Josh,
Yeah, I definitely prefer the B&C driver compared to the BMS in the same wave guide. I'm not sure exactly how to articulate it, but the B&C is more relaxed, more natural and has more body - it has some depth to it that the BMS seems to lack. It's just plain smoother all the way around and it's not as dry as the BMS. I listen mostly to jazz anymore and saxophones sound more real with the B&C, more organic or something.
If I had to keep only one, the B&C would win hands down.
Yeah, I definitely prefer the B&C driver compared to the BMS in the same wave guide. I'm not sure exactly how to articulate it, but the B&C is more relaxed, more natural and has more body - it has some depth to it that the BMS seems to lack. It's just plain smoother all the way around and it's not as dry as the BMS. I listen mostly to jazz anymore and saxophones sound more real with the B&C, more organic or something.
If I had to keep only one, the B&C would win hands down.
hey Brett
Initial impressions of the 1086 with the B&C DE250 drivers is not good. Very peaky between ~3khz and ~6khz. It'll take a notch to flatten. Small sweet spot, weird kinda muffled sound...maybe a bad horn/driver mismatch???
I don't have a lot of time over the next few days to mess with it, so I'll probably just throw the BMS drivers in and see how they do. So far, the ENG90 seems to be the ticket for the B&C driver.
Initial impressions of the 1086 with the B&C DE250 drivers is not good. Very peaky between ~3khz and ~6khz. It'll take a notch to flatten. Small sweet spot, weird kinda muffled sound...maybe a bad horn/driver mismatch???
I don't have a lot of time over the next few days to mess with it, so I'll probably just throw the BMS drivers in and see how they do. So far, the ENG90 seems to be the ticket for the B&C driver.
AJ said:
Have you applied constant directivity equalization?
Have you measured the response of the speaker?
Are you shaping the response of the compression driver?
The response of an unequalized compression driver on a waveguide is ANYTHING but flat.
If you're recommending one compression driver over another, when neither one is flat, that's not fair is it?
"If you're recommending one compression driver over another, when neither one is flat, that's not fair is it?"
Whoever said life was fair? In the tiny tiny world of my personal preferences, I'm god, king, and undisputed ruler of my domain. It's not a democracy, it's a monarchy, and whatever I say for myself, is absolute law.
I'm not recommending anything Patrick, as I've made very clear from the start. I'm just throwing a bunch of components together, doing enough EQ to get things reasonably flat, and then comparing them. It's all just a baptism of CD/waveguides for me, and I've never implied anything else. If I say it needs a notch, it's because there's an easily measured and heard peak there. When I have time, I'll notch it.
Once again, YMMV.
Whoever said life was fair? In the tiny tiny world of my personal preferences, I'm god, king, and undisputed ruler of my domain. It's not a democracy, it's a monarchy, and whatever I say for myself, is absolute law.
I'm not recommending anything Patrick, as I've made very clear from the start. I'm just throwing a bunch of components together, doing enough EQ to get things reasonably flat, and then comparing them. It's all just a baptism of CD/waveguides for me, and I've never implied anything else. If I say it needs a notch, it's because there's an easily measured and heard peak there. When I have time, I'll notch it.
Once again, YMMV.
Q
When I first used the little neo compression driver from BMS, I was disappointed because it sounded thin, and it couldn't cross over as low as the JBL I'd used in a previous project.
So my initial impression was poor.
Then I applied CD EQ, and the sound of the driver was *transformed.* Once it's response was shaped, I was shocked by the extended response. The JBL could never hope to reach 20khz. The JBL certainly could play lower, but it couldn't compete with the BMS in the top octave.
My point is that I wouldn't have realized how GREAT the BMS could be until I shaped it's response.
Waveguides do NOT measure flat.
They aren't SUPPOSED to measure flat.
They're not horns.
They REQUIRE constant directivity EQ.
SamL said:
When I first used the little neo compression driver from BMS, I was disappointed because it sounded thin, and it couldn't cross over as low as the JBL I'd used in a previous project.
So my initial impression was poor.
Then I applied CD EQ, and the sound of the driver was *transformed.* Once it's response was shaped, I was shocked by the extended response. The JBL could never hope to reach 20khz. The JBL certainly could play lower, but it couldn't compete with the BMS in the top octave.
My point is that I wouldn't have realized how GREAT the BMS could be until I shaped it's response.
Waveguides do NOT measure flat.
They aren't SUPPOSED to measure flat.
They're not horns.
They REQUIRE constant directivity EQ.
Re: Q
Hi Patrick,
Looks like you like the BMS a lot and AJ might have step on your toe. For my 1st compress driver, I would prefer one that is easy to work with and from what I read B&C is not too shabby either. It also have the flexibility to cross at 1.5kHz - a feature I wanted. Coming from dome tweeter I have a lot to learn about compress driver and appreciate your & others who share your experience.
I presume what you mean here is they don't measure flat by themself but when pair with a compress driver, which also don't measure flat by most time, the end result should measure flat.
Hi Patrick,
Looks like you like the BMS a lot and AJ might have step on your toe. For my 1st compress driver, I would prefer one that is easy to work with and from what I read B&C is not too shabby either. It also have the flexibility to cross at 1.5kHz - a feature I wanted. Coming from dome tweeter I have a lot to learn about compress driver and appreciate your & others who share your experience.
Patrick Bateman said:
I presume what you mean here is they don't measure flat by themself but when pair with a compress driver, which also don't measure flat by most time, the end result should measure flat.
Re: Re: Q
I meant what I said -
Compression drivers on waveguides do not measure flat.
They require constant directivity EQ to measure flat.
This is one of the differences between horns and waveguides. There are many more.
A quick google search reveals this:
http://www.peavey.com/support/technotes/soundsystems/horn_eq.cfm
"Every so often I encounter floor salespersons and sound people that do not have an understanding of why compression drivers that are mounted on Constant Directivity high frequency horns require a special form of equalization that permits them to exhibit proper high frequency response. In this article we will explain the need for the high frequency compensation know as CD EQ.
The Peavey 22, 22A, 22T, 22TI, 22XT, RX-22, 44T, and 44XT compression drivers require this form of high frequency equalization when used on our constant directivity high frequency horns, or for that matter, any manufacturers constant directivity high frequency horn.
All high frequency compression drivers perform more efficiently or play louder than their paper cone loudspeaker counterparts. The efficiency of a loudspeaker is measured by driving the loudspeaker with one watt of input power while measuring how loud in sound pressure level (SPL) it will be at a distance of one meter from the loudspeaker enclosure. This is called the One Watt, One Meter Sensitivity rating of the loudspeaker.
At Peavey we measure the constant directivity of the horns Beamwidth, using a TEF analyzer. (TEF stands for Time, Energy, and Frequency). A typical compression driver may have a one watt at one meter sensitivity rating of 110 dB of SPL, while a typical paper cone loudspeaker used for sound reinforcement may exhibit a one watt at one meter sensitivity of 100 dB of SPL.
In order for the two transducers to produce the same acoustic level from a loudspeaker enclosure, the crossover must provide for
-10 dB of Attenuation or reduction (Pad) in the signal level of the high frequencies going to the compression driver."
I hope I don't sound like some kind of a know-it-all;
I used to build tractrix horns, and CD waveguides are a whole different ballgame.
Hope you have fun with this project!
SamL said:
I meant what I said -
Compression drivers on waveguides do not measure flat.
They require constant directivity EQ to measure flat.
This is one of the differences between horns and waveguides. There are many more.
A quick google search reveals this:
http://www.peavey.com/support/technotes/soundsystems/horn_eq.cfm
"Every so often I encounter floor salespersons and sound people that do not have an understanding of why compression drivers that are mounted on Constant Directivity high frequency horns require a special form of equalization that permits them to exhibit proper high frequency response. In this article we will explain the need for the high frequency compensation know as CD EQ.
The Peavey 22, 22A, 22T, 22TI, 22XT, RX-22, 44T, and 44XT compression drivers require this form of high frequency equalization when used on our constant directivity high frequency horns, or for that matter, any manufacturers constant directivity high frequency horn.
All high frequency compression drivers perform more efficiently or play louder than their paper cone loudspeaker counterparts. The efficiency of a loudspeaker is measured by driving the loudspeaker with one watt of input power while measuring how loud in sound pressure level (SPL) it will be at a distance of one meter from the loudspeaker enclosure. This is called the One Watt, One Meter Sensitivity rating of the loudspeaker.
At Peavey we measure the constant directivity of the horns Beamwidth, using a TEF analyzer. (TEF stands for Time, Energy, and Frequency). A typical compression driver may have a one watt at one meter sensitivity rating of 110 dB of SPL, while a typical paper cone loudspeaker used for sound reinforcement may exhibit a one watt at one meter sensitivity of 100 dB of SPL.
In order for the two transducers to produce the same acoustic level from a loudspeaker enclosure, the crossover must provide for
-10 dB of Attenuation or reduction (Pad) in the signal level of the high frequencies going to the compression driver."
I hope I don't sound like some kind of a know-it-all;
I used to build tractrix horns, and CD waveguides are a whole different ballgame.
Hope you have fun with this project!
JoshK said:
It would only be an apples-to-apples comparison if their response was equivalent.
Remember my experience with the JBL that I described in an earlier post?
The JBL sounded better at first because it's unequalized response was superior to the unequalized response of the BMS.
But after a bit of crossover work, the BMS was a better driver for that particular project.
Here's an analogy:
Imagine if you listened to a $25 paper cone woofer without a crossover, and you also listened to a $250 Seas Excel woofer without a crossover. The paper cone woofer is going to sound better, because the Seas Excel woofer has a giant peak in it's upper passband due to ringing.
But once you equalize out that peak, the Excel woofer really shines
Does that make sense?
I have never heard the B&C 250 or the BMS 4540 driver. So this comment is a general one:
All HF compression driver exhibit a 6dB/oct rolloff in reponse above their mass breakup frequency. In most drivers, this breakup occurs at 3-5 kHz - but (as always) different drivers exhibit different behaviour. If flat response is required, then this falling response must be equalised.
In conventional HF horns the directional response narrows with frequency. These are not constant directivity devices. Measured on-axis, this narrowing of HF energy can have the same effect on the frequency response than boosting the HF signal. You might actually say that the horns rising directivity in itself provides a form of EQ - if you measure on axis.
(Of course: Electrical EQ on compression drivers on conventional horns can of course be beneficial, but it is not necessarily a required design criteria. Such horns are meant to be measured (and listened to) mainly on axis.
A waveguide, on the other hand, is a constant directivity (CD) device. The response does not narrow with frequency - in fact it is a design criteria to maintain a constant (wide compared to conventional horns) polar response over a large part of the frequency spectrum. Then EQ'ing becomes a nessesity.
All CD devices (CD here meaning: Constant Directivity) requires eq'ing of the signal - wether they'll be compression drivers, dome tweeters or cone units.
I agree with Mr.Bateman here. Listening to drivers on constant directivity waveguides without CD equalization has IMO limited usefulness.
This is a useful general circuit for passive EQ'ing HF waveguides:
All HF compression driver exhibit a 6dB/oct rolloff in reponse above their mass breakup frequency. In most drivers, this breakup occurs at 3-5 kHz - but (as always) different drivers exhibit different behaviour. If flat response is required, then this falling response must be equalised.
In conventional HF horns the directional response narrows with frequency. These are not constant directivity devices. Measured on-axis, this narrowing of HF energy can have the same effect on the frequency response than boosting the HF signal. You might actually say that the horns rising directivity in itself provides a form of EQ - if you measure on axis.
(Of course: Electrical EQ on compression drivers on conventional horns can of course be beneficial, but it is not necessarily a required design criteria. Such horns are meant to be measured (and listened to) mainly on axis.
A waveguide, on the other hand, is a constant directivity (CD) device. The response does not narrow with frequency - in fact it is a design criteria to maintain a constant (wide compared to conventional horns) polar response over a large part of the frequency spectrum. Then EQ'ing becomes a nessesity.
All CD devices (CD here meaning: Constant Directivity) requires eq'ing of the signal - wether they'll be compression drivers, dome tweeters or cone units.
I agree with Mr.Bateman here. Listening to drivers on constant directivity waveguides without CD equalization has IMO limited usefulness.
This is a useful general circuit for passive EQ'ing HF waveguides:
Attachments
EspenE said:
And I agree also. Any waveguide that does not require EQ is not CD. Which brings up another point - just calling something a waveguide does not make it CD, in fact most that I have measured are not. It takes some work to get things to come out right.
I have measured a lot of compression drivers and I will only use B&C - I really like the DE-250. I compared it to a mega bucks TAD and liked it a lot better. When properly EQ'd the DE-250 can easily go down to 900 Hz. or so.
As to the discussion of waveguides and compression drivers. In theory the waveguide has to be design to match the driver and/or visa-versa. This idea of interchangable drivers is a convenience but its NOT really the right way to do things. What happens is that the driver waveguide combination is hit or miss, but if you think about it probalistically its probably a miss. If the waveguide needs to match the driver to be optimal, what is the chance that a random choice of parts will match up optimally? Just about zero.
If you think that you like compression dirvers on waveguides try listening to one where the waveguide is designed to match the driver, properly EQ'd and with some magic foam added to top things off
The reason that waveguides get such a bad rep is because there are so many way to screw them up. But done right, nothing else even comes close.
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