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Horn-Loaded Speakers
Topic: RTA and aural experiences

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Posted by Romy the Cat on 01-02-2010
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Stefano Bertoncello's posted at his blog a comment about Tony’s playback. I do not know him; I guess he is an Italian fellow or somewhere near Italy.

http://twogoodears.blogspot.com/2009/12/goto-again-visiting-my-friend-toni-and.html

It is 4-ways bi-amped playback, with multi-sell at lower MF, dual-driver ported enclosure at the bottom and two Goto above. The multi-sell is driven by Altec 288; I guess down to 400Hz. The bass is from par of Altec 416, a sort of blow up Altec 19 type of bass. The result is not overly extended very manageable, easy to use configuration.

Twogoodears, look like he liked the sound, that’s he did not described it a lot not did he described what Tony’s intended to do. But again, it is a private blog and Twogoodears is perfectly entitled to write in there whatever he wants.  Some comments:

Tony needs to move the TT from the wall a bit. The corner that TT and wall shape is a location where the pressure collects and it is right where the tonearm is.  Moring the TT for 10” ahead and creation a chenals between TT and wall would eliminate this problem.  The first order filtration and not time aligned – come on, get stereos!  I do like where the mouth of the MF Goto located. Probably I would go for a bit longer horn with lower cut off to make the horn to hang over the bass bin.  From a different perspective why Tony put the MF Goto where he put it, it is time not aligned anyhow?I do not see any means to assure that the wooden stacks that stupors Goto driver are parallel, in fact even on the picture they are not parallel. Dose Tony uses axis bending and a compensation for time miss-alignment? It would be a legitimate thing to do it he listen from fixed distance but I do not think he does.

Anyhow, what I do like in this playback is the bass section and the way how it connected with multi-sell. I am not a bit multi-sell fun but in a large room then might work more or less OK. This multi-sell can handle more bass then Altec 288 can care, I guess it would be interning to drive it down to full 250Hz with more LF capable driver if to find one. It would be interesting to use in bass bin not 416 bass drivers but the 515B or E (ferrite version of B). They have 15Hz lower resonance frequency and might yield more bass from the same box (the port would need to be retuned).

The class D amp driving the Altec 416, ehhhh!

The Cat

Posted by KLegind on 01-04-2010
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I am a big room buffoon. I like to see and hear a room and I like to walk around and "test" it. Sounds dumb but sometimes I can sit in a room and dream about what could be done to it in terms of Sound. It started around the age of 20 so at the time I really had no idea about what I was doing. Actually it wasn't that dumb and it helped me distinguish features of the room from those of the components.
Now, I could not help noticing that 2 Good Ears' mentioned the size of the room: 60 square meters. Then, look at the pic of the complete system. Lets say the speakers are 1.2 meters wide and the distance between then is the same, all in all 3.6 m. Allow for a few inches to the side walls and lets be generous and say 4 m wall to wall. This adds up to a whopping 15 meters long room (assuming its rectangular). How about those pipe resonances...? I have never experienced such a room, but it might have big problems, OR it could yield super interesting sound.

My own room is 12-13 feet wide and 21 feet long with high ceiling. First I thought there'd be big problems but its way better than any of my previous rooms. Much depends on how you manage those standing waves.

Happy New Year
Kris

Posted by Romy the Cat on 01-04-2010
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 KLegind wrote:
I am a big room buffoon. I like to see and hear a room and I like to walk around and "test" it. Sounds dumb but sometimes I can sit in a room and dream about what could be done to it in terms of Sound. It started around the age of 20 so at the time I really had no idea about what I was doing. Actually it wasn't that dumb and it helped me distinguish features of the room from those of the components.
Now, I could not help noticing that 2 Good Ears' mentioned the size of the room: 60 square meters. Then, look at the pic of the complete system. Lets say the speakers are 1.2 meters wide and the distance between then is the same, all in all 3.6 m. Allow for a few inches to the side walls and lets be generous and say 4 m wall to wall. This adds up to a whopping 15 meters long room (assuming its rectangular). How about those pipe resonances...? I have never experienced such a room, but it might have big problems, OR it could yield super interesting sound.

My own room is 12-13 feet wide and 21 feet long with high ceiling. First I thought there'd be big problems but its way better than any of my previous rooms. Much depends on how you manage those standing waves.

Happy New Year

Yes, Kris, I thought about it but decided do not comment on it and I feel it is most likely not the case. it you look at the  their picture from above, where the right channel depicted then you would see that the speaker is positioned not next to the wall that goes all the way to the end of the room but at a short wall, behind which the room continues. So, I do not think that the Toni’s system tale a full width of the room but most likely a1/2-1/2 of the width. There are other evidences that the room is not 15M long. Take a look at the second picture at the bottom – you can see carpet which is not between the speakers (center of the room) but biased to the right – it means that room most likely continues to the right. Also, on the same picture you can see a part of the table. Behind which I presume a listing location. Even assuming the wide lenses distortion it does not look too far – I would estimate 3-4M. Now, pretend that you sit 3.5 M from speakers and you room 15M, then where will you locate your records? Look at the forth picture from tope – the record shelve are located at the very end of the room, next to window.  If you are right with your estimate of 15M room length then the records are at 15M-3.5M = 11.5M away! No one would put itself into that abuse to walk over 30 feet for get another record. Not to mention that if Tony would have room length then he would move records away from window.

The second part of your question is if it possible to get any more or less civilized sound from a “corridor type” of the rooms. I generally do not like it and I prefer used wide wall of rooms. But it is very difficult to make any generalizations about it and we do not know what mode the “corridor type” room would have and how those modes would be embraced and USED by the installation. I have seen one system in a very long corridor room of 12feet wide with speakers at ridicules 25-30 feet way location. The speakers were Tannoy GRF, rectangular. To my surprise it was very balanced sound on the room. So, it is not what it is but how it being used.

The Cat

Posted by KLegind on 01-04-2010
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Yes, I missed that detail. The room seems to continue to the right... so all bets are off.

BTW. I noticed a Stereo Lab 1000Hz tractrix horn acting as support for the Goto expo. horn - kind of a pity because those Stereo Lab horn are very nicely made having a granular textured surface.

Posted by Romy the Cat on 01-04-2010
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Well, as many know I consider most of Goto users are mishugina. They might like these Goto drivers but what made then to stay with Goto hyperbolic horns is beyond me. They are HF drivers and hyperbolic has acoustic impedance jump at the end of the horn – I would never use slow-opening horns for HF channels. The Stereo Lab makes Tractrix that has mouth perpendicular to horn axis – much friendlier HF termination. LA-horn with their negative opening ever better for HF but they take more space… I never used the Stereo Lab but they look as non-expensive and no-nonsense Tractrix horns. If I experiment with Goto then I would certainly stick with fast opening profiles.

The Cat

Posted by twogoodears on 01-08-2010
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The whole room (L-shaped) is larger as you all noticed, but as Roman saw in my Blog , the listening space is smaller - i.e. about 6,5 x 4,5 meters with low 2,70 ceiling - and is a perennial work in progress... yes, the Stereo Lab 1000 hz is a true waste as a "raiser"... must agree;-)

Let me talk a little bit more about sound... I try to be not over wordy or to use hypes and the like... Toni's a friend I don't see very often, so the last time I heard his system he was still using 4 ways Onken W, 1803/2440 and TAD 2001 in a Le Dauphin, small Iwata-like horn and 2405 tweeter...

The sound was better than average, but quite shouting and definitely P.A....

My friend is mostly listening to big orchestral music of any vintage and to french light music (J. Greco, C. Aznavour and other obscure female singers I'm not aware of, most of the times recorded live à l'Olimpia)

No jazz - he hates it, nor rock...

He seems to be very partial vs. Onken W low end - which he love a lot... I'd define him as a bass freak.

Strangely, what impressed me more than low end was the upper end, better said... a smooth and true-to-life "musicality" with a beautiful, unobstrusive bass, never booming... two discs of mine: a Britten solo cello (Rostropovich) was a little larger than due or one of my Ludwig Streicher's double-bass discs was a little booming and the system wasn't imaging or hinting to any deepness in stereo scene...

... but what this system does is sounding with a nice single speaker-like sense of cohesion and a dynamically rich listening... double basses in orchestra surprise with their strokes.

That's why I described my friend sound as "event brought in the room", which is a sort-of interpretation of reality, one of the (several) truth available and tailored to Toni's taste and ears...

He seems to well understand he's down-performing with the mighty 1803... he recently ordered a Goto SG-505 mid-low driver pair and he will cut it at 220 hz. 

Believe me... this system - like my own - isn't perfect... but moving through beauty of music it sure is - i.e. the performance enter the room and the orchestra power is controlled... sure Toni settled the sense of shouting/P.A.-like sound reinforcement he listened to only a couple of years ago...

I suggested to my friend to move the mid-high and high and to toe in of some degrees the whole combo to hint to some pale imaging, but the sonic footprint is not changing... the 3,5 meters from listening sweet spot is - anyway - a great aural experience.

The merits? Goto's stuffs or Mundorf's caps x-over and a fine tuning  still in progress...  I don't know... nonetheless, the sound is VERY natural and pleasant, not rolled off or tilted to high...in a word: right... and pleasant, delicate, full of details and with performers of proper size.

I loved that listening...
    

Posted by Romy the Cat on 01-08-2010
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A few comments. I think the region that impressed you was somewhere 50Hz-500Hz, the melody range with all those fundamentals. It might appear that it was in the lower end but I think it still was the fundamentals with first overtones. Since you commented that your own playback does not do what Tony’s playback does, so you might to look into it.

I know you have a single Onken bin. You call Tony’s bass as Onken but it is not exactly accurate - it is not Onken. Anyhow, you need to determine what in Tony’s sub 500Hz sound attracted you. Do not forget that Tony’s has double driver enclosures that are 8 times larger then your, larger room and a dedicated Fundamentals Channels that sited between MF and bass – a VERY powerful tool for shape the size of the presentation.  If I were you then I would get a real time spectral analyzer (RTA) and spend a few hours in Toney room educating yourself what you are hearing. With certain experience you might not need the RTA but I do not know if you have that experience.

So, what you need to pay attention at beginning is to recognize if what you like in Tony sound comes from structure, texture or from amplitude. I can give you 99% that you were attracted to amplitude factories that would be very easy to chaise. Using RTA get reference for each individual Tony’s channels. Since he is a friend of yours, he shell let you to do it.  For left speaker, disconnect all channels except one and run 20-20K sweep. Save the result and do the same for each channel (use juts left speaker one for beginning). Then do the same sweep for all channels connected.  All measurements make with a microphone positioned in your listening spot. This would give you an idea how the individuals channels contribute in the whole sound of the Tony’s room. Then play your music and trey to roll off Tony’s bass and Tony’s Fundamentals Channel for a few dBs, paying attention what happen with your presumption of sound and correlating it with deformation of the RTA sweep. Soon on later you will be able to get the type of presentation you have in your own room – this would be an indication that it was not the structure or texture of bass that impressed you but a proper mix of amplitudes with other channels.

Go home and try to set up on your own system the similar balance patter of your Onken with the rest of your channels, This time do not listen your playback but use juts RTA sweeps. After you get the similar balance you liked at Tony’s place then listen what you got. Play within 0.5dB-1dB to fine-tune the balance. You suppose to get the similar quantitive result. You will have different sound as there is many other structural, textural, dymick and tonal differences but ONLY then your will be able to recognize the differences and some probable problems of your bass section objectively.

Anyhow, if you heard in another playback something that very much attracted you they you might want to use it as an educational opportunity to make own sound better, if you feel it worth it for you.
The caT


Posted by twogoodears on 01-08-2010
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Thanks for the wise, simple instructions, Roman, also useful to others, I believe... that's what I actually do since I - 'twas ONLY 15 months ago... - became conscious of the limits of my tuning-by-ear and got my IVIE IE-30 with Class A measurement microphone (Bruel & Kijaer) and IVIE IE-20 Pink/White Noise Generator.

That's exactly how I tuned my own system since then... one channell at a time, every single voice, first... 1 meter and sweet spot... then the other channell... then grand-total from sweet spot...

Two homeworks for next weeks: as I'll visit again Toni as soon as he'll receive his new mid-low SG-505 drivers, we'll prepare an adapter from 4 nuts Altec 1803 to screw-in Goto's and we already agreed to use my RTA gear, the very first time ever, "chez Toni's", for a diffferent way of fine-tuning the combo.

Last but (far, far...) not least... after taking pictures of IVIE's Leds reading during fine-tuning of the four ways, I'll re-handle my own speakers levels accordingly...

My gut feeling bring me to the fact Toni's keeping both high and mid-high at a lower level, so, apparently, sounding less lively than "chez moi"...

The level-of-details-scoring: my own vs. Toni's is - scale of 10 - is 7,5 vs. 6... a three ways VOT enclosure, 288 in Iwata horn and Coral H-104 would be 4,5... 

I guess it's not something related to Goto, Altec or whatever... as my sweet spot is 2,3 meters from horns nearest mouth, while at my friend place it was between 3,5 and 4 meters (must check)... the different blend of ways give a different overall result... thus the relative improved "smoothness" I noticed and appreciated, still keeping the details I'm freak of... http://twogoodears.blogspot.com/2008/03/m-u-s-i-c-amendment-and-addendum.html
and http://twogoodears.blogspot.com/2007/12/m-u-s-i-c.html

Will report asap.  
 

Posted by Romy the Cat on 01-08-2010
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The quality of microphones is irrelevant and if you use not 1/3 octave sweep but Noise Generators then you need to run time average on your RTA.  Time average analyzers is fine but it need some additional experience to interpret the results. I do not know what you call the “level-of-details” but you need to understand that Tony has very different loading number compare to you. I do not know what amp you run on bass, I seen your playback perhaps 5 years back and do not remember it well. If I am not mistaken you was running everything from the same amps. Tony’ bi-amping and for bass he use class D amps. I do not know what kind output impedance the class D amps have, I presume in the milliohms but I know that those light paper-spider vintage drivers are VERY susceptive to dumping. So, you might drive them with 4-5R vs. Tony who drive then with .05R. You can have also .05R but you will have .5W power with this impedance. The stupid class D amp would have much more or course…

Do not forget that your single bass driver on the same size room will have 1.4 times more exertion. The advantage is that your single driver bin is smaller and you can move it in search of the most optimum Imbedded Macro-Positioning

http://www.goodsoundclub.com/Forums/ShowPost.aspx?PostID=4421

The Cat


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