Dynamics Super12 - both of with employ Eminence based drivers.
I can image no real problems with these used for bass augmentation in a FAST , but even thought an emergency dust-cap-ectomy and phase plugs helped quite a bit, I still found some severe colorations in the vocal range that made them particularly fatiguing, and that have nothing to do with the bass tuning of the box.
XO them over low enough ( say 500-800Hz?) to a larger compression horn tweeter like those in link by gaf and a healthy listening distance would be my choice.
In the photo that Dave will eventually post, you'll see a pair of old KLH (17?s) mounted on the wall - while nowhere near as efficient as the Eminence, or capable of projecting 50-60ft , these are so much more listenable at my typical working / listening distance of 8-12ft
the game's afoot
I can image no real problems with these used for bass augmentation in a FAST , but even thought an emergency dust-cap-ectomy and phase plugs helped quite a bit, I still found some severe colorations in the vocal range that made them particularly fatiguing, and that have nothing to do with the bass tuning of the box.
XO them over low enough ( say 500-800Hz?) to a larger compression horn tweeter like those in link by gaf and a healthy listening distance would be my choice.
In the photo that Dave will eventually post, you'll see a pair of old KLH (17?s) mounted on the wall - while nowhere near as efficient as the Eminence, or capable of projecting 50-60ft , these are so much more listenable at my typical working / listening distance of 8-12ft
the game's afoot
Indeed!
You'll need to run the drivers in a good few hours for some of the honk & harshness die back some - even with the dustcapectomy and good phase plugs. Some advocate padding the back of the whizzer for this although I've not gone that far. Would be good to hear how you get on with them in 'home' usage that I assume most of the builders will be interested in.
I guess you and Dave may be more 'mid sensitive' than the rest of us as you specialise in smaller full range drivers/speakers and their sound - does that even make sense?
A few questions if I may: Are your comments PA-centric or general? - I think most those currently looking at these will be wondering about home use
What are the negative coloration's you hear? Is the 'healthy distance' recommendation only in PA usage or in general home use - or even a 'stay well clear' warning?
Ooh could you recommend a track that I can find (on spotify say) that we can compare notes on for the mid issues?
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The SI has a ripple train of cone resonances which bug some-people. These also hint at what a lot of people like about the SI (Jeff's comments reflect those).
I'm pretty sure that break-in and treatment will go a long way towards fixing the problems. Better room and ancilliary gear won't hurt rither.
These are coming up the mountain (i live near a mountain top -- most of the mountain under the pacific) so i can staty tuning them up ... reminds me, i need to get Bernie to bring back the RH84.
Canada is officially metric but in practice bi (houses are still buildt with 2x4s and drywall is 4' wide). You'll see me use either (sometimes both in the same sentence)
dave
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I do hope it came across that i felt the in-shop session was only useful in knowing that they make noise. The iPod front end is quite good, but the room (and placement) is not and the amp not the most suitable. If not for JRKO's prompting the session would likely have gone unreported
dave
Very much so... it really helped the SI, and i've learned some since i did those. Even just a coat or 2 of modpodge would go a long way.
Some longer plugs, perhaps similar to Mr Hendersons, are also likely called for.
dave
I would definitely not use damar -- too much and that resonance train would be worsened.
dave
Sure. We both also are well past 10k hrs of serious listening training.
Again i reiterate...i'd call last night's session a throw-away. they work and they play loud, with the conclusion "now let's get them where we can properly listen to them and start the tweeking"
dave
I do hope it came across that i felt the in-shop session was only useful in knowing that they make noise. The iPod front end is quite good, but the room (and placement) is not and the amp not the most suitable. If not for JRKO's prompting the session would likely have gone unreported
dave
My fault, I hold my hands up! Nice to know they make a noise thou!! Leave em out there for a few days blasting away and they'll change up a gear or 2
I'd love to hear more of the ENable mod and the changes to the SI sound
10k hours
thats 24/7 for a year and then most of spring thrown in for good measure. Sorry my 'stay well clear' didn't come across as light hearted. I hope my posts haven't been seen as an interrogation. I'm just itching to see what you guys can come up with to tweak them even better!
Looking at all other designs you two work on and perfect I know the work you have and will put in on this to make it really works is heartfelt and considerable
15-20 m ?! That's a lot higher distortion than I assumed. Haven't seen one up close and personal; what sort of finish is on the surround?
I'm wondering if treating it and the first inch or so of the cone and maybe the lip of the whizzer would benefit from a sticky coating like used to seal Altec/GPA or similar cloth surrounds and on some cheap paper hinged 'FR' drivers to protect them from early failure.
GM
I'm wondering if treating it and the first inch or so of the cone and maybe the lip of the whizzer would benefit from a sticky coating like used to seal Altec/GPA or similar cloth surrounds and on some cheap paper hinged 'FR' drivers to protect them from early failure.
GM
Too heavy... hence a practical revision to 15mm ply.
A very nice feature of Vectorworks. Depending on who's design i'm working on the original could be metric or imperial.
dave
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