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BR + TL + FH [message #20342]

Fri, 03 September 2004 13:24

Ralph
Messages: 75
Registered: May 2009

Viscount

I'm looking hard at making a FR speaker and a light bulb went on. What if I use a front horn for mids and highs, a rear TL that was proper length for midbass and ported low for the very deepest bass?
Ralph

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Re: BR + TL + FH [message #20343 is a reply to message #20342]

Fri, 03 September 2004 17:29

robertG
Messages: 24
Registered: May 2009

Chancellor

Except for the TL, reminds me of an Altec A7 (small front horn and BR for - not so low - bass).

By the way, unless I don't get it, BR and TL are mutually exclusive.

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Re: BR + TL + FH [message #20344 is a reply to message #20343]

Fri, 03 September 2004 17:55

Ralph
Messages: 75
Registered: May 2009

Viscount

I'm thinking of a dual horn concept. The front wave fires into a front horn as you say. The rear wave fires into a 24" pipe for ~150hz TL. The pipe volume and the port opening would also make a Helmholtz cavity so I could size the port for ~60hz. What do you think of this staggered tuning arrangement?

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Re: BR + TL + FH [message #20345 is a reply to message #20342]

Fri, 03 September 2004 18:58

Martin
Messages: 220
Registered: May 2009

Master

Hi Ralph,

I think that the problem you are going to run into is that the front horn will raise the efficiency of the driver's output and the TL (or BR) at the back will only match the driver's original efficiency. You will end up with a very weak bass output once you factor in the baffle step response and the elevated mids and highs.

I think the only possibility would be to mate a short front loaded horn for the mids and highs and a longer bigger back loaded horn for the bass. You could arrange these two horns to acoustically "cross-over" at the same frequency. The design work would be a little tricky but I don't think it is impossible. I have been thinking about this type of two horn system a lot lately, I just need to find time to merge the two computer models I wrote for the front and back loaded horns to see what results I can achieve.

Hope that helps,

Martin

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Re: BR + TL + FH [message #20346 is a reply to message #20345]

Fri, 03 September 2004 20:03

akhilesh
Messages: 1275
Registered: May 2009

Illuminati (3rd Degree)

Hi Ralph & Martin,
Woudn't bi/tri-amping solve it? The efficiency issues I mean?
thanx
-akhilesh

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Re: BR + TL + FH [message #20347 is a reply to message #20346]

Sat, 04 September 2004 06:34

Martin
Messages: 220
Registered: May 2009

Master

akhilesh,

Yes, bi/tri-amping might help if it was a multi-driver speaker. But in the single driver speaker concept I am not sure how it would be done. I guess the other option is to put a severe shaping filter in the system to blend the bass with the mids and highs but that seems to be taboo for most single driver users.

Martin

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Re: BR + TL + FH [message #20348 is a reply to message #20347]

Sat, 04 September 2004 12:34

akhilesh
Messages: 1275
Registered: May 2009

Illuminati (3rd Degree)

HI Martin,
DUH! Sorry, I didn't read the post carefully, I thought it was for a multi way speaker.
Yeah, for a single driver, i guess there is no way that I can think of. A shaping filter is a good consideration, as we have discussed before.
thanx
-akhilesh

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Re: BR + TL + FH [message #20349 is a reply to message #20344]

Sat, 04 September 2004 19:09

robertG
Messages: 24
Registered: May 2009

Chancellor

This require some thoughts! At first, I would beleive that the setup would be high-mid heavy. Did you try to model it in sim software?
Would it be superior to a FH + BH setup? In my experience, a back horn will "boost" output from probably 50Hz all the way to 300 Hz, which might be all you need. On the other hand, your idea would probably yield to a smaller (and easier to design) and more convenient (as in WAF) package... Hum...

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Re: BR + TL + FH [message #20350 is a reply to message #20344]

Sat, 04 September 2004 19:28

roncla
Messages: 125
Registered: May 2009

Master

All depends on the FR curve of the driver and what boost in what range you are looking for.
I am working on a FLH/BLH at the moment using the Fe-206e. But if you look at the rising response of the 206e(typical of low Qts full range drivers) you will see it needs boost in the lows and mids to bring it up to the higher response level of the higher frequencies.If a driver had near a totally flat FR curve and just needed a boost in the lower frequencies then you have to design around that requirement.
The trick is getting close to equal loading(not physically possible to get equal) and making the mechanical XO blend and getting the correct range and amount of boost needed.
This could all be solved with multiple drivers in seperate cabs with bi or tri amping........but whats the fun in that?
ron

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Acoustic versus electrical shaping? [message #20351 is a reply to message #20345]

Sun, 05 September 2004 07:16

akhilesh
Messages: 1275
Registered: May 2009

Illuminati (3rd Degree)

Hi MArtin,
I read the posts here again, this time a little more carefully. Do you think that the system will sound different with an electric circuit doing the frequency shaping, versus the back loaded horn?
The only differences I can see are:
1. The horn will actually amplify frequencies as opposed to suppressing them
2. The efficiency of the system will be higher.

With solid state amps, would that be an issue?
thanx
-akhilesh

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