I was flipping through YouTube and noticed a company named Perfect8. They build a Small monitor with midrange Drivers on both sides opposing each other and the tweeter facing forwards. Just curious if other companies have used this mounting technique and what the advantages/disadvantages would be? I’m assuming the crossover frequency is pretty low (1khz area)?
I can't imagine acoustic concerns are very high up their list of priorities with them selling such highly resonant undamped enclosures.
I’m just thinking of the locations of the midrange units. I’ve never heard them so I can’t comment on how the sound.
Glass Cabinets
I assess Perfect8's choice of glass cabinets a bit differently. Glass is a high Q material, and as such, rings greatly over a relatively narrow bandwidth. However, this also renders glass relatively easy to damp via a proper mechanical terminating impedance located at the right place. This is simple to demonstrate to oneself right now via an example Ted Jordan suggested.
Get two drinking containers from your kitchen. Set them on a table. Lightly strike each container with a metal dinner knife. The glass container will ring greatly because it's a high-Q material, while the plastic container makes more of a brief 'thunk' sound, because it's a low-Q material.
Now, repeat both knife strikes, but this time rest a finger on the lip of each container before you strike it. The sound character of the plastic container changes little, but the glass container emits only a very briefly transient, colorless 'tick' sound. Your finger terminates the high-Q glass with a lossy impedance placed at the right location of the structure, quickly damping its relatively narrow resonance band and leaving little sound contribution of it's own. The plastic container, however, is permanently self-damped, so its relatively broad low-Q resonance band is makes it much more difficult, if impossible, to remove the residual colored resonance.
I suspect this logic underpins Perfect8's strategy of utilizing glass cabinets. Terminated effectively, glass cabinets are relatively colorless, acoustically.
I assess Perfect8's choice of glass cabinets a bit differently. Glass is a high Q material, and as such, rings greatly over a relatively narrow bandwidth. However, this also renders glass relatively easy to damp via a proper mechanical terminating impedance located at the right place. This is simple to demonstrate to oneself right now via an example Ted Jordan suggested.
Get two drinking containers from your kitchen. Set them on a table. Lightly strike each container with a metal dinner knife. The glass container will ring greatly because it's a high-Q material, while the plastic container makes more of a brief 'thunk' sound, because it's a low-Q material.
Now, repeat both knife strikes, but this time rest a finger on the lip of each container before you strike it. The sound character of the plastic container changes little, but the glass container emits only a very briefly transient, colorless 'tick' sound. Your finger terminates the high-Q glass with a lossy impedance placed at the right location of the structure, quickly damping its relatively narrow resonance band and leaving little sound contribution of it's own. The plastic container, however, is permanently self-damped, so its relatively broad low-Q resonance band is makes it much more difficult, if impossible, to remove the residual colored resonance.
I suspect this logic underpins Perfect8's strategy of utilizing glass cabinets. Terminated effectively, glass cabinets are relatively colorless, acoustically.
The two mids sum to the front and rear of the speaker. You get increased volume to the front and rear below a certain frequency range.
Another way to do that is to use only one midrange driver in an open-baffle dipole design. One speaker, no enclosure. Like the Perfect 8, you'd get increased volume to the front and rear with less volume on the sides.
Another way to do that is to use only one midrange driver in an open-baffle dipole design. One speaker, no enclosure. Like the Perfect 8, you'd get increased volume to the front and rear with less volume on the sides.
Are there any advantages to doing this? I’ve only seen one brand employee this technique so my first thought is no.
I heard the small system 'the cube' or something like that at hifi show, and it was the weirdest most unnatural sound at that show
I was not so concerned about enclosure structural resonance, but the total lack of any back wave absorption. All the sound that goes into the box from the driver will come straight back out of the box through the speaker cone. Undamped boxes sound REALLY bad. Talk into that glass drinking container with your finger on the side and you will quickly understand what I mean.
My mistake then, I assumed that you were referring to their unusual choice of enclosure material. I concur, that secondary emission via the driver cone is a big problem unless effectively mitigated. Perhaps, they didn't use any internal absorptive material because it would have been unsightly as seen through the transparent cabinet? Aesthetics over sound.
That speaker is "clearly" designed at a particular class of ignorance. They simply can't work to deliver hi-fi stereo for so many reasons - no matter what la-de-dah "high end" BS brand of amplifier and DAC might be put ahead of them. The YouTube reviewer is a typical proud yet ignorant spouter of audiofoolery and ought to be ignored.
Perfectly summed up in just three words.
BTW, SimpleSQ, sorry this thread meandered so far off course. I see few legitimate acoustic reasons for the side mounted mids. Their are so many fatal flaws in this design the placement of the mids is minor compared to the rest. You should have chosen a less controversial design for discussion.😱
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I wonder what these sound like?
HP’s VINTAGE REVIEW 2: Bosendorfer VC-7 Loudspeakers >> Adventures in Hifi Audio
They also have side firing mid and bass drivers.
HP’s VINTAGE REVIEW 2: Bosendorfer VC-7 Loudspeakers >> Adventures in Hifi Audio
They also have side firing mid and bass drivers.
As do the Sunfire Cinema Ribbon CRM-2
If the crossover is low enough they could work well.
Measured here: Sunfire Cinema Ribbon CRM-2 Speaker System HT Labs Measures | Sound & Vision
Far from best in class but they might suit some people.
If the crossover is low enough they could work well.
Measured here: Sunfire Cinema Ribbon CRM-2 Speaker System HT Labs Measures | Sound & Vision
Far from best in class but they might suit some people.
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Maybe they're trying to overcome some problem the open baffle dipole runs into. They get the figure 8 pattern through summation rather than subtraction so maybe it is designed to work with a lower power amplifier. Maybe it reproduces lower frequencies with smaller drivers better than an open baffle. I don't know.
This is the first time I've seen the Perfect8 but the Kii Three is similar. The Kii adds an additional woofer to the front out of phase with the side drivers. In that case it shifts the relative volume level from front and back to front only.
Attachments
Kii Three uses the side mount drivers for a completely different purpose. With the help of DSP the side mount drivers are used to force a cardioid polar pattern at low frequencies.
Perfect8 would be omni at low frequencies.
Perfect8 would be omni at low frequencies.