HyperFAST - a Hypercube Based 2-Way

[xrk971]

X, an F3 of 43hz with a final qtc of .5 is tough to argue with.

BYRTT, Thanks for that tip. I do all my real time dsp via the foobar convolver plugin.

I was shooting for Q of 0.71 using the spreadsheet but visually it looks closer to 0.5. Not bad though for a 5 in woofer.

 

[gmad]

Hi BYRTT, Yes, this causes some latency. When I watch a movie, I use a convolver plugin with Media Player Classic. MPC lets me delay the video to sync with the audio so it's not a problem.

 

[BYRTT]

Hi gmad thanks hope it's alright exchange our hobbys experience, personal i more listen music than watching television so the latency no problem here. Last years very interesting DSP control had come to our power and more to come, i haven't tried yet real linear phase where the more perfect calibrated systems seems allow square wave reproduction think i read somewhere in area 50-5,5kHz. Some concern i have when thinking it over is if a track is produced/mixed at minimum phase system especially low end is some delayed but no problem as at the recording everyone musicians and engineer did monitor and mix in minimum phase domain and calibrated their played notes timing and mix after that. Now put perfect linear phase for such a track, okay the squarer wave reproduction is welcome fine for dynamics speed, but wouldn't low end be too fast and put false timing for some notes. At a time i did read a audio system reviewer complain the opposite timing problem that a certain English brand that always used 4.orden LR XO's that the low end always had timing problems in too slow played/timed notes. Present i'm fine and like the 180º error of a single full ranger from DC-15/20kHz as in headphones, the added SPL a FAST system gives is very welcome here and a gold but until further my attempts don't result transperens when switching between lower SPL EQ'ed single full ranger to FAST system, that's the hobby and interest.

 

[gmad]

Hi BYRTT.

One of the great things about dsp, as you know, is that we can make different presets that can be used for different types of recordings. Personally, I don't care for this approach and just try to make my system as perfect as I can. With respect to flatter phase response, I have noticed improvements with great recordings and no drawbacks with typical multitracked recordings. Anyway, I would rather my system reveal "flaws" in recordings than worry about which preset to use.

 

[xrk971]

Here is another Hypercube-Karlson tube based 2 way by bolexbm:
http://www.diyaudio.com/forums/full-range/223313-foam-core-board-speaker-enclosures-254.html#post4150000

Looks nice!

 

[xrk971]

RS100-4's in HyperFAST

Here is an initial attempt at getting the Dayton RS100-4's in the HyperFAST. I am still using them with a -24dB/oct HPF at 300Hz but the woofer is now running at 260Hz rather than 240Hz with the TC9FD. I applied the same peak cuts to get rid of the Hypercube induced resonances but also added a high shelf boost as the RS100 seems to have a bit less sensitivity in the higher octaves than the TC9FD. Here is the comparison of the TC9FD and RS100-4 in the same Hypercube with same drive voltage and mic at identical positions:

As you can see, the two drivers have very similar behavior in a Hypercube.

Here is the XO response plot measured 8in away at a height in between the two drivers, thus the HF will be reduced since it off axis vertically, green and blue is difference with a mild boost at 1.4kHz to flatten out the depression - sounds about the same so I prefer to leave it out:

Here is the minimum phase - 45 deg major increments (pretty good):

And here is the impulse response - note the ringing with a freq of about 15kHz. Whatever I did to the EQ is giving it a bit of a pre-ringing;

This is the result of the peak that the RS100 has at 15kHz, fortunately, that is right at the edge of my hearing so it is not bothersome. It makes the driver sound metallic - and there is a slight sibillance to metallic percussions. Not surprising as the driver is an aluminum cone. I have not tried to EQ this peak out yet, but if my experience is right, you cannot EQ out a major breakup mode of the driver. So the difference with this and the TC9FD is that it has more "air" whether or not that air is real, if you like that sort of thing, this driver delivers a shimmering high end. On the other hand, the vocals through the midrange are quite nice. I can't tell a difference between this and the TC9FD for vocals. I am listening to some tracks from Sting's "The Summoner's Tales" and it sounds very nice, similar to TC9FD but with more sibillance and airiness. I think most people would be happy with it.

 

[xrk971]

Sound clips with RS100-4 (mono).

 

[gmad]

I haven't found the 15k resonance to be much of an issue. I measured a little bit of ringing in the empty enclosure, but with a piece of foam inside (as shown below) it seems to not be an issue at all.

 

[gmad]

oops, here it is.

 

[xrk971]

I haven't found the 15k resonance to be much of an issue. I measured a little bit of ringing in the empty enclosure, but with a piece of foam inside (as shown below) it seems to not be an issue at all.

Can we see your impulse response?

 

[BYRTT]

Sound clips with RS100-4 (mono).

Listened the sound clips please take as is or make own listening, count for in reality the many more electric and acoustic playback/record chains the clips has passed before listening sound hit ones ear compared playing the track from a CD, but compare recorded tracks from same environment should be reasonable fair. RS100-4 is brand new it could need some break in time. Have a little background experience for listening xrk971 sound clips signature in that in a file library i see 34 xrk971 recorded sound clips.

Two first tracks HyperFAST-RS100-01/HyperFAST-RS100-02 is way too airy for my taste, reminds me my first listening metal cone where later the too airy signature was some decreased by a resonance and inductance filter at drivers terminals in form of LCR and CR networks.

At third track had the opportunity compare same track played by TC9FD as top in the HyperFAST system found in #6 this thread named HyperFAST-clip-01s and is also mono from one HyperFAST system. Comparing these two for me sounds as if a power amp has the electrical bias network current set too low which gives kind of airy sound and this is RS100 foot print and if the network current set higher more towards class a gives more bite and this is TC9FD footprint.

The sound clips present available when compared i prefer TC9FD signature this based on my 4 different pair of headphones sound signature leans more to TC9FD. If in time we get opportunity to compare a sound clip both drivers as single point full range in Hypercube box think be better to reveal their inherent sound signature, because the time available and care put into XO a 2-way systems precision at their overlap think can have some influence. xrk971 thanks all the experience and sound clips shared.

 

[gmad]

Here's the impulse response to go along with the waterfall above. Measurement made with a piece of open-cell foam inside the hypercube and with the mic ~3" from the phase plug.

 

[xrk971]

Byrtt,
You have 34 of my clips in a library? LOL
I agree that I prefer the sound signature of the TC9FD better. I may be that I have too much EQ on the HF in trying to make it flatter - maybe leave it alone. That airiness has for to be the 15kHz sibilance though. One test is to put a low pass at 12kHz and see if sounds more pleasant.

 

[xrk971]

Here's the impulse response to go along with the waterfall above. Measurement made with a piece of open-cell foam inside the hypercube and with the mic ~3" from the phase plug.

I count exactly 15 peaks in 1 ms division so you have the same 15kHz sibillance - this is inherent in the driver and a signature of the aluminum "tinking" sound. I think I prefer the TC9FD paper cone sound more for lack of this signature. Thanks for sharing.

 

[sreten]

Hi,

The 15KHz prominence looks amenable to a trap filter.

One possibility not looked at much nowadays, but
introduced by Boston years ago, which also fixes
the distortion issues of such peaks, is a mechanical
trap / diffuser of some sort in front of the driver.

Diffusers, like the old style mechanical lenses,
are an interesting option in manipulating on
axis treble to off axis for beaming drivers.

rgds, sreten.

 

[BYRTT]

RS-100

ZaphAudio comment "Could be used full range with a breakup notch".
Picture is simple screen capture full details and description the 5 Star Rating System available here: Zaph|Audio.

 

[xrk971]

I lowpassed the RS100-4 with a 12kHz -36dB/oct filter and the ringing went away completely. It sounded pretty good still given that the cutoff was 12kHz. I think a 12kHz driver could be considered full range still because I wasn't missing much (to my ears).

 

[BYRTT]

Interesting outcome adding 12kHz lowpass.

Attached Dayton Audio frequency response metal verse paper version, paper adds around 5$ cost.

 

[xrk971]

I didn't know it came in a paper cone. HF seems to be less than aluminum cone but peak at 15kHz is gone.

Does anyone have impulse response of an A7.3? I wonder if ringing is present there too?

 

[gmad]

I mentioned the paper cone version in post #22. I've attached impulse responses showing eq applied to my previously shown measurement. First is of a flat response, second is with an additional first order hold lowpass (~3.5 db down at 16.3khz).