Making my own larger center channel out of my q100

[Nwickliff]

Hey everyone, I'm trying to figure out how I can add a couple of 6" woofers to my q100 in a larger box in order to relieve the mid and gain more low-end extension into the 60hz region. Currently, with my speaker in the entertainment center under the tv, it poops out at 100hz and my subs don't naturally reach that high in my room. Should I just eq the subs to do so? As I'm writing this I'm also realizing it might make sense to place one of my bookshelves that I know reach down to 40hz in the cabinet to see if the same issue persists, as no speaker will "fix" that issue if it's more placement dependent

Still, I think it would be pretty sweet to build my own larger "kef" q100 type, speaker.

Erinsaudiocorner already has so much data on the driver. Is this info all I would need to simulate box and crossover after adding 2 woofers?

Kef Q100 Speaker Drive Unit Testing

Kef Q100

www.erinsaudiocorner.com

how do I get the info into xsim for xo design?

Can you add more than a single driver to winISD to simulate the size of the box and port needed for bass extension?

 

[ernestcarl]

I'm also realizing it might make sense to place one of my bookshelves that I know reach down to 40hz in the cabinet to see if the same issue persists, as no speaker will "fix" that issue if it's more placement dependent

Absolutely! You gotta find out first if the placement of a speaker with deeper bass extension works well enough in there. Otherwise, it might be more of an exercise in futility.

Can't comment with speaker design, though, sorry.

 

[Nwickliff]

Absolutely! You gotta find out first if the placement of a speaker with deeper bass extension works well enough in there. Otherwise, it might be more of an exercise in futility.

Can't comment with speaker design, though, sorry.

Thank you. I'll be giving this a try today to see if I can get lower extension. Could be this 120hz resonance that is just sucking up everything on either side of it too. wonder if I could just build a box that fits more snug in the space if that would help with the resonance.

 

[ernestcarl]

Thank you. I'll be giving this a try today to see if I can get lower extension. Could be this 120hz resonance that is just sucking up everything on either side of it too. wonder if I could just build a box that fits more snug in the space if that would help with the resonance.

It's very likely a room and placement issue.

See Amir's spinorama:

I believe with a speaker that has more bass below 100Hz, you might get anywhere between 3-5dB broad boost. It would lessen the impact of 60Hz dip overall, but it's still gonna be there nonetheless. But I think it would still be an improvement if paired with a sub(s).

 

[Nwickliff]

It's very likely a room and placement issue.

See Amir's spinorama:

I believe with a speaker that has more bass below 100Hz, you might get anywhere between 3-5dB broad boost. It would lessen the impact of 60Hz dip overall, but it's still gonna be there nonetheless. But I think it would still be an improvement if paired with a sub(s).

Even there though, it's starting to roll off at 150hz! Everything I have to try is rear-ported too, so we'll see how that goes...yikes.

 

[alex-z]

The data from Erins audio corner is not quite what you need. It only has 0, 30, and 60 degree data, and is done on a large test baffle, the response in an actual speaker cabinet will be considerably different. This is due to baffle step loss and edge diffraction.

You need to make your own horizontal and vertical measurements with the drivers flush mounted in the cabinet. The Q100 woofer should be isolated in its own sealed air volume, while your 6" woofers have their own ported air volume (or sealed if it suits the design better).

How to make quasi-anechoic speaker measurements/spinoramas with REW and VituixCAD

Quasi-anechoic measurements are a way to capture the 'real' frequency response of a speaker without the influence of a room. They are called 'quasi-anechoic' because they have the potential to get you really close to the results one might achieve with a non-reflective environment like an...

www.audiosciencereview.com

That data can then be used to do proper crossover design in VituixCAD. Don't use Xsim, it is vastly inferior, it doesn't even have off-axis response modelling. VituixCAD also has cabinet modelling for bass extension, so you don't even need WinISD.

Keep in mind that the Q100 woofer is below 4 Ohms by itself. Converting it to a 3 way design could result in even lower impedance, necessitating an amplifier which is 2 Ohm stable, a rarity outside of pro-audio gear like a Crown XLS1002.

Your issue is likely due to placement, but the 3 way design is a good choice nonetheless. Using a pair of 6" woofers will give you greater headroom to apply EQ, and improve overall sound quality. This is because the Q100 woofer will undergo less excursion, so inter-modulation distortion goes down, and the woofer also serves as a waveguide for the tweeter. Less excursion means the waveguide doesn't move as much.

 

[voodooless]

Keep in mind that the Q100 woofer is below 4 Ohms by itself. Converting it to a 3 way design could result in even lower impedance, necessitating an amplifier which is 2 Ohm stable, a rarity outside of pro-audio gear like a Crown XLS1002.

No, it would not. the crossover will take care of this just fine. If done right, it won't be a worse load on the amp.

I don't know how VituixCAD works, but it might be able to convert the standardized measurements on a large to something simulatable. In any case, real measurements will be needed to make a proper crossover though. If passive, also impedance should be measured, but you might get away with modeling that.

Do you have a budget in mind for the build?

 

[Trouble Maker]

Simple way might be 2 separate boxes to the left and right of the Q100 w/(1 each) 6" woofers. Make a separate (project) box for a cross-over w/1in/3out to the 3 boxes. This also wouldn't cannibalize the Q100, nor effect it's performance (assuming the HPF to the Q100 has no ill effect). This may put the center-to-center spacing of the 6"ers further out that if you put them all in a purpose built box together, but as long as crossover is low enough it should be fine. If you bias the 6" towards the Q100 rather than centered in their own enclosures this would help.

Beyond these (simple) ideas, if it will help and how to build; it seems like there's already great help above beyond what I can offer.

 

[Trouble Maker]

Alternatively I wonder if you could find some small/slim (6" or 8") powered 'sub'woofer w/speaker level in/out that would fit below the center where the AVR currently is. Then put the AVR in one of the side compartments, assuming it also fits. If such a thing exist at an inexpensive price point, it could be the path of least resistance from a time and cost standpoint. I imagine something in that size range is likely to typical produce the frequency range that you need and not actual sub frequencies.

Something like this, but with speaker level in/out https://www.crutchfield.com/S-r0MDW6VAxiN/p_701S808SWB/Jamo-S-808-SUB-Black.html?
This was what first came to mind, but I thought they also had a smaller one. This is likely to be too big and overkill. https://www.parts-express.com/Dayton-Audio-SUB-1000L-10-100-Watt-Low-Profile-Powered-Subw-300-639
Or a non-powered one would work and still make or buy an external passive crossover, but this fees pie-in-the-sky to produce down to the frequencies you need even though it claims 40hz. https://www.parts-express.com/Dayton-Audio-MKSX4-Four-4-Driver-Low-Profile-Passive-Subwoofer-300-495

Anyway, none of those are exactly the right solution, but just examples to give an image of the idea. Maybe someone here knows of a right solution for this concept.

 

[Nwickliff]

The data from Erins audio corner is not quite what you need. It only has 0, 30, and 60 degree data, and is done on a large test baffle, the response in an actual speaker cabinet will be considerably different. This is due to baffle step loss and edge diffraction.

You need to make your own horizontal and vertical measurements with the drivers flush mounted in the cabinet. The Q100 woofer should be isolated in its own sealed air volume, while your 6" woofers have their own ported air volume (or sealed if it suits the design better).

How to make quasi-anechoic speaker measurements/spinoramas with REW and VituixCAD

Quasi-anechoic measurements are a way to capture the 'real' frequency response of a speaker without the influence of a room. They are called 'quasi-anechoic' because they have the potential to get you really close to the results one might achieve with a non-reflective environment like an...

www.audiosciencereview.com

That data can then be used to do proper crossover design in VituixCAD. Don't use Xsim, it is vastly inferior, it doesn't even have off-axis response modelling. VituixCAD also has cabinet modelling for bass extension, so you don't even need WinISD.

Keep in mind that the Q100 woofer is below 4 Ohms by itself. Converting it to a 3 way design could result in even lower impedance, necessitating an amplifier which is 2 Ohm stable, a rarity outside of pro-audio gear like a Crown XLS1002.

Your issue is likely due to placement, but the 3 way design is a good choice nonetheless. Using a pair of 6" woofers will give you greater headroom to apply EQ, and improve overall sound quality. This is because the Q100 woofer will undergo less excursion, so inter-modulation distortion goes down, and the woofer also serves as a waveguide for the tweeter. Less excursion means the waveguide doesn't move as much.

Thank you. I will be checking out VituixCAD. So first step is designing a box I guess. Can WinISD do multiple drivers in a single enclosure? Is there a better program to see how large the box can be OR....Should I just design the box to fit perfectly in the cabinet and then just design the crossover from there. Hard to go too big for the drivers given the space it needs to fit in.

 

[Nwickliff]

Simple way might be 2 separate boxes to the left and right of the Q100 w/(1 each) 6" woofers. Make a separate (project) box for a cross-over w/1in/3out to the 3 boxes. This also wouldn't cannibalize the Q100, nor effect it's performance (assuming the HPF to the Q100 has no ill effect). This may put the center-to-center spacing of the 6"ers further out that if you put them all in a purpose built box together, but as long as crossover is low enough it should be fine. If you bias the 6" towards the Q100 rather than centered in their own enclosures this would help.

Beyond these (simple) ideas, if it will help and how to build; it seems like there's already great help above beyond what I can offer.

This is an interesting idea. I think my wife might have a heart attack as it would take weeks of fiddling with wires everywhere at the entertainment center. She can't stand the wires and clutter.

 

[beagleman]

Hey everyone, I'm trying to figure out how I can add a couple of 6" woofers to my q100 in a larger box in order to relieve the mid and gain more low-end extension into the 60hz region. Currently, with my speaker in the entertainment center under the tv, it poops out at 100hz and my subs don't naturally reach that high in my room. Should I just eq the subs to do so? As I'm writing this I'm also realizing it might make sense to place one of my bookshelves that I know reach down to 40hz in the cabinet to see if the same issue persists, as no speaker will "fix" that issue if it's more placement dependent

Still, I think it would be pretty sweet to build my own larger "kef" q100 type, speaker.

Erinsaudiocorner already has so much data on the driver. Is this info all I would need to simulate box and crossover after adding 2 woofers?

Kef Q100 Speaker Drive Unit Testing

Kef Q100

www.erinsaudiocorner.com

how do I get the info into xsim for xo design?

Can you add more than a single driver to winISD to simulate the size of the box and port needed for bass extension?

What bookshelf speaker do you own, that you "know" reaches down to 40Hz???

That may be the main issue, you have your sub crossing too low, and assume your left and right sats are going lower than they truly are.
Try raising the sub crossover to 100hz and see how it works first.

 

[Colonel7]

What bookshelf speaker do you own, that you "know" reaches down to 40Hz???

That may be the main issue, you have your sub crossing too low, and assume your left and right sats are going lower than they truly are.
Try raising the sub crossover to 100hz and see how it works first.

Definitely do this first. You should do some measurements to because you could have a room issue at the LP for certain frequencies.

WinIsd can model multiples of the same driver in same box. I wouldn't try DIYing it as a 3-way unless you're prepared to do a lot of work: measuring each driver, building a visually acceptable box, and having wires take up residence for awhile as you test, measure, listen and tweak. A lot more effort with a 3-way too. It's fun but whether your spouse thinks so is another question. The chair is part of the improvised anti-labrador defense system.

 

[TheBatsEar]

Alternatively I wonder if you could find some small/slim (6" or 8") powered 'sub'woofer w/speaker level in/out that would fit below the center where the AVR currently is.

Not sure how far up the subwoofer would play, but could you not just cut off the woofer at 100Hz hard with a DSP and give the rest to a subwoofer anywhere in the room? I have let subwoofers play up to 120Hz and nobody noticed.