| Ropie |
| That's a big hybrid-type enclosure. What's the purpose of the panel with the four holes cut in it at the rear of the line? |
|
|
| Sjef |
I have not tried it myself but I have listened to it at Bert Doppenberg's place. The loudspeaker used was an AER MKI.
Mids and Highs were very good, very detailed and coherent. Best Highs I have ever heard from a fullrange driver, ribbon like resolution but with the guts and balls of a bigger dome tweeter. Tonal balance a little bit on the bright side but not near as bright as the typical Lowther sound. Bass output was limited in extension and power but basslines were very easy to follow. Stereo imaging was a bit on the small side (due to the lack of real low bass maybe) but very stable and precise. The sweetspot, while not huge, was much bigger than I expected. Except for the lowbass extension and capabilties it's a very nice system with no horn colouration or any noticable cabinet colouration.
They have all the goodies from a Lowther system (Dynamics, livelike sound and precise imaging) but you don't have to take ten aspirines after an hour of listening |
|
|
| Onur |
| quote: | Originally posted by Ropie
That's a big hybrid-type enclosure. What's the purpose of the panel with the four holes cut in it at the rear of the line? |
It is simply there for to distub the waves, which are reflecting from the back of the enclosure. There were much reflection from the back of the enclosure radiating to my listening room through the thin cone of AER MK1s and I've decided to reduce the magnitude of the reflected waves by placing some obstacles on their way. On the other hand, I didn't want to divide the rear chamber into two parts, since I didn't know what may be the result of such a change therefore I have drilled holes to balance the pressure on the sides. |
|
|
| jlsem |
| quote: | | It is simply there for to distub the waves, which are reflecting from the back of the enclosure. |
What is the damping material?
John |
|
|
| Onur |
| quote: | Originally posted by jlsem
What is the damping material?
|
It is one of the most important things about this TL. In theory you do not need any damping material, the enclosure handles the unwanted frequencies itself and yet you still can not sonically point your finger that you are listening to a TL design. But in real life things don't work out as they do on paper. When you need to fine tune the enclosure and when T/S parameters can not be anymore help, I prefer to use fiber which is 3 cm thick. The most important point about placing the damping material is not to fill the cross-section of the line completely. |
|
|
| maartentje |
Hai,
I am going to build the singular speaker i have orderd the speakers and i am getting working on the wood.
Greetz Maarten |
|
|
| jcake5 |
Onur,
My first post to this forum so please be kind if I am not following proper procedures for the posting of responses or the asking of questions.
I have been trying to decide on a design to follow for a new speaker system and the Singular is high on my list of designs and thank you for posting the design for the DIY community.
But I am wondering about the what I believe to be is a tuned reflex chamber that you employ behind the driver. What purpose does this chamber serve and how did you decide on volume and the tuned frequency if it is a tuned chamber?
Also, how did you decide on or calculate the cross-sectional of the transmission line?
Do you have a complete technical description that you care to share?
Lastly, can the designed be scaled for smaller Fostex drivers and if yes could you please share the methods to follow to scale the design?
Best regards,
Eric |
|
|
| noisenyc |
interesting enclosure.
funny, a conversation the day before yesterday got me thinking and reading about broadband resonators.
a certain bobby steele, late of the Misfits and the Undead was picking up a nice old PSE gibson guitar amp with a field coil speaker that i rebuilt for him and we got to talking about his stage rig.
seems his dad gave him 2 Karlson cabinets he built long long ago. dad was big into DIY hifi and ham radio.
he loaded those cabs with EVM 15' speakers and has been using them ever since. says soundmen always rave about 'em...
he loved my little fostex backhorn that i'm tweaking...and we looked up this on the web:
http://home.planet.nl/~ulfman/
verrrryy interesstinggg |
|
|
| Onur |
Hi Eric,
Sorry for my late reply but because of my email change, I couldn't be informed about the postings on this forum. I hope I am not late for this.
Although many TL designers here do not agree with me on this, I believe that the reflected waves from the bends of the transmission line enclosure rise the distortion level. On the other hand, many people try to reduce the standing waves inside the transmission line enclosure by placing absorbing materials inside the line, causing the sensitivity to drop. To get rid of those two classical setbacks of the transmission line enclosure, I have built the rear chamber with a resonator tuned to the fundamental resonance frequency of the "complete enclosure" (not just the line) . The rear chamber gives the reflected waves room to expand rather then disturbing the cone. The notch generated with the helmhotlz resonator reduces the amplitude of the first standing wave frequency inside the enclosure to the flat level. By this way you get the cleanest sound from a TL enclosure with a higher sensitivity.
As for the cross-sectional area of the transmission line, it has been optimized for AER MK1 drivers in order to receive more low bass response.
Playing with the dimensions of this enclosure can make things worse while trying to make it suitable for another driver. You can make experiments with other drivers having similar diameters to see if there is some chance of finding the heavenly sound without getting lost in the dark and cold math forest :) The enclosure is designed to work with a very small range of drivers (Low Q values) other then those driver units, the trial can be a good weekend enjoyment. By keeping the same principle, the enclosure can be re-designed for any driver unit for to take the best out of that unit.
-Onur |
|
|
| jcake5 |
Onur,
Thank you for your reply to my questions. If you could please answer one more question then I will be able to go on and start some design.
Line length - Is the back chamber length added to the total line length when calculating the fundimental frequency of the line? I think it is since the cross-sectional area of the chamber matched the line cross-sectional area but am not sure.
Line Frequency - Could you please provide the basic line frequency? Knowing the frequency will help me fully understand the equations I use to model transmission lines.
The answer to the cross-sectional area of the line was as I expected - for the driver.
Best regards,
Eric |
|
|
| noisenyc |
reading my mind, you were. thanks for that. |
|
|
| ScottG |
| quote: | Originally posted by noisenyc
reading my mind, you were. thanks for that. |
in tune with the darkside, we are.. - anytime. |
|
|
| Onur |
Line lenght is in no relation with the rear chamber dimensions, and it is only coincidence that they have the came cross-section area. They have some variables in common, they do effect each other but not in a way that you have mentioned. There are several ways of calculating the lenght of the line according to the driver unit. It can be very confusing since there are no documents about this subject. You can calculate the effective line length according to the correction method as given in Beraneks' book. You can take the center symetry line as Martin does and think that the shortest distance between the driver and the port passes through the symetry axis of the line. You may take the speaker unit or the start of the line as the referance starting point. You can use a rope and pull it between the start and the end of the line and regard its' lenght as the total line lenght (In this case you have to decide weather to take the center of the opening as the referance or one of its' corners). One of them will bring you to the same result with your simulation data, if the designer of the software has choosen the same method as you did :) Tricky ? Well, if you look at this as a hoby, it is nice, if make your living out of building TL enclosures, it must be hell !
Line frequency is simple to find. mutiply the total line length (no bends, no cross-section differences, just a simple pipe) of the pipe by 2 and divide the speed of sound with that number, it is your fundamental frequency. If there are bends, cross-section differences, rear chambers or resonators :) then you have to double click on your FEM softwares' icon :) since it will no longer be so simple to find. If you don't have any access to any of those software there are some other methods like, transfer matrix method (four pole), fem, and analytical. These are the ones you can perform by hand. In TMM (Munjal is the guy who has written the basics in his book) you simply mutiply the geometry matrices in between the source and the output, then according to the boundary conditions, which is p=0 at the open end, you find your resonance frequencies (the values which makes k=0, K=wave number), mostly used for finding transmission loss of the engine exhaust systems. In analytical method, you think that the input pressure and the output pressure are equal, also you think the same way with the volume velocities, and you generate your own analytical formulation for your specific line. There are minor differences between the methods like 1 or 1.5 Hz, so they all are dependable as far as audio is concerned.
-Onur |
|
|
| jcake5 |
Onur,
Thank you for sharing your knowledge and thoughts on the Singular. On to the drawing board for me.
Best regards,
Eric |
|
|
| hkoetz |
Dear Onur,
I have a wive:angel:. We have negotiated a maximum width of speaker cabinets in our living room of 22.5 cm (outer dimensions). Depth is not critical, heigth to a lesser extent. Now the question: can I make the cabinet smaller, without changeing the other dimensions?
Regards
Henk Koetzier |
|
|
| Onur |
| quote: | Originally posted by hkoetz
can I make the cabinet smaller, without changeing the other dimensions?
|
If you are talking about reducing the width to 22.5 cm externally then you are also reducing the cross-section area of the line, the volume of the Helmholtz resonator and the rear chamber volume. This will cause some loss in low end response of the enclosure. And the volume of the Helmholts resonator needs to be recalculated.
Which driver unit are you planning to use?
-Onur |
|
|
| hkoetz |
| quote: | | Which driver unit are you planning to use? |
Either Fostex FE207 E (would just fit) or FE167E
Henk |
|
|
| Onur |
| quote: | Originally posted by hkoetz
Either Fostex FE207 E (would just fit) or FE167E
|
I have made a quick check with those drivers and the reduced size according to your needs. The best choice seems to be FE207 E. I suspect it may need to be placed closer to the corner more then other options. Having said this, I have to say that it is not so simple with the Helmholtz resonator. You will have to cut out a large hole as given on Berts' page and tune it with your ear by reducing the size.
-Onur |
|
|
| weidok |
| quote: | Originally posted by hkoetz
Either Fostex FE207 E (would just fit) or FE167E
Henk |
Hi Henk
I have build a ml TL with the FE 167 E
and they sound wonderfull |
|
|
| hkoetz |
| quote: | | I have build a ml TL with the FE 167 E and they sound wonderfull |
This is indeed the other option I am looking into (the Bob Brines one). I have decreased the width and increased the depth accordingly |
|
|
| weidok |
I think the Fostex FE207 E 8 in is even better
more body in de bass then the FE 167 E 6 in
and i have doubled the top !!!!
depth = 375 mmm
so i made this drawing
it a little smaller |
|
|
| Onur |
I must say that you will need a little damping in the rear chamber and in the line as well, but the narrow section at the bottom can easiliy be filled with fiber, therefore you have to be careful not to cover the entire cross-section.
- Onur |
|
|
| weidok |
Thanks Onur
I always use damping behind the speakers
for reducing backlash
I am still working on this model..
I would like to increase the height to 1000 mm
the first section should be 150 mm
The narrow section at bottom
should be 125 mm
Doe we need refelectors in a tl ??
What program did you use for the simulations..
greatings Weidok |
|
|
| Onur |
| quote: | Originally posted by weidok
the first section should be 150 mm
The narrow section at bottom
should be 125 mm
Doe we need refelectors in a tl ??
|
Then you are building a TL with a "tapper ratio"<1. I must say that I am not good with TL mathematics but as far as my real life experiences are concerned this will increase the cone amplitude. If my memory doesn't fail me, I remember that your driver has a 1.5 mm Xmax. This will cause the doppler effect to be audiable even at low volumes. Another point I have to mention about your design is, avoid sudden cross-section area changes and try to keep the corss-section area the same, this will reduce the reflected waves.
As for the reflectors, the bends must be as smooth as possibe. As I always say, there is certain amount of energy reflected from the bends in a TL enclosure. In order to minimize that reflected energy and control the distorsion you have to make use of the reflectors.
| quote: | Originally posted by weidok
What program did you use for the simulations..
|
I am registered user of AJ Horn and SoundEasy. I prefer AJ horn for its' speed. On the other hand, you can see how the enclosure will perform when it is located at different places in your room, like besides a wall or at the corner. One other good feaute is, it lets' you examine the frequency response when you place the port at the back or on any parallel surface which has a offset from the speaker. This feature is very important since it lets you to control the peaks or dips in the low-midrange and upper-bass sections. AJ Horn also gives very close results to real life measurements but you have to know which real dimensions to apply as simulation parameters. It is not stated clearly inside the manual.
- Onur |
|
|
| weidok |
Here is another drawing whithout reflectors ..
I increased the height of the enclosure !!
Can you simulated this enclosure for me please ..?
And with a untapperd line 135 x 210 mm
And sumulation from the original would be handy to
I am still learning about fullrange TL 's |
|
|
| Onur |
01.jpg is the response of your final enclosure. I have also played on my design, which I have worked on before, and came up with 02.jpg (black: corner, red: floor positioning; you should be comparing your response with red).
As for the difference between them, line is shorter, the port at the back is little far away from the speaker plane, the rear chamber volume is bigger and so is the cross-sectional area. What this tells me is that this driver unit would be very happy to work in a larger enclosure because it needs the port to be at the back like 40 - 50 cm, also ~20 liters of rear chamber and larger cross-section demands such size. |
|
|
| Onur |
| The second image ... |
|
|
| weidok |
Thanks Onur
| quote: | [i]Originally posted by Onur
the port at the back is little far away from the speaker plane, the rear chamber volume is bigger and so is the cross-sectional area. |
So untapperd simulates better
will it sound better
I do not get it about the portdistance
The distance from the port to the speaker is shorter
then the original design
Did you ever used 2 resonators
In some german designs they are using 2 resonators
in a enclosure!!!
-weidok- |
|
|
| Onur |
| quote: | Originally posted by weidok
So untapperd simulates better
will it sound better |
You don't have to look for huge differences when you are examining frequency response of an enclosure. It is the minor ones which do the trick. Also, don't judge the speaker by looking at the frequency response, there are also waterfall resonse, transient response, harmonic distorsions and so on. I personally examine the frequency response for to get closer to a flat response and try to see if I expand my limits to the fullest. When it comes to sound quality, I know that I have to build the design. I have been dealing with full-range speaker enclosures for 5 years now and finnally could be able to come up with Singular :) And I have to say that anyone who is looking at the matter as a hobby should take advise from the experienced ones !
| quote: | Originally posted by weidok
I do not get it about the portdistance
The distance from the port to the speaker is shorter
then the original design |
It is the distance from the plane, where your speaker is mounted on, to the plane where your port is. In your case the distance between the front of your speaker to the rear. (boradly speaking 350, but in real life, it is not the case)
| quote: | Originally posted by weidok
Did you ever used 2 resonators |
It is like playing with an equalizer, you make the frequency response look good, but ruin the phase response. I don't like to play much with resonators for this reason. Also, if you place more then one resonators in an enclosure then you have to deal with their pass-band responses, which in many cases can do no good. I try to keep it as simple as possible. But, no, I haven't used 2 resonators in single enclosure.
- Onur |
|
|
| weidok |
thanks Onur
i am wondering how other members think about
the Singular ?
What happens be leaving the resonator out..
Can you simulate that with AJHorn ?
-weidok- |
|
|
| weidok |
This is why you will like FULLRANGE
Once you experience the full range driver you will never go back to crossovers and multi-way speakers.
Some magazine did a spectrum analysis of a piece of music many years ago and something like 85% of it is in the mid range...that being from 250 - 2K.....so unless we can get this right then what on earth is the point of extended top or pant flapping bass? The mids are the essential and crutial part of what we hear and also the area where we are most sensitive. No wonder those multiway units that has a crossover right in the middle of that range seldom sound good. |
|
|
| Onur |
| quote: | Originally posted by weidok
What happens be leaving the resonator out..
Can you simulate that with AJHorn ?
|
When it comes to resonator, SoundEasy steps in the scene. Since this is not an ordinary design, it is ver normal for simulation software not to simulate resonators. Therefore, you build the eletro-acoustic model of the resonator with SoundEasy and combine the response with the one you get from AJ-Horn. As a result, you receive the final frequency response of the enclosure.
- Onur |
|
|
| Angelm |
Hello Onur
I am waiting delivery of Fostex FE206E and i am wondering what type of enclosure to build. Searching the net i found these boxes: Singular enclosure, Folded TQWT or Fostex recommended Back Loaded Horn. The problem is my room, people build BLH says that the best bass is when put horns in the corner, but i can place speakers in middle of the wall.
My room is 5.8m/ 3.5m and the speakers have to be on the long wall and away from corners.
Could you share your experience with Singular enclosure, what is best position for them, what is the best distance from the rear wall ...
Sorry for my english.
Angel |
|
|
| Onur |
As it is the case with almost all speaker enclosures, when placed at the corners, their bass response differs from other locations. I can not comment weather it improves or not, but in some cases, it does. Your room dimensions are very much alike with my room dimensions. I am using the room lengthwise and right now, the enclosures are sitting 5 cm away from the side walls and 20 cm from the rear wall. My listening position is behind the 1/3 of the longer distance from the rear wall. I have made some modifications inside the enclosures as Bert suggested and they are playing very balanced and detailed according to my taste.
I have also tried the other way, like you have said. The bass was much more then I could have imagined. I can say that they had a better bass response when they are placed at the far corners, but again they would like to be placed closer to the corners as possible. It is hard to guess what may happen when you pull them out, since I don't know how far.
As for the other enclosures, while working on Singular, I have tried many alternatives. I have built some of them also. They all had ups and downs, but Singular has more "ups" according to my simulations. The setback is, I haven't listened to other enclosures. I have listened to enclosures that I have built with similar principles. Having said this, I have to say that, I haven't head the bass performance of Singular in neather of them.
- Onur |
|
|
| weidok |
Hello Onur
I know you are an expert on this
Would you simulate this enclosure for me please
Many thanks
-Weidok- |
|
|
|
