Back to building OB

[Subbu68]

Had been off the network for quite some time. The itch to build my proper OB with Lii F6 always lingered in my mind. Had bought a jigsaw almost 2 years ago. But not the wood. Can I do it or not with my limited carpentry experience was the question. And in the apartment how to manage?

My wife and daughter were after me to throw out the cardboard baffles I had made for Lii F6.

Finally over the last month or so, worked out the baffle on Basta and concluded at a baffle width of 655mm OR 705mm and driver at height 675mm off centered at 250mm from the inner edge.

Picked up courage and went to a DIY store here in Abu Dhabi (ACE Hardware). They had a 801mm x 405mm x 18mm cut MDF. That limited the "perceived width" of the OB to 405mm. Baffle could be widened by adding wings. Started off with it.

The first attempt with cutting the hole for the driver went way offfff.. inverted the board to cut it neat next time. The other board came out fine. That was the first attempt at using the jigsaw.

The sound with this baffle was just fine. Without the KEF Kube it sounded like a 80's tape recorder.

Now to make the wings. consultations were on with @yogibear

Now that conclusion of 655mm or 705mm was based on the offset being 250mm from Y axis. 810mm wide baffle was getting "bumpy". If the wings were on both sides, the offset could be tailored adjusting the wing widths for a smoother 810mm

Made a simulation on Basta for a 810mm baffle. Basta said 480mm offset from outer edge (left edge of Left speaker in the picture) is optimum. (the green curve but legend is wrong)


I could possibly get the MDF cut to two pieces of required width if I got the same 405mm wide board. ACE obliged and got it cut as 325mm and 80mm. And just fitted them to one speaker for now.


Speaker wire is 2.5m of Kabel Direct 2.5sq.mm and soldered direct to the speaker terminated with KD banana plug on amp side. Wire is an overkill but that's what I have in stock.


More work to be done... R speaker to be assembled with the wings, primer and paint.

Need I add the L brackets that were supporting when it was only a flat board? @yogibear and other OB builders

 

[yogibear]

Quite nice for the first attempt however does it alter the simulation if you flip the side baffles ?

It’s kind of defeats the off centering purpose when you use deeper L on the smaller edge side of the front baffle.

I always centered the driver on the front baffle and attached a deep side baffle only on one side, towards the side wall.

For an example, excellent OB build by GR Research :

 

[Subbu68]

Quite nice for the first attempt however does it alter the simulation if you flip the side baffles ?

It’s kind of defeats the off centering purpose when you use deeper L on the smaller edge side of the front baffle.

I always centered the driver on the front baffle and attached a deep side baffle only on one side, towards the side wall.

With this configuration it comes to 480mm offset from Y axis of Basta. Measurement is not very clear but you can see that offset on the screenshot with the Baffle Designer tool in my post.

If I flipped the wings and made this unit the R channel, the offset from left edge of Basta (edge towards wall - I have no nearby wall) becomes 575mm and FR like some roads in monsoon. Deep valleys and humps.

I am just playing some songs - carnatic fusion. The left with the full set of wings is much more full than the flat board

 

[Subbu68]

@yogibear Samir

Here's the comparison of switching wings. Red is the 480mm offset (what I did) and blue is the switched wing. I believe, I have to add a good amount of BSC to make it flatter with switched wings. Any comments?

 

[Hari Iyer]

Nice attempt. You shall be surprised when you measure your OB vs simulations. The Basta does not consider dipole peak and dipole roll-off below the baffle step in free space mounting correctly. Nevertheless you can measure and add compensation network.

I abandon my ob mids/ highs 2 months ago as my room was too small for an OB to breath. This caused compression of mids without a diffuser on the front wall. Will be curious to see measured results.

 

[Subbu68]

Nice attempt. You shall be surprised when you measure your OB vs simulations. The Basta does not consider dipole peak and dipole roll-off below the baffle step in free space mounting correctly. Nevertheless you can measure and add compensation network.

I abandon my ob mids/ highs 2 months ago as my room was too small for an OB to breath. This caused compression of mids without a diffuser on the front wall. Will be curious to see measured results.

Since I don't do this frequently (in fact started DIY with OB only after joining HFV) I haven't invested in a measurement jig. All I have is a recording mic from BOYA that my wife uses for her music recording. Would that work with REW?

My room has good space. The nearest wall (glass window panel) to the left of the speaker is some good 2.5m away and with curtains. The other side is some 4m from the right channel.

 

[Subbu68]

@yogibear Samir

Here's the comparison of switching wings. Red is the 480mm offset (what I did) and blue is the switched wing. I believe, I have to add a good amount of BSC to make it flatter with switched wings. Any comments?

@yogibear My bad Samir, I could have cut the deeper wing 230mm wide and attached to the edge far from the driver (250mm offset side) to get the same offset of 480mm. And the other portion of the 405mm wide MDF (175mm) to go to the other edge to get what you commented.

But then with nearly comparable size of wings, won't it form a sort of a cavity?

Before I clip that wing

 

[Hari Iyer]

Since I don't do this frequently (in fact started DIY with OB only after joining HFV) I haven't invested in a measurement jig. All I have is a recording mic from BOYA that my wife uses for her music recording. Would that work with REW?

My room has good space. The nearest wall (glass window panel) to the left of the speaker is some good 2.5m away and with curtains. The other side is some 4m from the right channel.

Not sure about Boya microphone. But the dipole peaks and baffle roll-off sre below 300hz mostly and for your baffle size will be around 200hz which most mics could measure. Btw, do you have a calibration file for the Boya mic? If yes, then it can be used with REW.

 

[Subbu68]

Not sure about Boya microphone. But the dipole peaks and baffle roll-off sre below 300hz mostly and for your baffle size will be around 200hz which most mics could measure. Btw, do you have a calibration file for the Boya mic? If yes, then it can be used with REW.

I don't have any calibration file for it. It is meant for mini studios.

 

[yogibear]

@yogibear My bad Samir, I could have cut the deeper wing 230mm wide and attached to the edge far from the driver (250mm offset side) to get the same offset of 480mm. And the other portion of the 405mm wide MDF (175mm) to go to the other edge to get what you commented.

But then with nearly comparable size of wings, won't it form a sort of a cavity?

Before I clip that wing

Don’t read too much in Basta simulations, take it as a rough guide. Since it’s your first attempt, use those L shape steel connectors to hold the side baffles to attach to the front baffle. Experiment and listen to the variations. With one particular setup (irrespective of the absence of side walls), you will have full bodied vocals and good HF and LF extension. Settle with that.

BSC is inapplicable to OBs as it’s a dipole execution.

Though it’s quite rewarding particularly with single capable FR in OB plus Tubes, at one point of your time, you would want to execute a multi-way OB setup. I can suggest an excellent build when you are ready.

All this, only when you have large space else OB is no good. You do seem to have a large space. Enjoy your build !

OB converts music lovers into DIYers and gradually into accomplished / learned ones. Many of my friends are real life examples, now into serious builds all by themselves.

Though the Lii Audio F6 is indeed a little Devil but large 12-15” single FR OBs are the final way to do it. There you get compensated for the need of good low end, easily extending down to 50hz. The Fane 12” and 15” are the best VFM for the job. Team that with a nice SE tube amp, and you can live with it for life.

 

[Subbu68]

Don’t read too much in Basta simulations, take it as a rough guide. Since it’s your first attempt, use those L shape steel connectors to hold the side baffles to attach to the front baffle. Experiment and listen to the variations. With one particular setup (irrespective of the absence of side walls), you will have full bodied vocals and good HF and LF extension. Settle with that.

BSC is inapplicable to OBs as it’s a dipole execution.

Though it’s quite rewarding particularly with single capable FR in OB plus Tubes, at one point of your time, you would want to execute a multi-way OB setup. I can suggest an excellent build when you are ready.

All this, only when you have large space else OB is no good. You do seem to have a large space. Enjoy your build !

OB converts music lovers into DIYers and gradually into accomplished / learned ones. Many of my friends are real life examples, now into serious builds all by themselves.

Though the Lii Audio F6 is indeed a little Devil but large 12-15” single FR OBs are the final way to do it. There you get compensated for the need of good low end, easily extending down to 50hz. The Fane 12” and 15” are the best VFM for the job. Team that with a nice SE tube amp, and you can live with it for life.

@yogibear Thank you for the encouraging words.

I am just now listening to Danny Richie of GR-Research as you suggested and his part-3 video. It is an experiment and experience I'd say than reading some reviews and picking a speaker from the shop.

In Danny's video his drivers are mounted on narrow baffles and centered and he plays with the wings to create the offset. In my case I had started with an off centered hole cut thinking of ending up with a L shaped baffle with the total width of 655mm but further experimentation with 810mm width ended up with the one I built now.

I have a couple of 3mm cardboard with the same height as the front that I can use to experiment the wings or get some foam board from the hypermarket next door.

All this started with the itch to get away from multiway box speakers.

 

[arunkvivek]

Lovely build!

 

[sunder]

Had been off the network for quite some time. The itch to build my proper OB with Lii F6 always lingered in my mind. Had bought a jigsaw almost 2 years ago. But not the wood. Can I do it or not with my limited carpentry experience was the question. And in the apartment how to manage?

My wife and daughter were after me to throw out the cardboard baffles I had made for Lii F6.

Finally over the last month or so, worked out the baffle on Basta and concluded at a baffle width of 655mm OR 705mm and driver at height 675mm off centered at 250mm from the inner edge.

Picked up courage and went to a DIY store here in Abu Dhabi (ACE Hardware). They had a 801mm x 405mm x 18mm cut MDF. That limited the "perceived width" of the OB to 405mm. Baffle could be widened by adding wings. Started off with it.
View attachment 88181
The first attempt with cutting the hole for the driver went way offfff.. inverted the board to cut it neat next time. The other board came out fine. That was the first attempt at using the jigsaw.

The sound with this baffle was just fine. Without the KEF Kube it sounded like a 80's tape recorder.

Now to make the wings. consultations were on with @yogibear

Now that conclusion of 655mm or 705mm was based on the offset being 250mm from Y axis. 810mm wide baffle was getting "bumpy". If the wings were on both sides, the offset could be tailored adjusting the wing widths for a smoother 810mm

Made a simulation on Basta for a 810mm baffle. Basta said 480mm offset from outer edge (left edge of Left speaker in the picture) is optimum. (the green curve but legend is wrong)

View attachment 88182
I could possibly get the MDF cut to two pieces of required width if I got the same 405mm wide board. ACE obliged and got it cut as 325mm and 80mm. And just fitted them to one speaker for now.

View attachment 88183View attachment 88184
Speaker wire is 2.5m of Kabel Direct 2.5sq.mm and soldered direct to the speaker terminated with KD banana plug on amp side. Wire is an overkill but that's what I have in stock.


More work to be done... R speaker to be assembled with the wings, primer and paint.

Need I add the L brackets that were supporting when it was only a flat board? @yogibear and other OB builders

What a neat & clean listening area! I appreciate you. I could see that there is no any carpet on the tiled floor and the room has glass partition wall, then how you manage the sound reflection? Are the Klipsch speakers suitable for a room without any soundproofing? Thanks.

 

[Subbu68]

What a neat & clean listening area! I appreciate you. I could see that there is no any carpet on the tiled floor and the room has glass partition wall, then how you manage the sound reflection? Are the Klipsch speakers suitable for a room without any soundproofing? Thanks.

Thank you for the compliment.
It is our living room where we 'live". Nothing as a special listening area.

A joint effort to keep it neat and the clean looks

The glass is the outer wall of our room 4m wide and 3m high. Normally I listen to music in the evening when we draw the curtains.

Carpet is a big no as it accumulates a lot of dust on it and under it. So not allowed. We have couple of sofas facing the speakers and they are fabric covered and cushions.

The sofas and curtains must be absorbing the sound. I have not attempted to replicate the room treatment lessons and make it look like a lab. Just listening in an average Indian home.

Klipsch shows no issues for me.

Or I am not aware how bad or good is our living room.

 

[sunder]

Thank you for the compliment.
It is our living room where we 'live". Nothing as a special listening area.

A joint effort to keep it neat and the clean looks

The glass is the outer wall of our room 4m wide and 3m high. Normally I listen to music in the evening when we draw the curtains.

Carpet is a big no as it accumulates a lot of dust on it and under it. So not allowed. We have couple of sofas facing the speakers and they are fabric covered and cushions.

The sofas and curtains must be absorbing the sound. I have not attempted to replicate the room treatment lessons and make it look like a lab. Just listening in an average Indian home.

Klipsch shows no issues for me.

Or I am not aware how bad or good is our living room.

Yes Sir, you are right that carpets accumulate dust and we need to put much effort to be dust free. Sir, do you listen radio on Short wave bands? Most of the SW radio broadcastings were permanently stopped. Even though plenty of FM staions available, I miss the thrill of capturing stations on SW bands. If it's possible , please let me know the SW band frequencies for Tamil & Hindi (for Bolywood film songs). I am trying to use my vintage Philips valve radio. I hope that you are getting SW effortlessly on your Grundig transistor radio. Thank you.

 

[Hari Iyer]

BSC is inapplicable to OBs as it’s a dipole execution.

.Though the Lii Audio F6 is indeed a little Devil but large 12-15”

Below the baffle step, the OBs roll-off at the rate of -6db/ocatave and needs to be compensated with a low-pass shelving. You would not need a baffle step compensator but a low-pass shelving compensator to address this issue. Also there will be a dipole peak which is as high as 12dB at the calculated / measured value which will require a notch at this frequency for a flat frequency response.

There are some negative reviews about the Lii Audio 12" and 15" in YT. I am not sure whether i should take them with a pinch of salt. But there are lots of measurements in this video given as evidence, though we could not independently confirm that. Should exercise some caution here too as the cost of the drivers are too high to risk purchase.

 

[Subbu68]

Now both channels are with the full wings. The listening is indeed a bliss. Speakers are about 2.5m apart and image is dead center. Lionel Richie in Dancing on the Ceiling is all around the room walking. Drumkits play at the back while he is in the front. Another Indian CD the announcer in a live concert is in the room.

What would be then the listening with high end OBs or those from Hari, Samir and other veterans in HFV

 

[yogibear]

Now both channels are with the full wings. The listening is indeed a bliss. Speakers are about 2.5m apart and image is dead center. Lionel Richie in Dancing on the Ceiling is all around the room walking. Drumkits play at the back while he is in the front. Another Indian CD the announcer in a live concert is in the room.

What would be then the listening with high end OBs or those from Hari, Samir and other veterans in HFV

View attachment 88204
View attachment 88205
View attachment 88206
View attachment 88207

Enjoy them for a while. Even mate them with a tube amp if possible.

When you had your full and are ready for next big step. Just to do this, which comes from a veteran of the speaker designs :

https://www.madisoundspeakerstore.com/pdf/SB%20Audience%20OB3%20Open%20Baffle%20Kit.pdf

I am sure you can manage the build after your above first attempt.

 

[Subbu68]

Enjoy them for a while. Even mate them with a tube amp if possible.

The TUBE is in the left compartment of the TV rack that is closed in the photo. Elekit TU-8200 that has a fault in the heater circuit somewhere. Next is to repair it.

Now driven by twin ACA in bridged mono block mode. They are SS amps as you know but designed with some tubey sound it seems (as long as I don't use the balanced input mode).

 

[Subbu68]

@yogibear @Hari Iyer

Do you recommend isolating the OB from the floor with some kind of feet (even silicone bumpers)?