Are there any inherent disadvantages to using open back drivers for mid range of a 2-way Synergy horn (while the tweeter would stay a compression driver) so that the front and back waves are allowed to interact, like a dipole?
Kind of defeats the purpose when one of the major advantages of a constant directivity MEH is to minimise the amount of reflected sound in the room.
I see no benefit to an open back synergy style horn.
I see no benefit to an open back synergy style horn.
I am a bit enamored with the open baffle sound at lower and lower mid frequencies and horn sound at the top end. So, I wondered if an open back lower mids in a Synergy horn could be a way to hear some of the dipole magic, even if means to see dipole cancellation along the axis. In a broader sense, u-frame, open baffle and horn are just structures where their "wings" progressively curving forward, towards the driver.
I wonder if a Synergy horn with with extremely wide angle of dispersion might give best of the both worlds?
Open baffle has better separation of direct to indirect sound and better directivity in the dipole region.
In a synergy horn, the mids go from controlled directivity (highs) to omni at some low frequency within their bandwidth. Operating them in dipole in this frequency is the only reason why they may sound better than sealed. I started a similar thread but it didnt go as expected.
How to model a driver in a dipole waveguide?
After asking around and googling, I figured the best option is to go 4-way. Low and low-mid handled by H-frame/OB, and high-mid and high going into a unity horn. Hopefully, that makes engineering sense.
It makes sense to you...
I would be cautious seeking affirmation of the idea in an "engineering sense" as you will get more opinions than you get answers.
Here is my opinion....
As an "engineer" I get the idea of a high efficiency system. A unity horn and high efficiency sub / bass is consistent with this.
Open baffle is not high efficiency- certainly not at low frequencies. So mixing the two, open baffle and horn, strikes me as a personal choice rather than logical.
I would be cautious seeking affirmation of the idea in an "engineering sense" as you will get more opinions than you get answers.
Here is my opinion....
As an "engineer" I get the idea of a high efficiency system. A unity horn and high efficiency sub / bass is consistent with this.
Open baffle is not high efficiency- certainly not at low frequencies. So mixing the two, open baffle and horn, strikes me as a personal choice rather than logical.
The choice is indeed based on personal listening preferences. Coupled with OBs, the horns should be run at pretty low power but that will only lend to dynamics. My interest in efficiency has more to do with dynamics than loudness.
It seems that the Unity horn is effective above 600 Hz, within reasonable dimensions, even though I can work less perfectly below 600 Hz.
One idea is to have two H-frame 15" double woofers on each side to compensate for loss of OB low end. The lower mid can be incorporated into the horn to make it a 3-way.
What do you think would be a more logical design choice?
Answers and opinions are both welcome 🙂
And what sub bass do you prevere as a high efficient system? tapped horn, closed box, slotted sub or just a plain horn (big).
regards
Not aware of what omni synergy is. Google doesn't seem to throw up any speakers. Please share any link you have.
There isn't one, but this is DIY 😉 It appears that you want wide dispersion so why not make an omni source with coincident ranges.
Hmm, I was trying to show a way to do the same thing as you. Earlier I was confused (and am again now) whether you saw the open baffle as giving directivity or adding spaciousness, since the two are unrelated (in speakers) but often mixed up. Do you want less sound to the sides or more to the back? That 'dipole sound' is a side effect of the backwave.
The draw of OB at the low end is the lack of boxiness and the sense of encompassment. While I like the dynamics and response of horns at the higher end, where OB sounds too diffuse and lacking impact. I was wondering if there is a way to incorporate a low mid 8" in a four-way where woofer is OB and the high mid and high are a unity horn.
Kees, re: And what sub bass do you prevere as a high efficient system? tapped horn, closed box, slotted sub or just a plain horn (big).
i have done them all except slotted sub.
The only configurations I would describe as efficient are the horn loaded subs.
The 25Hz horn loaded subs I built were awesome but pretty darn big and heavy. They would be a decent efficiency match to a unity horn. They bring dynamics and SPL that I doubt could be achieved by any sane number of OB drivers.
I am only partly sold on Tapped Horns due to limited bandwidth. Their efficiency is highly driver and implementation dependent, and in my experience not up there with more conventional horn loaded arrangements - but in a good setup better than a reflex arrangement over a narrow bandwidth.
After that vented and closed box are if you like a "benchmark" of neutral efficiency.
Open baffle is at lower frequencies quite inefficient. it is battling the laws of physics unless you increase the baffle size to virtually infinite.
i have done them all except slotted sub.
The only configurations I would describe as efficient are the horn loaded subs.
The 25Hz horn loaded subs I built were awesome but pretty darn big and heavy. They would be a decent efficiency match to a unity horn. They bring dynamics and SPL that I doubt could be achieved by any sane number of OB drivers.
I am only partly sold on Tapped Horns due to limited bandwidth. Their efficiency is highly driver and implementation dependent, and in my experience not up there with more conventional horn loaded arrangements - but in a good setup better than a reflex arrangement over a narrow bandwidth.
After that vented and closed box are if you like a "benchmark" of neutral efficiency.
Open baffle is at lower frequencies quite inefficient. it is battling the laws of physics unless you increase the baffle size to virtually infinite.
From working with other horns reactance annulling, or putting the driver in a small rear enclosure can reduce HD and tighten things up.
What was the design you used to make a 25Hz sub? Please share photos, information etc.