[Jaimo]

The U15's crossover to the Eminence LF unit at 300Hz. I want to get rid of the Eminence driver altogether. Finding a suitable off-the-shelf LF unit that will do the horns justice in a Hi-fi environment is quite a challenge.

Since most subs work from 100Hz down, I don't think you will be able to find a suitable music grade sub than covers the 300 - 20Hz range. As a test, I rolled off the Eminence driver at 100Hz and tried a Polk PSW505 Sub but was not pleased with the results. The challenge is to find a LF unit that is fast with little bloat or LF overhang.

My plan is to design a LF unit that takes care of the 400Hz to around 100Hz band and then integrate a single Danley inspired tapped horn as a sub-woofer. The trouble is that a 80Hz horn is too large so I may compromise with a sealed 2 driver box. Also, a tapped horn subwoofer that goes down to 30Hz will be approx 2m long (not a problem for me as I can build this into the attic space over my listening room.

[taloyd]

Check Acoustic Elegance for their 15" drivers. They were formerly Lambda Acoustics and are considered among the finest woofers in the world. People use them as an upgrade from TAD drivers.

http://www.aespeakers.com/

Feel free to email owner John Janowitz. He'll help you out with any design/integration questions you have.

also, Nicholas McKinney is with the company, and he helped Danley design the Unity horn.

cheers,
-tal

[dwk]

The U15's crossover to the Eminence LF unit at 300Hz. I want to get rid of the Eminence driver altogether. Finding a suitable off-the-shelf LF unit that will do the horns justice in a Hi-fi environment is quite a challenge.

Unless something very significant has changed, it is not an Eminence driver - it is an 18Sound unit, I believe a variant on the 15nd920. This driver has both a neo magnet and dual shorting rings, and really is a very good driver all things considered (at US Speaker it runs $250+ per driver).

In other words, changing out the 15 form something else makes no sense unless you are going for an absolute state-of-the-art approach.   IMHO after dealing with the ~190Hz resonance, I don't conciously find the performance of the driver lacking.  I too have thought about a ~80Hz-350Hz horn, but I'm currently of the opinion that it's lots of work for little gain.

Check Acoustic Elegance for their 15" drivers. They were formerly Lambda Acoustics and are considered among the finest woofers in the world. People use them as an upgrade from TAD drivers.

Yes, this is the only off-the-shelf driver that I'm aware of that I'd consider for a swap. The lambda with the apollo motor is regarded by many as pretty much as good as it gets. However, much of the benefit in these drivers is in the ability to play high, which isn't needed in a U15 application, so I'm not in any great hurry to plunk down ~$350 per driver to see what type of improvement there is.

also, Nicholas McKinney is with the company, and he helped Danley design the Unity horn

Well, not exactly. Nick produced the kit version of the Unity in conjunction with Tom, but wasn't part of the conception/design of the approach itself. 

In any event, it's great to see other folks using the U15 - it makes me think that maybe I'm not so crazy after all.

[JDUBS]

Guys

Received and setup the Unitys.  As a refresher, I'm running these with a Transporter directly into EVS 500M monoblock amps.

To say I'm impressed would be a huge understatement!  These things are GOOD!  Never before have I heard such an effortless sound.  The speakers just sound so big and the dynamics are unreal!  And this coming from me, a former Oris 150 horn owner (dynamics of those speakers is nothing to sneeze at).

I haven't even hooked up the Swarm yet, but am impressed with the bass that is there (only goes down to 50hz or so).  Very impactful.

I'm controlling the Transporter with my iPhone.  Talk about cool!  I had considered buying a Controller, but see little need for one with the iPhone app available.  My library is .flac files securely ripped from CDs with either EAC or dBpoweramp.

This is exciting stuff!

-Jim

[JDUBS]

Hmmm...I will be putting a preamp in front of the Transporter.  The Yorkville's are so dang sensitive that you need to run the digital volume of the Transporter at a very low level (generally, but I had them rockin' the first few hours and there are absolutely NO issues when the volume is even moderately cranked!).  My wife and I noticed it during some low level listening last night.  The detail just wasn't there.  I'm attributing it to the Transporter dropping bits at low digital volume levels.

I'll try to prove this out with the insertion of a preamp (Tim Rawson Pass B1 clone).

-Jim

[Kevin Haskins]

I've not tried the Yorkville but Tom's work on the Unity concept and the servo-drive based motors was cutting edge.    Tom is an superb engineer and a really nice guy to boot. 

[Russell Dawkins]

This whole subject is fascinating in its implications regarding the role of dynamic ability in its contribution to the perception of veracity of reproduction - "high fidelity", if you like!

It is noteworthy in this thread about another speaker (the SH 50) designed by Tom Danley
http://tinyurl.com/6yksnv
participated in by Tom Danley, the designer of some the most respected PA systems in the world (who is posting as "tomservo") that Tom himself was surprised when he substituted a higher power pro amp for his 200 wpc Threshold Stasis and discovered the impression of easier dynamics even at modest listening levels when driving his 100 dB/watt SH 50 speakers in a living room environment.

That this should be audible should give anyone pause for thought and mirrors my own experience of a couple of years ago, except in this case the speakers are 15 dB/W more sensitive than mine and still the effect is audible.

I suspect this gives credence to the notion that we need an order of magnitude more amplifier power and/or sensitivity on the part of the speakers than we thought we did, and this plays a very important part in the achievement of enjoyable sound reproduction at home.

This might warrant its own thread.

[Double Ugly]

I suspect this gives credence to the notion that we need an order of magnitude more amplifier power and/or sensitivity on the part of the speakers than we thought we did, and this plays a very important part in the achievement of enjoyable sound reproduction at home.

This might warrant its own thread.

I agree x 2.

[JDUBS]

Russell, I completely agree!  I found this out on Oris 150 horns with AER BD-3 drivers (109 db / 1 watt efficient).  My Tripath amp was a powerhouse with those speakers.  My Yorkville setup is even more extreme with 1,000 watts on 98 db / 1 watt efficient speakers.  Effortlessness is absolutely a real speaker / amp combo quality that I've grown to be very fond of.  That coupled with the inherent dynamics of speakers like these make for a really great (and truly lifelike) combination.  I can't get enough of it!

I looked at some of the Danley speakers and they are quite nice....but also quite expensive.  I think the Yorkville Unity's are a relative bargain at their retail price.

-Jim

[Jaimo]

Looks like I may be wrong about Eminence as the LF unit supplier - I got this info from the Yorkville sales guy at my local pro-audio store.

Since my last post, I relocated the U215's to my 1400SQ ft unfinished Basement and was blown away by sound quality. Stereo Imaging, tonal coherence and dynamics are like nothing I've ever heard. (This includes some big hitters in Hi-Fi - top-of-the-line B&W Nautilus and the big Wilson's included) - the Rolled off LF was still an issue however.

This motivated me to move the U215's back to my upstairs listening room. Playback is via Exact Audio "bit accurate" wav's played using Windows Media Player through RME Hammerfall/ADI8DS converters directly into a Bryston 4B-ST.

I am also looking into getting a preamp although I still have trouble with paying huge amounts of money for what is essentially a buffered attenuator! 

The sound in my 16 x 12 cathedral ceiling'd listening room is not as good as in the Basement - rolled off by about 8dB @ 200Hz and drops fast - so some room correction may be needed. The Stereo imaging is also not as good. I placed A Behringer DEQ 2496 in the signal path but this took away the magic - so my next step is to work on a passive fix. The speakers also tend to "shout" when played loud. (not an issue as I keep my levels low)

The bass come up nicely if I rotate the speakers to point against the side walls so -it looks like I may need to rearrange the room so I can play with speaker positioning more freely.

Another interesting phenomenon - the sound keeps on getting better. I don't but in on the long term "burn in" c**p that Hi-Fi fans talk about so my only explanation is that my ears are adapting to the new system...(Rat-hole!)

Does anyone have any ideas on how I should proceed fixing with my LF roll-off problem?     

[Brett]

After some dialogue with dwk earlier in the year, I was all set to get a pair of U15 shipped out here, in parts if necessary.

However, I bought Nick's last set of Unity's so I'll be using those and some AE TD15X instead. Looking forward to the build over Xmas break.
http://s228.photobucket.com/albums/ee287/A9X-308/Unity/

[Brett]

Does anyone have any ideas on how I should proceed fixing with my LF roll-off problem?     

Build some tapped horn subs and xover at 50 or 60. There are many designs on the long and numerous diyaudio threads.

The 15's in the Yorkies are B&C from what Yorkville told me but I don't recall which OTTOMH.

[Russell Dawkins]

should anyone be interested, there is a sale on Danley Labs SH50 Synergy horns here, for $2500 each:
http://www.avsforum.com/avs-vb/vbclassified.php?do=ad&id=7711

17 hrs left on the sale

P.S. Cobrasound (the seller) did the comparo referred to on the first page of this thread.

[Russell Dawkins]

cobrasound also did a sub comparo here:
http://www.cobrasound.com/MDSubwoofers#attachments

On their site they show a tri-amplified U15P that sells for around $1700 and contains 900 watts of amplification - 600w for the 15" and 2X150 watts of class A/B for the 3-5" mids and the 1.7" HF driver. I am a little surprised to see that much power, but I guess they don't envisage home use for this!

[JDUBS]

Guys, next step for me with these is a triamp setup.  I'll be using a highly modded Behringer DCX-2496.

I've been pestering the Yorkville guys about crossover settings so that I have a baseline to start with.  They've tried to steer me away from going full triamp and instead recommend biamp due to:

"The horn is padded 7dB to match the 15".  This pad is not something you can bypass - it is part of the passive network that divides the HF/MF.  Altering it will destroy the phase response between the two bands."

I want to wire the three amps directly to the drivers, bypassing the passive crossover in its entirety, but it sounds like the phase issues may be an obstacle.

I do know that the horn section is 105db and the 15"'s are 98db based on the above.  Also, I know that the crossover points are 300hz and 1250hz but I don't know the slopes.  The horn section is 8ohms and the 15"'s is 4ohms.

Any ideas how I can get started with an active setup?

Thanks,
Jim

[macrojack]

I bought a dbx Drive Rack PA through Amazon.com for $398 and added the dbx calibrated microphone for another $90. $508 altogether including shipping.
If you have enough info to give Jason at dbx tech support, he can walk you through the set-up pretty well and make you very comfortable with the various steps. Once you've set all the parameters to suit you, then you run the RTA and the DRPA EQ Wizard will compensate for your room.
So far I have been very pleased with this approach.
There is a graphic EQ on the input and a PEQ on the output. So far I have only experimented with the input side. It's really kind of fun to watch the adjustments on the little screen while hearing them emit from my speakers. Very neat to have the visual correspondence.
You might find that active XO between LF and HF units and passive between HF and UHF overcomes the phase question that Yorkville raised. That's how Bill Woods advised me to use mine. I haven't yet, however. I am still only 2-way. My compression driver is a coax and I already have a protection cap and an inductor for the tweeter section so I'm planning to biwire off my HF amp one of these days.

[dwk]

When I mentioned my interest in a full dsp 3-way to Todd just after I got the U15's, he said exactly the same thing - strongly discouraging the idea of replacing the existing xover between the mids and the compression driver.

I still haven't given up on this idea, but I think you'd have to approach it very carefully. Step one for example is to pull the passiver xovers outboard, and rewire the existing speakon jacks to give you direct access to each driver. this allows quickly/easily reverting back to passive while working on the active version. Measurement is going to be extremely important; my plan (since I'd use FIR xovers) was to measure the electrical response at each driver terminal rather than the acoustic response, since it would be the best way to try to exactly determine the actual xover transfer function.  Once you accurately duplicated the stock setup, you could start to get more creative.  I'm not entirely convinced the Behringer is going to be up to the task, but I say that without knowing what the stock topology is; it certainly isn't a textbook setup, so you're going to have to spend quite a bit of time modelling the response of xover filters plus parametric sections to match things up.

Maybe I'll backtrack - step 1 really should be to measure the electrical response of the existing xover - until you know what that is, the feasibility of the entire project is up in the air.  Doing this isn't too difficult, but I have yet to actually fully open up the cabinets; if/when I do, I'll certainly try to measure.

[dwk]

oops - didn't realize at first that there were a bunch more posts in this thread that I'd missed.

After some dialogue with dwk earlier in the year, I was all set to get a pair of U15 shipped out here, in parts if necessary.

However, I bought Nick's last set of Unity's so I'll be using those and some AE TD15X instead. Looking forward to the build over Xmas break.
http://s228.photobucket.com/albums/ee287/A9X-308/Unity/

I meant to follow up and see what you had decided. Looks like you made out pretty well - the Lamda unities and the TD15's should be a great setup. 

The 15's in the Yorkies are B&C from what Yorkville told me but I don't recall which OTTOMH.

I guess one of us is going to have to actually pull a driver and have a look. We have at least three different stories; I suppose it's possible that more than one is true if they changed the driver at some point.

Does anyone have any ideas on how I should proceed fixing with my LF roll-off problem?

I agree with Brett - a tapped horn is the way to go. You'll never get deep bass out of the Yorkvilles on their own - expecting them to be standalone cabinets without a sub is asking too much.  There are other bass options of course, but tapped horns would be what I'd use assuming the space constraints worked out.

[macrojack]

What are tapped horns?

My 15 inch woofers roll off significantly below 50 Hz in a conventional vintage ported cabinet. I find that this doesn't bother me which is surprising because my last speakers would reproduce 20 Hz. From what I've read, there is very little acoustic music below 50 Hz. Quality may be more important than quantity in the reproduction of bass.

As someone pointed out, you can't make 20 violins sound like a double bass and you can't make 20 four inch drivers sound like an 18 inch woofer.

The other issue that I can't decipher has to do with room size vs. low frequency wavelength. I believe a 50 Hz wave is around 24 feet long. How can you reproduce that in a 15 foot room? And how long is a 20 Hz. wave? How big is the space that this wave requires?

[Russell Dawkins]

The other issue that I can't decipher has to do with room size vs. low frequency wavelength. I believe a 50 Hz wave is around 24 feet long. How can you reproduce that in a 15 foot room? And how long is a 20 Hz. wave? How big is the space that this wave requires?

I don't put much stock in these notions of room dimensions and maximum wavelength supported by them. It seems to me the automobile interior violates the rules. I can easily duplicate low E on a bass guitar inside any car, and at 42 Hz it's about a 27 ft wavelength - 4 times the greatest dimension.

for wavelength:  http://www.mcsquared.com/wavelength.htm