GoodSoundClub - Romy the Cat's Audio Site

10-19-2015

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Romy the Cat

Boston, MA
Posts 10,155
Joined on 05-28-2004

Post #:	21
Post ID:	22117
Reply to:	22116

Since you are in planning phase...

kodomo, there is a thing that you need to understand. The objective to have bass channels outside is valid but it is applied to a perfect condition when you have unlimited width. In the situation like you’re the objective to have bass channels outside might not be beneficial. You see, by letting the bass sources to sit outside and gaining on imaging we narrowing the horns closer to each other and losing in imaging. It is not even the “losing in imaging”. There is a very intricate dependency between listening distance, max width between the channels, the room treatment, the room size, the speaker topology, the type of tweeter mounting, the crossovers, the integration methods and etc…. I can name another 30 dependencies. The present of bass outside in your situation is no matter what but it will set the horns out of max width your installation can handle - In my mind it is always best to have max with possible without distraction of a center image.

So, what I post my criticism about this or that aspect of somebody installation them it is not imperative that something in my mind need to be changed but rather the direction that the system owner might find useful to explore. If I own your playback and someday told me that bass channels inside is no good then I would make an experiment with it and then make my own judgment how important would it be to me and how much I am willing to sacrifice in other aspects of my life, including the living comfort. So, do your own experiment with bass in and out, with horns wider and narrowing. Ultimately it is your playback and your decision what you will be doing. As I told to Murataltuev a few days back – do not harry. Make an experiment and let it to grow on you. Get use to results and learn to distinct “better” from “different”.

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

11-11-2015

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kodomo
Posts 69
Joined on 06-20-2015

Post #:	23
Post ID:	22225
Reply to:	22091

Second filter on upper bass! thanks

I have tried a second filter on the Supravox as per your suggestion. Very interesting, it really has audible effect on the sound even if it is small when I put the filter around 40hz. I will try on 60hz and 80hz and keep on listening. It will take time for me to assess this new information as I will need to keep on listening. Just wanted to thank you. I am planning to experiment with the fundamentals channel the same way as well.

Oh and the fundamentals channel although begging me to play a wider range, more or less disappears and actually helps the sound to have more volume (not loudness) when covering a narrower range. It sounds like I will cover just an octave it and its height won't be a problem like I thought it might. I sit about 14 feet away from the mouth of the upperbass horn.I am planning to get a foster r100t attenuator for my fundamental channel. I think it can help me to adjust my system better and can vary in its attenuation depending on my listening distance.

So far I am liking the Radians, but time will tell. First few months impression is it doesn't sound as edgy as my BMS 4592nd-mid 16ohms but seems to have the detail with a more relaxed presentation. Are BMS 4592nd-mids more dynamic or too dynamic I haven't assessed yet.

11-11-2015

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Romy the Cat

Boston, MA
Posts 10,155
Joined on 05-28-2004

Post #:	24
Post ID:	22226
Reply to:	22225

A driver for fundamentals channel.

kodomo wrote:
Oh and the fundamentals channel although begging me to play a wider range, more or less disappears and actually helps the sound to have more volume (not loudness) when covering a narrower range. It sounds like I will cover just an octave it and its height won't be a problem like I thought it might. I sit about 14 feet away from the mouth of the upperbass horn.I am planning to get a foster r100t attenuator for my fundamental channel. I think it can help me to adjust my system better and can vary in its attenuation depending on my listening distance.

So far I am liking the Radians, but time will tell. First few months impression is it doesn't sound as edgy as my BMS 4592nd-mid 16ohms but seems to have the detail with a more relaxed presentation. Are BMS 4592nd-mids more dynamic or too dynamic I haven't assessed yet.

The foster attenuator if fine for fundamentals. It is very inductive and will eat all your HF but you do not need them anyhow. The selection of driver for fundamental channel is a bit tricky. I find that you do not need a good driver but rather a driver that would go a very few thing in a very specific way. The fundamentals driver is a viola driver, it do not need to have the violin finger work but in the same time it should not have a rich viola tone. it is kind of contra intuitive - you almost want to have a bad driver in there. The problem is that in one octave in lower MF and relatively sharp filtration the channel will not develop "tone". So, I would not go for tone but rather for texture. I find that if you get an atrocious driver and they make it even more evil by idle it load then it might be a good candidate for fundamentals. Of couse everything in moderation and you need to make it to work with your MF and upper bass. Still, the fundamental driver is kind of filling the gap driver and it more gives "sonic fog" then sound. I would like this "fog" has some tension, some kind of over rosined bow effect with a lot of "bite". Tone, it is what my MF driver does. the fundamentals just gives to MF a bit agitation at the bottom of MF.

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

11-22-2015

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kodomo
Posts 69
Joined on 06-20-2015

Post #:	25
Post ID:	22240
Reply to:	22226

New frame and crossover experiments

While I am waiting for the attenuators I worked on the frame and changed it to a metal frame.

It is sturdy and height of the channels can be adjusted in both axis.

Romy, may I learn what your crossover points for your channels?

My midrange channel is begging me to cover between 640 to 3800 with a 6db crossover 1200 and 2000 respectively. It blends well with the jmlc1000, which covers up to 7400. I was expecting higher, but I just started playing around with it.

So for starters it looks like this now:
160-640 upperbass with supravox 285-2000 hornfabrik edition with 110hz tractrix
640-3800 midrange with Radian 850pb and 200hz tractrix
3800-7400 upper midrange with Radian 475be-pb and 1000hz jmlc
7400-20000 treble with Fostex t500amkII

Upperbass channel easily covers 160-640. I haven't yet finished the direct radiators. Its parts are cut, the drivers are here but I need to get it together and paint.

11-22-2015

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Romy the Cat

Boston, MA
Posts 10,155
Joined on 05-28-2004

Post #:	26
Post ID:	22242
Reply to:	22240

A few comments.

I very much like a few things you did with the frame. I like that the stack is compact with no wasted space. I like that you have the highs of your frame higher then you need as if you go for slightly larger MF channel then you have a frame height to accommodate it. I like that you reversed the MF and tweeter. It is not a configuration that I would like generally but in context of your drivers it is a very proper move and it clear indication that you properly react upon what you are hearing. I love that the frame has those whole that allow to hung the channels at different heights. It is perhaps a bit utilitarian but inexpensive and a very effective solution.

A few comment what I do not like. The rollers at the bottom. They add 2-3 inch to the elevation of the horns and they make the frame less stable on the floor. In case you have a hardwood floor I very much advocate to use felt feet. Any home improvement store has zillion of them, juts self-adherent felt pads and they work wonderful. You still will be able to move the horn across the floor.

Regarding your questions. My crossover points should not be relevant to you as it has to do with my horns, my driver and a few other things. I am not the person who believe that a crossover point shall or shall not be in this or in that range - it might be anywhere you drivers and a few other thing would make it to be. So, where I cross the channels is irrelevant unless you do the direct Macondo replica, something that you shall not be doing anywhere...

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

11-22-2015

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kodomo
Posts 69
Joined on 06-20-2015

Post #:	27
Post ID:	22243
Reply to:	22242

Crossover relevancy

Yes, I do believe your exact crossover points would be irrelevant as well. I just wanted to know the span of your horns and drivers. I especially wondered about your fundamentals channel. You said it was narrow but what is narrow for you. Mine covers about 2 and a half octaves and with very important information. So that is why I stopped calling it fundamentals channel and just called it midrange. The effect I get is not similar to what you describe (if i could understand it right). It does not just add texture but also contains the tone but not the whole of the tone. The instruments body is not there, but the rest is quite there. It is like the anchor of the system. The strings without it does not just miss the texture but also the timbral uniqueness...

The position of the horns are dictated by the design, I had to put them in this order according to what I hear.

It is very convenient for now to keep the wheels. I am thinking of a solution, with shallower feet that are fixed. When I take off the wheels, they can stand on them. When I want to move, I can just insert the wheels back. These are trivial at this point but I always keep on thinking.

11-22-2015

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Romy the Cat

Boston, MA
Posts 10,155
Joined on 05-28-2004

Post #:	28
Post ID:	22248
Reply to:	22243

How narrow is narrow...

Yes, what you describe completely makes sense. In your case the upper horn is not what in my systems. Since you have no truly MF channel but rather upper MF and HF your Fundamental is kind of main source of sound. My Fundamentals covers from around 600 to 1000 and (if I am not mistaken) and has a very sharp filter at upper knee (third order).

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

01-22-2016

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kodomo
Posts 69
Joined on 06-20-2015

Post #:	29
Post ID:	22406
Reply to:	21722

An update and some more ideas

I have been working on my system. I post sparse as I need to listen a lot before doing any changes or decide on anything.

I have changed the 1000hz JMLC horn to a 1400hz JMLC horn and the results are better. I have better integration with the Fostex t500amkII and the crossover point of the fostex t500amkII's are now a little higher. This means better efficiency and less reflections from the top of the upperbass horn for me.

I have also been working on crossovers and it seems when you have 6db filters, for them to be effectively working the impedance response should be as flat as possible. Then they work accordingly. So the simple 6db filter is not so simple at all. Now I understood why these Vandersteen crossovers look like they do!

My channels are now working in between these frequencies effectively;
Dual TAD 1601b bass reflex boxes: 34hz to 150hz
Supravox 285 in 110hz tractrix: 150hz to 500hz
Radian 850 in 200hz tractrix: 500hz to 4500hz
Radian 475be in 1400hz JMLC: 4500hz to 9000hz
Fostex t500amkII: 9000hz to as much as they can play up to Smile

I had been demolishing walls etc, so there is a lot of dust around and the horns look filthy. I will be posting beau photos in the coming month, with the whole system.

My cat enjoying the measurements Smile

03-07-2016

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kodomo
Posts 69
Joined on 06-20-2015

Post #:	30
Post ID:	22557
Reply to:	22406

Nearly there!

I have my passive crossovers arrived. They are built by hornFabrik. Everything is up to the spec I asked for and I really like their build quality. As of yesterday, I have now a more promising sound towards what I have aimed for. They are first order built specifically for my drivers and their responses after me measuring the hell out of them. The result was worth my time and the cost is justifiable for me.

The main horn system has small relative attenuation work which I can easily do as the crossovers boards are designed to accommodate changing resistor on r1 and r2 very easy. I also have the fostex autoformer on the 200 hz horn.

The main thing to work on will the integration of the dual Tad bass units to the room. They will be on the outside like this but their perfect position and the panels I built to work with them has not yet been implemented. As usual I am going slow, and will be testing them in a lot of different positions and listen to them enough to have an honest opinion.

Here is the first day setup after crossovers with everything in order (except the room is not yet finished).

03-09-2016

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Romy the Cat

Boston, MA
Posts 10,155
Joined on 05-28-2004

Post #:	31
Post ID:	22561
Reply to:	22557

What a crossover!

That is a fancy one, with vacuum caps as I can see it. I do not know about the practicality of vacuum caps – they have own pluses and minuses. Still, that is nice crossover, a bit more complicated then I initially thought I has to be. It would be nice to see a schematics…

The picture of the room is nice. How does it sound? Among the things I would do would be pile up two or 4 more driver per channel in LF section. They should create more array like cylindrical wave (will help with room more a lot in your short wall configuration). I would also put some kind of window treatment over that large glass surface behind the speakers.

Rgs, Romy the Cat

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

03-09-2016

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kodomo
Posts 69
Joined on 06-20-2015

Post #:	32
Post ID:	22562
Reply to:	22561

Vacuum caps and more

Yes, the crossover looks fancy Smile

More than that it does the job. The vacuum caps are only for the tweeter and the upper-mid beryllium. Still they are bridged with micas as they wont do much alone. Adding vacuum caps smoothens the transitions and sounds very neutral while doing it, at least to my ears.

The room is not yet integrated with the speakers. I am positioning them (thanks to the wheels) and the acoustic panels, then listening for some time. It looks like it would take months for me to be really satisfied with the setting up. This is no problem though, this is the case with such a complex system. The glass windows disappear when I press a button and my cinema screen comes down. It is not acoustically transparent, so it subdues the glass reflections...

What I can say for the sound. I can say this is a subject I don't like! Still I can say, there are not many problems with the horns. I have aligned them yesterday more precisely and they integrated better. As I am about 470 centimeters away from them, alignment is not a big issue. 200 hz horn is about 3,3cm closer to than the fostex, the 475 is about 0,2 and the bass horn about 5,92cm closer.

I took the 200hz horn 5 centimeters higher and it really helped with the reflections of 1400 hz jmlc. I found out, every driver needs a bit more space than I assumed. So the system is now about 13 centimeters higher. When I cut the wheels out after I am happy with their positions in the room, it will bring it down 8 centimeters. Overall height will be close to my first approximation with the drivers being more apart.

It seems I will have to fix some feet to the bass units, they do not like to sit on the carpet. It makes them a little sluggish. I have some at hand, so I plan to do it on weekend.

Also the back chamber of the basshorn can take more filling it seems, this is on my weekend to do list as well...

I also tried my tapped horn working below the bass units, from about 20 hz to 40-50 hz and it integrated better than I expected. I may continue to use it. Strauss convinced me at the beginning of the piece "Also sprach Zarathustra" with that sustained low C on the organ Smile

03-11-2016

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anthony
Posts 338
Joined on 08-18-2014

Post #:	33
Post ID:	22563
Reply to:	22562

The height...

kodomo wrote:

I took the 200hz horn 5 centimeters higher and it really helped with the reflections of 1400 hz jmlc. I found out, every driver needs a bit more space than I assumed. So the system is now about 13 centimeters higher. When I cut the wheels out after I am happy with their positions in the room, it will bring it down 8 centimeters. Overall height will be close to my first approximation with the drivers being more apart.

I was wondering about this in context of my own frame. Your experience has now cemented for me that I should have the option with my frame to alter the height of the individual channels. Thanks for sharing your experience, and I really like your room and your obvious dedication to your audio project.

03-11-2016

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kodomo
Posts 69
Joined on 06-20-2015

Post #:	34
Post ID:	22564
Reply to:	22563

Height and some more info

Hello Anthony
Do not worry too much about how high the system ends up or how high the highest horn is positioned. If you are far enough (I am 470cm away from my drivers) and align them properly, the sound is right in front of you. Actually my system is about 2meters high but the soundstage is lower than my old modified klipschorns!
If anyone is wondering about the initial system response, here is an spl graphic.

You can see the two main problems being 70hz and 200hz in this graph. 200hz is from the floor bounce of the basshorn. I will add absorbers to the floor. The 70hz peak is from the Tad bass units sidewall reflection. That area will also be treated with acoustic absorbers.

03-11-2016

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anthony
Posts 338
Joined on 08-18-2014

Post #:	35
Post ID:	22565
Reply to:	22564

Floor bounce...

kodomo wrote:
Hello Anthony

You can see the two main problems being 70hz and 200hz in this graph. 200hz is from the floor bounce of the basshorn. I will add absorbers to the floor. The 70hz peak is from the Tad bass units sidewall reflection. That area will also be treated with acoustic absorbers.

Kodomo, I have not looked back through the thread to see what your horns are made from (they look great by the way!), but have you put an accelerometer on your horns and measured their resonating frequencies? Ever since I put my hands on a circa 110Hz fibreglass horn and felt it shaking I wondered how much "noise" in dB it was making of its own which is why I have made my UB horn so massively heavy from MDF...even the backchamber is enormously thick to counter the vibrations from the back of the driver. I am not ready to measure this myself, and I don't really know just how much it could contribute to the frequency response, but I find it interesting nonetheless.

If you feel it is worth looking into, perhaps try adding some temporary mass or damping to the outside of the UB horn and remeasuring the frequency response to see if any dips or bumps move at all (remember to do the before measurement with the microphone in exactly the same position). Or if you have an accelerometer, give that a go. I would be most interested in what you find...but your horn may well be adequately damped and you will find nothing at all.
Cheers,
Anthony

03-11-2016

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Romy the Cat

Boston, MA
Posts 10,155
Joined on 05-28-2004

Post #:	36
Post ID:	22566
Reply to:	22564

A few comments....

Kodomo, be advised that if you move your individual drivers up and down then you need to do time realignment of your systems.

You finding about the “drivers need some space” is kind of controversial. Let me to talk a little bit about the subjects. My experiments with the Macondo topology suggested that the dependency to space for individual divers to a great degree depending from the proximity of the entire speaker to boundaries. For instance if a speaker is located close to the side or back wall (back was is more critical) then you can feel very well the vertical position of the drivers. It is not that more space is good or less space is good but rather you do feel impact of moving drivers up and down. IF however a speaker is well acoustically detached from the walls (let say it is 6-8 feet to the horns with diffusers on the walls) then musing the driver up and down impact sound less. You still will have impact in driver integration but it will be rather “equally good” then “one better than other”.

A few words about your frequencies response. You have slightly shallow response under 70Hz. That little peaks that you have at 70Hz masked it out but it is there. With response like this you will not be able to get luxury slow bass, you will not have proper “space” and your MF will have no lower harmonics support. Take some crappy $50 subwoofer, set it in phase with 35Hz line up the LF to be 2-3dB over the MF. Get the impact it make to the overall sound. Now, get rid that crappy subwoofer and try to get the same response only by more honorable means….

Rgs, Romy the CaT

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

03-12-2016

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kodomo
Posts 69
Joined on 06-20-2015

Post #:	37
Post ID:	22567
Reply to:	22566

Alignment and tapped horn as my sub

Yes, when I move the drivers or for that matter if I move my listening position, I realign.

What I hear and measure about the drivers relative distances to each other is this. When I first set up the drivers, one horn ended and the next one started, there were no space in between. Actually unless I sit at 120cm high (ear height), the tweeter was below the bass horns relative to the listener. So at the end, I took the tweeter 10cm higher. Then kept the distance between tweeter and upper mid, it is ok for one to end and the other to start. I had moved my 200hz tractrix 5 cms higher and that helped the 1400jmlc and did not hurt or effect the 200hz tractrix. After doing this many small dips and small inflations in the sound pressure were gone.

This SPL graph is without me turning on the tapped horn. I can do what you say already. I can understand what you mean by space, because since I built my tapped horn and did not compromise and built it full size, I can hear and feel that "space"

03-14-2016

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kodomo
Posts 69
Joined on 06-20-2015

Post #:	39
Post ID:	22569
Reply to:	22566

With the tapped horn

It goes quite flat to 20hz with the tapped horn. 20hz to 60hz with the tapped. It has 18db/octave Linkwitz-Riley, and then to dual Tad1601b, where you see the rising of the response around 74hz. I have tamed these bump some, but it needs a little more work. When the system goes fown to 20hz like this, the whole representation becomes something else. Its like having a transparent spatial cushion underneath for the rest of the soundscpae to float on...

07-27-2016

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kodomo
Posts 69
Joined on 06-20-2015

Post #:	40
Post ID:	22688
Reply to:	21722

The latest measurement and small changes

Maybe, some people would be interested in what I am doing with my system. I have been continuously listening and sparsely making changes and letting them sink in. For now, I feel more settled and think the biggest obstacle for me in reaching the sound that I dream is primarily about the listening space. It is not bad but it is not the best suited one for my system. Space has the most potential for improvement.

I have reduced the internal volume of the back chamber of my upperbass horn with very thick and strong felt.

I have been trying different relative attenuations on my channels, and now it has been set for over a month.

I have taken down the tapped horns 18db/oct crossover from 60hz to 30hz. This and the back chamber really taken bass to an even better experience.

Next thing I am going to do is, cover internals of the whole woofer boxes (except for the baffle) with felt lining. Although I can not hear any, I still I think it will be better as it is a vented box and higher frequencies may be bleeding through ports, it will also be good for lowering THD... By the way, the TAD TD-1601b's sound quite wonderful after some burn in. If I did not have the upperbass horn, they would easily match with the 200hz tractrix! Still the biggest improvement I had was the upperbass horn so it is not going anywhere.

Here is the latest SPL response from my listening spot. I am about 530cm away from acoustic centres of my speakers. If I move the mic closer to tweeter height, the treble extends and that bum around 10khz tames. I sit a little lower than tweeters, and I will fix that. This measurement is exactly from where my head is. You can see the rooms effects below 200hz, this will be solved by a new room...

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