Mikasa, next?

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Hi Allen,

Good to hear from you. Also it's good to know that you have a healthier work schedule now. Hope this helps you maintain a better work life balance, and gives you a bit more opportunity to catch up on audio stuff. :)

Interesting update on the Avebury. Sounds like the First One 1.4M and Buffalo III DAC are a good combo, and a good match for the Avebury. You think playing around with EQ and/or damping can help you with the mid-bass?

Btw, I have an FO amp project in the works, but looks like it will take some time for me to get all the components and complete the build. Well, they say good things come to those who wait!
 
frugal-phile™
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Allen, i enjoyed your story :)

Your experience isslustrates:
1/ amps make a difference
2/ source is important, things get better as the source transmits more low level information
3/ one of the things that stand out with all the Alpairs is that they are capable of realizing low level detail

The common thread is that your system gets better if the devices in the system have higher DDR.

:)

dave
 
Stuffing???

So that brings me to the next step with Avebury: What can we do to tame the mid-bass coming out of the horns?

I remember reading in this thread a couple of years back, that doubtingthomas stuffed the thoats of his Wooden designed Fostex horn system to remove the mid-bass... ...so I thought!

Oh no, just looked it up! He initially stuffed the mouths, but then he un-stuffed them...

Memory is a bad reference!:eek::

Well... :eek::eek: ummm :eek::eek::eek:

...we can learn for the mistake I am about to tell You:

I thought he stuffed the throats to tame the mid-bass, so I tried the same thing. :eek: Thankfully, I can pull it out.

Anyway, here are the measurements.

First graph shows the comparison between a 3 inch and 3 feet distance from the driver. As You can see, a lot of "damage" already done. I would like to do a one foot measurement later to see how much of this is the cabinet baffle.

The second graph shows the output of the top horn (wanted less floor and room interaction), taken 3 inches from the back panel. The stuffing did indeed lower some of the mid-bass. It appears to have lowered the overall output also, but I do not know for sure, as the mic and cabinet might not have been in the exact positions as they where before I took the Alpairs out.

The third graph show the 3 feet axis comparisons with and without stuffing - not too different really. Again, not sure if the output drop was the set-up transition or not, but I am having a feeling it is the stuffing causing this...

The last graph shows how the speakers interact with each other. I forgot to take a listening seat measurement before stuffing the throats. Either way, You can see the 180 peak that is bothering me. The 45 Hz peak does not concern me, as I tame that with the high pass in JRiver.

But now the real question, should I be stuffing these horns at all?

It did make a difference. I do hear less room, but I am thinking I lost a little of that Alpair 12 magic too. You know how these things go.

I am thinking I need to take the stuffing out and put some absorption panels behind the horns. That would tame the mid-bass, but not the low bass, which is fine, because we want the low bass. :D

Thoughts anyone?
 

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Hope this helps you maintain a better work life balance, and gives you a bit more opportunity to catch up on audio stuff. :)

Btw, I have an FO amp project in the works, but looks like it will take some time for me to get all the components and complete the build. Well, they say good things come to those who wait!

Oh Zia, You are in for a treat! First One synergizes well with Alpair 12. In fact, I would say, it is an injustice to use Alpair 12 with anything less. And a First One build is very reasonable for the sound quality You are getting. What FO model are You building, the medium, or did You spring for the large? :D

The medium is no slough by the way. :D :D

As far as work goes, the schedule is an improvement, but I still work two jobs and run my caring business. So I am still not balanced, but I am healthier. My caring business is slowing down, now that winter is on the way, so there will be more time - at least when it does not snow. :p
 
Allen, i enjoyed your story :)

Dave, I agree with You 100%

My hope with sharing my adventure is that it IS worth it to save up and buy and build something nice. I would say First One and the Buffalo III DAC are a steal in terms of $$$ invested. The First One is comparable to my dearly missed McIntosh MC 150, for 1/3 of the cost. The Buffalo III puts me in all new territory, as I have not had the pleasure of owning a source at this level before. :D

The interesting thing, is I could still have the SAE 2100 restored for about $500 total. But for $300 more, I could build another First One! Guess what I will more then likely be doing?

I still like my Chip Amps, I would listen to those any day over an AVR. In fact i would be using them now on my back speakers if I had another Buffalo. I am limited to stereo at the moment, but with the heaps of gains I hear now, I am not suffering too badly. ;)
 
EQing

You think playing around with EQ and/or damping can help you with the mid-bass?

Glad You asked, as I want to elaborate a little.

I could EQ the mid-bass peak, but as it is caused by the room interaction with the horn and not the speaker itself, results will be less then ideal. I would get the mid-bass balanced, but it would still possess that "room sound" quality. I want to hear more of the source.

Also, I did notice, with the Buffalo DAC, I could hear "something" in the DSP processing. It was something I did not like. But I am not sure if it actually is the processing or if it was something with the arrays. I will go into greater detail on my array thread.

The only processing I have added with Avebury is a 12 dB high pass at 35 Hz. I am doing this with-in JRiver's PEQ. I would like to create a rePhase FIR for this, as the phase shift does change the impact of the bass. But the high pass does not negatively affect the rest of the sound.
 
Stuffing Photo

Here is the photo of the stuffing I added to the horn throats. I used AcoustiStuff. The piece laying on the speaker shows the size and density I used. There is not much science involved here. The main thing, is I did not want the piece to fall down the horn in case I did not like or was not supposed to do this! If I was to continue this experiment, I would stuff another piece this big down each horn throat.

but I am thinking I should be taking these out and fixing the issues with room absorption.
 

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Opps, wrong graph in post 463

The last graph is post 463 shows the my array response at the listening seat. In the case of that system, I have a mid-range loss when both speakers are playing.

Here is the graph of the Avebury. Now You can see the peaks I was referring. to.
 

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Another look at teh measurements...

Looks to be related to a dimension of ~4’ or a multiple.

You are correct, Dave, all my side walls are about 4" long, and the ceiling is a couple inches over 8 feet... So we are on the right track there.

But here is the part that has got me. I took another look at my horn mouth measurements. I did the top horn and I measured it with the horn facing in the room, away from the walls. I took the measurement 3" away from the mouth... Based on this measurement, the 165 Hz peak has already started and my room is just helping it along more (second graph).

I removed the stuffing and re-measured the system at the listening seat (first graph). As can be seen, the stuffing does not appear to help the problem (Blue and Red lines). As these measurements where indeed taken on different days with a different set-up, I am guessing that accounts for the difference in the higher ranges. The third measurement, off-set so you can see it, is the EQed version (Green). -9 dB at 165 Hz with a Q of 6, -5dB at 44 Hz with a Q of 5, and a 48dB/octave Low-pass at 25 Hz. I then correct the Low-pass phase shift with rePhase. It sounds pretty good. I would like to play around with some of the other peaks later on. At the moment, I find the sound a tad "cold", but there are a lot of other issues here also.

I would really like to get rid of the 165 Hz peak at the source, from the horn. The Alpair sounds better without the -9 dB attenuation, but without it, the room gain at 165 Hz is over whelming. Is there a way to address this peak at the source? Is there something I can do with the cabinet itself? More stuffing in the back chamber, for example? On one hand, my room might be too small for this design, but on the other hand, the fact that 25Hz is in the usable range is pretty exciting. I have not tried movies yet with this set-up, so I will get back to You later on that. :D

I am going to be experimenting with room treatments soon. I need to decide if I am getting Owens Corning 703 or Roxul 60. Shipping seems a little high on this stuff, as I am sure as many of You has found out, most hardware stores do not carry this stuff.
 

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Another look...

I was reviewing my post above, and looked at the first graph. The mids and highs are much more rolled off, so I off-set the measurement to make them more even. Did the stuffing attenuate the horn that much? It did not change the frequency response, but it did attenuate, maybe. Might be time to get the making tape out.

Thoughts anyone?
 

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