# Is this driver suitable for horn loading?



## EG92B16A (Jul 29, 2011)

I have the following drivers x 4, are they suitable for horn loading?
Etone 831, 200mm driver, treated paper cone.
fs - 41 Hz
Bl - 12.1
Qms - 3.59
Qes - 0.36
Qts - 0.33
Vas - 26.6L
Sd - 213.8 cm2
Spl - 90.3
Re - 6.8 ohm
Xmax - 4mm one way
Pe - 100W RMS

They seem to lack bass in the current ported enclosure of 26L.
I've tried using hornresp, but the program is confusing for someone new to it.
any help would be greatly appreciated.

cheers


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## chrapladm (Jun 17, 2009)

Making a horn using HR is easy. Making a good horn is not. SO what are you trying to get out of these 8's?

What are they in currently?


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## EG92B16A (Jul 29, 2011)

I'm looking to get better performance than they currently produce in a 26 ported box.
These are in Todds 802T towers. I have already modified the crossovers and changed the "mid" driver to another 8" more suited to the sealed box end of the cabinet. So 2 drivers are "spare".
The Winisd plot seems to be a -1.5Db EBS. Not too bad, but as always, more punch required.
I'm probably noticing it more because this is set up on my old Yamaha RXV390 amp. No sub out, and no subwoofers, so the lower octaves are really lacking. 
Probably not worth doing, but if I could get 30Hz out of these drivers without the box being the size of a fridge. then I might consider it.

Cheers


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## chrapladm (Jun 17, 2009)

Are you limited on space?

Your trying to use these 8's in a horn for what frequency range?


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## EG92B16A (Jul 29, 2011)

If I can get the bandwidth to 300Hz then I can probably make a decent 3 way system. And they will be used in my outdoor room so not space limited as such, but I could work with up to 300l.


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## chrapladm (Jun 17, 2009)

What have you tried to do in HornResponse?

I am no expert and truly a novice. I do a lot of designs myself but nothing amazing. More like "it will do the job," but nothing to write home about.

In HR(hornreponse) you can input the drivers T/S. Then go to system design and use with driver and see what you can come up with. Will have to change your expansion from Hyp to something like exp or other. You will have to look at the response shapes. Also make sure that the Vrc is also something you can build. Vrc is the volume that the driver will be in. SO 1liter wont work. You will need at least 4liters I believe. Maybe even 3liters with an 8.


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## EG92B16A (Jul 29, 2011)

I have tried entering the parameters and then doing system design by driver and I get horn sizes from 1000 to 3000l. Not sure what to do with segments and how to make the overall horn smaller. I've looked at a few other designs and the screenshots look different to what I get no matter what I do.:dontknow:
Cheers


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## chrapladm (Jun 17, 2009)

Ok so what do you want extension wise and upper cutoff?

If this is just a bass bin then you can try a FLH also. ALso can you tell me the dimensions of your ported cabinets for the pair of 8's?

Then I can simulate both and see how they compare. I threw a quick simulation together and got about 107db at 45hz with a 37hz Hpass. I am sure there can be more gained from a better design. This is just a thrown together guess.


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## EG92B16A (Jul 29, 2011)

OK, extension I'd like to get down to 30Hz or somewhere near 30Hz. Upper cut off not so critical, it'll be crossing to a 6" open baffle mid and peerless tweeter, but to save on cap costs probably 300Hz, tweeter crosses at 2.7KHz. Todds cabs are 90 x 21.5 x 25.5cm. 26L ported lower chamber and 20L sealed upper chamber.

Cheers


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## chrapladm (Jun 17, 2009)

This is just a ported alignment yes?

When I see upper chamber it makes me think of 6th order enclosures. ANY idea or port sizes in these enclosures?

SO far 26l would be ok for a 50hz port with a pair of drivers used. There are two drivers per 26 liters yes?

33hz in 50l with a pair of your drivers looks good. BUT 26l with anything lower than a 43hz port really rolls off. 50l does not roll off until port tune. Then needs a 29hz Hpass.


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## EG92B16A (Jul 29, 2011)

No. There's a single woofer in the sealed chamber with 100 uF cap, and a single woofer in the ported chamber with quite a large coil on it. The port is approx 50mm dia x 100mm long. I've since removed the cap so it's more like a 2.5 way system. I've measured these speakers in REW and there's a 10dB difference between bass and treble, hence trying to improve things a bit. If this isn't possible with the now left over drivers, I'll sell them and purchase some new 8" drivers and turn the boxes into a proper 3 way using dual bass drivers, 4 inch mid, and the peerless tweeter.

Cheers


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## chrapladm (Jun 17, 2009)

So bass is down 10db compared to the treble?

Best bet would be to use a pair of 8's in the ported enclosure and seal up the ports. This will bring up the sensitivity of the 8's from where the single was is at. 6db addition so that will help things out a lot. 

So you have a single driver and tweeter AND a pair of 8's you can use per cabinet or just a single 8 extra per cabinet?

A single 8 can only do so much. I built some towers with a single 8 but then added a side firing 12" subwoofer. The combo sounded GREAT. BUT there are so many ways of doing this.


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## EG92B16A (Jul 29, 2011)

Ok, so I'll design a new front baffle for the todds speakers. 2 x 8" woofers in 26l sealed enclosure, 1 x 8" mid woofer in 20l sealed enclosure, and peerless tweeter. Change driver spacing and offset between mid and tweeter to improve diffraction effects and adjust crossover.
Should this thread be moved to the speaker section now?

Cheers


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## chrapladm (Jun 17, 2009)

EG92B16A said:


> Ok, so I'll design a new front baffle for the todds speakers. 2 x 8" woofers in 26l sealed enclosure, 1 x 8" mid woofer in 20l sealed enclosure, and peerless tweeter. Change driver spacing and offset between mid and tweeter to improve diffraction effects and adjust crossover.
> Should this thread be moved to the speaker section now?
> 
> Cheers


I can move it later on to DIY speakers. BUT the 50mm, which is roughly 20cm2, with 100mm depth makes the port tuning 41hz in 26l. SO that is ideal for this 8" driver. From 30-73hz you will have more SPL from the single 8 ported than the dual sealed. Above and below you will have more SPL. BUT if you use a 35hz 1st order Hpass you can use double the amount of power for the sealed. Then your are only beat at 37hz-60. Just depends what your going for. Sounds like if the single ported is lacking in power then you may need some bigger bass drivers. Always try a dual 8" ported 41hz cabinet. If that doesnt do it you can try to take some REW measurements. Then after that if the treble is still to hot then add a 20Khz or so 1st order Hpass filter. That will make the tweeter not so hot.

So there are options to try if you feel like experimenting. Or just add a mid bass module under what you already have.


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## EG92B16A (Jul 29, 2011)

Just thinking out loud. No real gain by horn loading. 
The easiest option based on everything given so far, is to remove the internal partition creating one 48 odd litre box and run the two woofers in 2.5 configuration. Adjust the port diameter to 90mm stormwater and length to 15cm so we don't get chuffing. Hopefully 6dB more output up to 200Hz.

Cheers


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## chrapladm (Jun 17, 2009)

The setup looks good out to 500hz before roll off. Would be 6db more than what you have from about 45hz and up.


The faint gray line is what you have now.


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## EG92B16A (Jul 29, 2011)

Thanks chrapladm.

Now based on the response, should I add a dedicated mid driver, or just leave the setup as is with the 2.5 woofers? The tweeter is potentially crossed quite high with a 3.3 uF cap and a coil (that I haven't measured yet).
I'll post some response Graphs soon. I measured the tweeter and woofers separately.


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## chrapladm (Jun 17, 2009)

Well 2.5 would work but I do like having a dedicated midrange. Then let all the midbass be handled by a separate driver/s. I am not a speaker designer but from my amateur buildings of mixing up random drivers that is the opinion I have come to.


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## GPM (Jan 14, 2007)

EG92B16A said:


> I have the following drivers x 4, are they suitable for horn loading?


Yes, though not for the ~30-300 Hz decade desired BW since below Fs, power response rolls off fast and the compression ratio would be too high [~3.46:1] even to get it out to its ~227 Hz HF mass corner.

GM


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## EG92B16A (Jul 29, 2011)

Ok, so I have removed the front baffles and internal partitions from the boxes. I have laid out the new speaker locations and there's only space for a 5" max mid driver. The scanspeak 10f-4424 is available to me as is a couple of different 5" mids. Now I have to match up the tweeter efficiency and work out the baffle response.


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## EG92B16A (Jul 29, 2011)

So I have been playing around with a couple of baffle programs and have come up with a new design. I have implemented that design and built the new front panels, painted and glued them into place. Now I'm in the process of taking impedance measurements and getting some meaningful frequency response graphs. This is where I'm struggling. I'll post some graphs of what I've been getting. Maybe the shape of the response is due to where I'm taking the measurements. I'll post some pics soon.

Cheers


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