Home » Audio » Speaker » Integrating full-range as wide-range
Integrating full-range as wide-range [message #21565] Mon, 05 June 2006 09:42 Go to next message
GarMan is currently offline  GarMan
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Registered: May 2009
Illuminati (2nd Degree)
After listening to my Goodmans Axiette 8 II's for a week, I'm still very impressed by it. However, it's obvious it's missing the very top and bottom end. The top end's easy. I simply added a set of piezos I had lying around, crossed at 10kHz, and the improvement was immediately noticable. What I need help on is integrating the bottom end, specifically cabinet design.

I have a pair of JBL 2235, each in its own 5 ft^3 cabinets that I use in my main system. The bass from these are incredible and would complement the Goodmans well. I'm sure I can get "good" bass from the Goodmans with a well aligned cabinet, but it will never be as deep and loud as the JBL's.

Questions:

If I intend to integrate the Goodmans with the JBLs, can I get away with a simple sealed box? I like to keep the cabinet as small and simple as possible. I know that a larger vented box, or even BLH can extend the bass lower, but what are the advantages of taking the fullrange down to, say, 50Hz if I'm using a "sub"?

If the sealed box is okay, what size? There's little to none information on the web about these speakers. From this forum's experience with similar drivers, how low will it go in a sealed enclosure? The drivers currently sit in a 2 ft^3 vented.

thx,
Gar.

Re: Integrating full-range as wide-range [message #21571 is a reply to message #21565] Tue, 06 June 2006 06:19 Go to previous messageGo to next message
akhilesh is currently offline  akhilesh
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Registered: May 2009
Illuminati (3rd Degree)
HI Gar,
You can use a sealed box, but then your JBLs will be doing work till about 150-200 Hz. THis will cause imaging/coherence issues. My suggestion is to measure the axiettes and build a BR box for them, then cross them over an octave higher with the JBLs. My guess is the axiettes should be capable of producing 50 Hz or so in a well designed BR box. Design a box that does that (you'll have to measure the drivers to be sure of course) and then cross over an octave higher. Try different slopes. i'd start with at least a 12 db slope each way.
This will give you coherence and imaging.
-akhilesh

Re: Integrating full-range as wide-range [message #21576 is a reply to message #21571] Tue, 06 June 2006 10:56 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
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Registered: January 2001
Illuminati (33rd Degree)

The trade-off, of course, is that as you crossover the main driver lower, you increase IMD. You don't want that because it's really objectionable in the vocal range. I'd pick the crossover based on the distance between sub and main, and make sure it didn't exceed 1/4λ. That's the main thing that will affect summing between the sub and main driver.


Re: Integrating full-range as wide-range [message #21578 is a reply to message #21576] Wed, 07 June 2006 11:19 Go to previous messageGo to next message
akhilesh is currently offline  akhilesh
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I agree, Wayne. That's why i like to cross the wide range an octave higherthan it can produc (kinda like my trusonics which I cross at around 90 Hz). OF course each driver is different.
-akhilesh

Re: Integrating full-range as wide-range [message #21579 is a reply to message #21578] Wed, 07 June 2006 14:31 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
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Registered: January 2001
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Sounds reasonable. I like the sound of your Trusonic + sub system, by the way.


Re: Integrating full-range as wide-range [message #21582 is a reply to message #21579] Wed, 07 June 2006 15:41 Go to previous messageGo to next message
akhilesh is currently offline  akhilesh
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I know. You need to visit and hear my stuff soon. Lunch sometime soon (my treat)?
-akhilesh

Re: Integrating full-range as wide-range [message #21583 is a reply to message #21582] Wed, 07 June 2006 18:13 Go to previous messageGo to next message
GarMan is currently offline  GarMan
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Registered: May 2009
Illuminati (2nd Degree)
Akhilesh,

When you crossed your fullrange to sub, did you apply any high pass on the fullrange, or did you just let it die out naturally?

Re: Integrating full-range as wide-range [message #21584 is a reply to message #21582] Wed, 07 June 2006 21:28 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
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Registered: January 2001
Illuminati (33rd Degree)

Sounds great - It's a plan.


Re: Integrating full-range as wide-range [message #21587 is a reply to message #21583] Thu, 08 June 2006 21:39 Go to previous messageGo to next message
akhilesh is currently offline  akhilesh
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Registered: May 2009
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I applied a highpass on the full range. 24db.
That's what the active does. If you want the fullrange to die out naturally, as you know, there are 2 issues at least:
1. WE need to calculate the slope of die out and then calculate the low pass slope on the sub so thee summing is zero ro whatever we want
2. We don't reduce the IM distortion: in my opinion the main advantage to the use of a sub.

For example, my trusonic can do 45 hz in its BR box. So if is let it die naturally i'd probably be crossing it at 24 db at around 40 db. But the IM distortion would be the same as without a sub.
Crossing it actively at 90 hz takes care of that.
It actually sounds significantly better: the results of IM distortion are not the phantom metrics that plague the dreams of many "speaker designers", it's very clearly audible.
Hoep this helps
-akhilesh


Re: Integrating full-range as wide-range [message #21588 is a reply to message #21587] Fri, 09 June 2006 07:14 Go to previous messageGo to previous message
GarMan is currently offline  GarMan
Messages: 960
Registered: May 2009
Illuminati (2nd Degree)
I completely agree on IM. I've built a couple of sets of speakers using 3" Tangbands fullrange, and the effects of 100uF in series with woofer was tremendous. Completely cleaned up the mids and highs and improved power handling.

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