AudioCircle
Audio/Video Gear and Systems => Open Baffle Speakers => Topic started by: Bumpy on 2 Feb 2019, 11:13 am
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Title says it all.
Particularly interested in anyone that's using DSP for just the low pass filter.
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Hi Bumpy,
Why do you ask?
I'm working on a bi-amped three way system using separate channels for woofer and then mid/tweeter. The high end then uses a passive crossover to split mid and tweeter.
The woofer - mid crossover is a MiniDSP 2x4HD which also provides system EQ and phase alignment.
As it's open baffle, the woofer crossover is a low 150Hz and is currently a 48dB/Oct Linkwitz–Riley configuration.
(https://www.audiocircle.com/image.php?id=189938)
Sorry for the image rotation - no idea why it only happens here.
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Thank you OB
I am running 3 way open baffles. The mid and tweeter are perfect, but the mid runs full range towards the low frequencies, so the low pass on the bass, to get a good crossover, is not straightforward. Equally the open baffle bass generally needs a bit of a boost in volume. The DSP units you mention seems suitable, so I have a couple of further questions.
1. What amplification are you using for the bass.
2. Where are you getting your signal for the DSP unit
Thanks
PS I get a lot of pictures that fall over. Annoying isn't it - this is the only site that does it !!!
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I said before file a bug report. It would help if you uploaded an original image to dropbox and provided a link.
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I said before file a bug report. It would help if you uploaded an original image to dropbox and provided a link.
Sorry John, I foolishly thought once a moderator had commented on it something would be done. This coupled with the fact I couldn't work out how to file a bug report :(
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I too use the MiniDSP as crossover/EQ/DAC/remote volume control. System is (very) loosely based on OBL-15 design – Alpair 12P running wide open and 15PR400 for the bottom. Amps are what I had on the shelf, for the moment - 8wpc tube for the top end and Dayton APA150 for the 15’s.
There’s lots of ideas for improvements but it sounds so good as is… upgrades will come slowly!
Input is from CD player currently but setting up my Mac Mini (headless) to plug into the 2X4HD.
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Using a Berhinger 2496 to feed sub amps. Signal coming from the second output on preamp.
Also utilizing a PLLXO to high pass between the pre and main speaker amps.
All is still in experimental stage but sounding pretty good.
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I too use the MiniDSP as crossover/EQ/DAC/remote volume control. System is (very) loosely based on OBL-15 design – Alpair 12P running wide open and 15PR400 for the bottom. Amps are what I had on the shelf, for the moment - 8wpc tube for the top end and Dayton APA150 for the 15’s.
There’s lots of ideas for improvements but it sounds so good as is… upgrades will come slowly!
Input is from CD player currently but setting up my Mac Mini (headless) to plug into the 2X4HD.
Thanks, for clarity does 100% of you signal pass through the DSP?
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1. What amplification are you using for the bass.
2. Where are you getting your signal for the DSP unit
1) The bass drivers are 4 ohms combined and I have 250WRMS to provide a little head room for normal listening levels. The high(ish) power is required because of the bass slope applied to offset open baffle bass attenuation below the narrow baffles Fc. The slope applied is continuous -5dB/oct, below theory, but about right for my finite room environment.
200Hz = 0dB
100Hz = +5dB
50Hz = +10dB
25Hz = +15dB
Low Cut @ 16Hz / 48dB/Oct
You need a high power driver with a lot of Xmax to handle this. I am tuning the system using a Umik-1 and REW. Overall the result is very pleasing.
2) The MiniDSP 2x4HD has 3 inputs. I'm using USB (with the internal DAC) from a music server and TOSLink from a Chromecast in 192KHz (Premium) mode. The RCA Line input is connected to a CD player. It's very quiet and easy to use.
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1) The bass drivers are 4 ohms combined and I have 250WRMS to provide a little head room for normal listening levels. The high(ish) power is required because of the bass slope applied to offset open baffle bass attenuation below the narrow baffles Fc. The slope applied is continuous -5dB/oct, below theory, but about right for my finite room environment.
200Hz = 0dB
100Hz = +5dB
50Hz = +10dB
25Hz = +15dB
Low Cut @ 16Hz / 48dB/Oct
You need a high power driver with a lot of Xmax to handle this. I am tuning the system using a Umik-1 and REW. Overall the result is very pleasing.
2) The MiniDSP 2x4HD has 3 inputs. I'm using USB (with the internal DAC) from a music server and TOSLink from a Chromecast in 192KHz (Premium) mode. The RCA Line input is connected to a CD player. It's very quiet and easy to use.
Thanks OB, the mini DSP 2x4 seems to do most things well, but if used just as a low pass filter is there scope to change the phase?
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:)
Hello
example:
U-Frame 20 cm speaker 18 " QTS 0.7 / fs 27 Hz // + 10 db at 30 Hz
(https://nsa40.casimages.com/img/2019/02/08/190208014548743278.jpg) (https://www.casimages.com/i/190208014548743278.jpg.html)
U-Frame 45 cm speaker 18 " QTS 0.7 /fs 27 Hz // + 0 db at 30 Hz
(https://nsa40.casimages.com/img/2019/02/08/190208014549279422.jpg) (https://www.casimages.com/i/190208014549279422.jpg.html)
200Hz = 0dB
100Hz = +5dB
50Hz = +10dB
25Hz = +15dB
It is not good to make such a correction, the distortion will be too great and produce a serious bad quality.
For a baffle plane, it is better to choose the right speaker and to adapt its load, the speakers of large diameter
:)
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Thanks Gils
I am not skilled enough to know what those graphs are showing :(
Two of the rules I always remember with DSP are
1. Turning down peaks is better for SQ than turning up dips.
2. Match the speakers as best you can so the DSP has less to do.
I think rule 2 is what you are saying.
My 15" drivers (without DSP) give enough bass for me in the OB when driven with my 1.8W triode amp. I will be using the DSP to divorce the bass drivers from the midrange, to introduce a low pass filter for the bass driver and perhaps turn up the bass just a little :)
I have tested (without DSP) the Rotel amp that is to drive the bass drivers. It has the right characteristics.
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:)
hello
you have to reduce the distortion rate as much as possible, make unnecessary gains only accentuate the distortion and produce a bad low quality, it also generates unnecessary high power to balance the bands.
best regards Gilles
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you have to reduce the distortion rate as much as possible, make unnecessary gains only accentuate the distortion and produce a bad low quality, it also generates unnecessary high power to balance the bands.
Hi gils, in principle I agree but at very low frequencies I have two listening observations:
1) The bass, even with such high boost, is tight, transparent and effortless. Being free of resonance it still has that amazing open baffle feel. Low double bass notes sound like the instrument is in front of you.
2) Distortion below 50Hz is hard to hear. Even synthetically created distortion to 10% is much harder for me to discern that at higher frequencies.
I have A/B listened with various filters and slopes and like the higher boost more.
What I do observe is that the poles and zeros of the bass slope correction filters should be outside the bass speakers functional frequency band to reduce the phase impact.
Below are REW measurements that show the distortion effect of the greater boost. I can hear the impact of the flatter response - I can't hear the extra distortion - mostly listening to jazz and rock.
Bass Boost Distortion +15dB max (15-200Hz)
(https://www.audiocircle.com/image.php?id=190149)
Bass Boost Distortion +10dB max (15-200Hz)
(https://www.audiocircle.com/image.php?id=190150)
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:) hello Openly Baffled,
To reduce this huge distortion, you tried to lengthen the U-Frame?
What is the reference of your bass speaker?
now is good :)
(https://nsa40.casimages.com/img/2019/02/09/190209120439841234.png) (https://www.casimages.com/i/190209120439841234.png.html)
best regards Gilles
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Hi Giles,
I actually dislike the sound generated by a U baffle. I have tried several designs and I can always perceive a "box style" resonance that detracts from the clean open baffle sound.
Pictured below is one of my test set-ups from last year where I experimented with a variable U frame using piano hinges and sides trimmed to various depths from 250mm to 50mm. None of these combinations appealed. The effect of the sides was audible and the main measurement impacted was impulse response.
As I can't hear the distortion, I might repeat my measurements outside in case the "huge" distortion is an artifact of the room and it's contents. There is a lot of vibration in the room during the frequency sweeps.
(https://www.audiocircle.com/image.php?id=190154)
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I understand better, nice job. :)
the idea of only doing bass in U-Frame would be good from 20 hz to 150 Hz, then tuning with low medium or wide band from 150 Hz up to 20 Khz, the short acoustic circuit is less important in Flat- frame.
the agreement of the 18 inches are at 100 Hz see less depending on the speakers used.
For tests, I have tuned my JBL 4311b on the box 2x18 inches U-Frame at 45 Hz, the quality of bass is remarkable in U-Frame.
this is a JBL 4311b recording with a U-Frame subwoofer 45 Hz.
https://drive.google.com/file/d/1ZRb54_dasZrVGI_1l2VWz0Dkrj0-A8b_/view?usp=sharing
best regards Gilles
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I too used temporary side baffles to create a U frame. With the baffle over the full height of the speaker, about 8"deep. I did not like it as some of that lovely OB sound was gone. Now I run with a deeper U baffle but only behind the bass driver. Its 18" (45cm) deep. It has no top but I may experiment with that later.
Here it is during my experimental lash up. NOTE, I abandoned the lid
(https://www.audiocircle.com/image.php?id=190179)
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Hi Bumpy,
Your experience and observations are maybe similar to mine. I also experimented with the lower extended baffle to avoid the midrange coloration.
In the end, using comparison to an actively EQ'd 22" flat baffle, I decided to ditch the extended baffle all together. This included an extended flat baffle that still seemed to cause the loss of purity in the bass (I tried 22" 26" 30" 36" widths at the lower woofer mid-point).
My conclusion, was that any mechanical bass loading to extend the lower end (below 40Hz) was resulting in the loss of sound purity in live double-bass listening. Electronic EQ with the same gain seemed to me to have less impact - so I went with active EQ.
However I agree that it's a continuum and based on your drivers and baffle configuration there may well be excellent mechanical solutions - I just didn't have the patience to find one. I suppose active EQ and Watts were cheaper than time!
Thanks for the "work in progress" photo.
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Hi Bumpy,
Your experience and observations are maybe similar to mine. I also experimented with the lower extended baffle to avoid the midrange coloration.
In the end, using comparison to an actively EQ'd 22" flat baffle, I decided to ditch the extended baffle all together. This included an extended flat baffle that still seemed to cause the loss of purity in the bass (I tried 22" 26" 30" 36" widths at the lower woofer mid-point).
My conclusion, was that any mechanical bass loading to extend the lower end (below 40Hz) was resulting in the loss of sound purity in live double-bass listening. Electronic EQ with the same gain seemed to me to have less impact - so I went with active EQ.
However I agree that it's a continuum and based on your drivers and baffle configuration there may well be excellent mechanical solutions - I just didn't have the patience to find one. I suppose active EQ and Watts were cheaper than time!
Thanks for the "work in progress" photo.
Thanks OB
I am hugely encouraged by the runaway success of my midrange, so I press on.
Equally I note what you say about the extended baffle. You certainly explored the options:) I think once you have discovered the open baffle sound its very recognisable when it is compromised.
Out of interest do you think you speakers get below 40hz now. Mine don't at present. This doesn't concern me but its nice to know what others are getting.
BTW, lovely looking speakers. :thumb: I see that your bass and midrange drivers are closer to each other than mine, so there will be a difference there.
In case you missed it elsewhere here is a slightly more refines version of te side baffles. I have also pulled the speakers further out from the wall.
(https://www.audiocircle.com/image.php?id=190261)
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Hi Bumpy,
I am hugely encouraged by the runaway success of my midrange, so I press on.
Great that you have achieved Open Baffle Nirvana in the midrange. It's certainly a sound that once heard, can never be unheard - so no going back.
Deep bass is always a challenge. Mine can be flat to 20Hz with active equalization and bi-amping - hence my interest in this thread. This is using a 15" and 12" woofer combo.
Below is an REW plot of my speakers - in room - from the discussion with Giles above.
(https://www.audiocircle.com/image.php?id=190149)
Kyron Audio's Gaia achieve 25Hz with no baffles and active equalization... at a price ;)
http://kyronaudio.com.au/gaia.html (http://kyronaudio.com.au/gaia.html)
I would love to hear these in action.
Distance from the wall is important. I find 5-6ft is a good trade-off between sound and practicality. In a hall with 15ft behind them they sound quite different.
Don't be too concerned about bass-mid centre distance. The phase error only appears in sounds reflecting off the floor or ceiling. I think the advantage of raising the mid away from the floor should counter any other negatives.
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Hello,
no correction ;)
(https://zupimages.net/up/18/10/c11f.png)
best regards Gilles
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Hello,
no correction ;)
(https://zupimages.net/up/18/10/c11f.png)
best regards Gilles
Thats great Gilles. Do you have a reference to your system?
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I have been reflecting on my 15" bass drivers which are vintage alnico Altec 416B.
They are what is know as VOTT, meaning 'Voice of the Theatre', and spent their formative years in a theatre or cinema so I guess they are well able to pump out the low frequencies :wink:
Up till now, running in unison with the mid range and tweeter fed by a single amp, they deliver an acceptable level of bass for me, but interestingly I have never really seen the cones move even on heavy bass notes. I am therefore guessing with a separate amp and DSP I may be able to release the genie from the bottle.
(https://www.audiocircle.com/image.php?id=190262)
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Simple question I thought I would slip in here. :)
The picture shows my simple high pass filter on the tweeter. I believe twinning up capacitors like this is done to 'neutralise' magnetic fields, but what is the configuration called. I did know but have forgotten :duh:
(https://www.audiocircle.com/image.php?id=190264)
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Thats great Gilles. Do you have a reference to your system?
this is speaker infraflex 36" :)
(https://nsa40.casimages.com/img/2019/02/10/190210031950787761.png) (https://www.casimages.com/i/190210031950787761.png.html)
best regards Gilles
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I have been reflecting on my 15" bass drivers which are vintage alnico Altec 416B.
They are what is know as VOTT, meaning 'Voice of the Theatre', and spent their formative years in a theatre or cinema so I guess they are well able to pump out the low frequencies :wink:
Up till now, running in unison with the mid range and tweeter fed by a single amp, they deliver an acceptable level of bass for me, but interestingly I have never really seen the cones move even on heavy bass notes. I am therefore guessing with a separate amp and DSP I may be able to release the genie from the bottle.
(https://www.audiocircle.com/image.php?id=190262)
Hello Bumpy,
very good job but the Altec 416 is made for horn speakers, his QTS too low does not allow him to produce bass in open cabinet, he find you a speaker 15 "or 18" low blow (50 €) with a small engine, much like the 15A eminence at high QTS.
best regards Gilles
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Its always an interesting debate around Qts. Many of us, including me, learnt most of what we know from the Lampizator.
Here is how he describes the bass driver with a recommendation for the Altec in the P17 on which mine are based -
Max Fs 37Hz, optimum 25Hz
Min sensitivity 97dB
Max Qts 1 optimum 0.35
The other advantage of the Altecs in my baffles is the voicing marries up beautifully with vintage alnico magnet, paper cones of the mid and tweeter.
I have an open mind on this and if not successful with the Altecs I'm quite prepared to try others.
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I use active servo bass drivers in my setup (GR Research Super 7s). It's nice because it goes to 20hz with tons of power, but is also extremely fast, tight and tuneful. They'll play up to 200hz and thus will mate with just about any "top portion" you care to run. It's nice because it solves the whole bass issue in one elegant package.
Servo drivers in an OB config really is a game changer.
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I use active servo bass drivers in my setup (GR Research Super 7s). It's nice because it goes to 20hz with tons of power, but is also extremely fast, tight and tuneful. They'll play up to 200hz and thus will mate with just about any "top portion" you care to run. It's nice because it solves the whole bass issue in one elegant package.
Servo drivers in an OB config really is a game changer.
Interesting alternative. Do you have a website reference?
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Interesting alternative. Do you have a website reference?
The kits are on the GR Research website here - http://gr-research.com/diysubwooferkits.aspx
And they also have a forum here on AC. The thread that's probably most relevant to check out is the one discussing the H-Frame flat packs, here - https://www.audiocircle.com/index.php?topic=139480.0
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The kits are on the GR Research website here - http://gr-research.com/diysubwooferkits.aspx
And they also have a forum here on AC. The thread that's probably most relevant to check out is the one discussing the H-Frame flat packs, here - https://www.audiocircle.com/index.php?topic=139480.0
Thanks, a good read.
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:D
U-Frame 40 cm for 18" and U-Frame 20 cm for 10" :)
(https://nsa40.casimages.com/img/2019/02/11/190211035810306599.png) (https://www.casimages.com/i/190211035810306599.png.html)
(https://nsa40.casimages.com/img/2019/02/11/190211035809352490.png) (https://www.casimages.com/i/190211035809352490.png.html)
https://drive.google.com/file/d/1KPzI9mvwnelNzvyA72NHTrWvbKpsAgf5/view?usp=sharing
best regards Gilles
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Its always an interesting debate around Qts. Many of us, including me, learnt most of what we know from the Lampizator.
Here is how he describes the bass driver with a recommendation for the Altec in the P17 on which mine are based -
Max Fs 37Hz, optimum 25Hz
Min sensitivity 97dB
Max Qts 1 optimum 0.35
The other advantage of the Altecs in my baffles is the voicing marries up beautifully with vintage alnico magnet, paper cones of the mid and tweeter.
I have an open mind on this and if not successful with the Altecs I'm quite prepared to try others.
I have Googled and read quite a lot of stuff on the relative merits of high and low Qts.
This is my easiest to understand definition.
Qts: The Qts is the total damping which is the combination of mechanical and electromechanical damping. The higher the number = the drivers inability to come to rest after the electrical signal has ceased.
So in the context of our bass drivers, high Qts means the driver is more 'springy' and able to respond better to the signal hence better (easier) low bass, but that comes at the expense of poorer control which must impact on SQ.
Low Qts can be selected for more control of the driver hence improved SQ. But the driver is more damped and low bass is more difficult to achieve easily. I would welcome your response.
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I would welcome your response.
I agree with your observations and definition.
The "Q" of a second order system is a simple measure of resonant damping. Q < 0.7 is overdamped and less resonant, Q > 0.7 is underdamped and more resonant.
High Qts driver are used in open baffle to increase bass near the drivers Fs. I believe this comes at the cost of ringing and poor impulse response.
My obs and listening tests lead me to the conclusion that high Qts is undesirable unless the system needs to be passive.
Active systems can tolerate low Qts drivers and give better performance but require more power and more EQ.
I personally went for a Qts just under 0.7 in an attempt to get good impulse response with minimal EQ. The result seems to be tight, deep and "effortless" bass. The majority of GR Research's excellent servo subs also have Qts near 0.7 with one notable exception.
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hello,
impulse reponse bad ? :nono:
look :D
(https://nsa40.casimages.com/img/2019/02/11/19021108160081084.png) (https://www.casimages.com/i/19021108160081084.png.html)
best regards Gilles
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I agree with your observations and definition.
The "Q" of a second order system is a simple measure of resonant damping. Q < 0.7 is overdamped and less resonant, Q > 0.7 is underdamped and more resonant.
High Qts driver are used in open baffle to increase bass near the drivers Fs. I believe this comes at the cost of ringing and poor impulse response.
My obs and listening tests lead me to the conclusion that high Qts is undesirable unless the system needs to be passive.
Active systems can tolerate low Qts drivers and give better performance but require more power and more EQ.
I personally went for a Qts just under 0.7 in an attempt to get good impulse response with minimal EQ. The result seems to be tight, deep and "effortless" bass. The majority of GR Research's excellent servo subs also have Qts near 0.7 with one notable exception.
You can't just look at a drivers Qts and conclude how it will perform in an OB system,
While a high Qts (1.0 to 1.5) woofer will ring in a box when placed in an OB the low end will be rolled off and the resulting combined SPL response will be flat and then roll off to eventually become an 18 dB/octave slope. You can adjust the depth and shape of the bass response by changing the size of the baffle and the position of the woofer.
If you place a lower Qts (< 0.5) woofer in an OB speaker the low end will be very weak until you add some low frequency boost/EQ to raise the low frequency output producing a flat SPL response that will also eventually roll off at 18 dB/octave.
If the low and high Qts OB speaker systems exhibit similar low frequency responses then the woofer cone's are behaving in a similar manner. The low Qts woofer with EQ added will produce the same infinite baffle response shape as the high Qts woofer, both may ring.
Assuming the goal for OB bass is the same the performance should also be reasonably close if you get their with a low Qts or high Qts woofer. A simple, inexpensive, and passive option is only achieved with a high Qts woofer without any sonic problems if the designer knows what they are doing. A low Qts woofer traditionally used in a box speaker will probably be more expensive due to the bigger/stronger motor, require EQ which means an active set up, which means a second amp adding more cost and complexity. Both approaches can work well, pick your trade-offs.
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While a high Qts (1.0 to 1.5) woofer will ring in a box when placed in an OB the low end will be rolled off and the resulting combined SPL response will be flat and then roll off to eventually become an 18 dB/octave slope. You can adjust the depth and shape of the bass response by changing the size of the baffle and the position of the woofer.
I agree in part. My understanding is…
Qts is derived from Qms which is a measurement of mechanical damping at resonance in an infinite baffle configuration. This is very similar to the mechanical behavior exhibited in an open baffle speaker which is related to infinite baffle when the woofer is mounted on a solid board..
The reason that most systems using high Qts drivers don’t exhibit a rise in their bass response, is because Fs is below the baffle cut-off frequency and therefore the “bump” at Fs is subject to a -6db/oct baffle slope.
However, the resonance at Fs is still occurring and results in the desired bass boost that some Open Baffle designers are after. BUT, the boost is only a result of resonance and this can be heard as a bass artifact and impacts the impulse response due to ringing.
From a basic physics point of view there is no free lunch. The bass boost is only a result of resonance and the ringing in the time domain is convolved to product a response gain a in the frequency domain.
It's not altogether a bad thing - getting bass where otherwise there would be very little is certainly a plus for a passive speaker.
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However, the resonance at Fs is still occurring and results in the desired bass boost that some Open Baffle designers are after. BUT, the boost is only a result of resonance and this can be heard as a bass artifact and impacts the impulse response due to ringing.
I don't agree with that at all. There is no ringing in a well designed OB with a high Qts woofer.
So you don't think that a low Qts woofer with EQ applied, to selectively boost the lowest frequencies and counteract the 6 dB/octave roll-off due to the baffle, does not exhibit the same resonant behavior as a high Qts woofer if you tune the systems to produce the same low frequency SPL response.
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Hello
Listen to the difference between the original and my copy with the cabinet open baffle, there is a problem mainly in the low medium "ringring" there is other but less important.
the bass 18 "is low 30Hz to 80Hz and the medium 10" 80Hz to 2KHz, the compression over the spectrum up to 18Khz.
the Altec 416 of very good quality could be tuned from 80 Hz to 2 Khz and use a loudspeaker for bass with high QTS to reproduce the bass.
I will try to find a good quality speaker in 10 " whatever his QTS, there I think will be the right solution, the pickups when taking his sound were 2 m from the speaker.
https://drive.google.com/file/d/1dGagEpdXyg491T1y_84s49_mi5BkWcqD/view?usp=sharing
original version
https://youtu.be/_agnoIXNc3w
best regards
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The Altec 416 of very good quality could be tuned from 80 Hz to 2 Khz and use a loudspeaker for bass with high QTS to reproduce the bass.
I will try to find a good quality speaker in 10 " whatever his QTS, there I think will be the right solution, the pickups when taking his sound were 2 m from the speaker.
Thanks for the advice Gilles, but this wont work for me. My mid range driver works beautifully down to about 100Hz and has the added sonic benefit that it does not require a crossover. So I would just need a quality sub up to 100Hz. I will give the Altec 416 a go with DSP.
If that fails, this driver has caught my eye.
http://www.pureaudioproject.com/product/15inch-open-baffle-bass-woofers/ (http://www.pureaudioproject.com/product/15inch-open-baffle-bass-woofers/)
(https://www.tnt-audio.com/jpg/pure_audio_driver.jpg)
Or this
https://www.lean-business.co.uk/eshop/faitalpro-15pr400-8ohm-15-400watt-pa-speaker-p-1381.html (https://www.lean-business.co.uk/eshop/faitalpro-15pr400-8ohm-15-400watt-pa-speaker-p-1381.html)
(https://www.lean-business.co.uk/eshop/images/FAITALPRO%2015PR400%20single.gif)
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Or this
https://www.lean-business.co.uk/eshop/faitalpro-15pr400-8ohm-15-400watt-pa-speaker-p-1381.html (https://www.lean-business.co.uk/eshop/faitalpro-15pr400-8ohm-15-400watt-pa-speaker-p-1381.html)
(https://www.lean-business.co.uk/eshop/images/FAITALPRO%2015PR400%20single.gif)
Study the Troels Graveson site for his OBL-11 and OBL-15 designs. The OBL-15 uses the 15PF400 driver and the crossover components are listed.
gab
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Thanks Gab for the link. At about 100Hz I suspect I will be crossing a lot lower than Troels
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Does anyone have any views on which driver is best up to say 120hz?
I am gravitating towards the Pure Audio which was optimised for open baffle
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Does anyone have any views on which driver is best up to say 120hz?
I am gravitating towards the Pure Audio which was optimised for open baffle
Honestly, I'd love to get my hands on a pair of Altec 416's. I think you should definitely give the DSP option a try before moving on to another bass driver. Even a dedicated plate amp w/xo should do the trick (you can opt for built-in boost around 25Hz if you like)
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:D
https://www.ebay.fr/itm/2-haut-parleurs-ALTEC-416-16B-ALNICO-/202572381319?_trksid=p2385738.m4383.l4275.c10
best regards
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:thumb:
My infraflex + Altec 416 (VOTT) ;)
(https://nsa39.casimages.com/img/2018/05/28/180528122321704644.png)
(https://nsa39.casimages.com/img/2018/05/28/180528122339592649.png)
(https://nsa39.casimages.com/img/2018/05/28/180528122434763398.png)
(https://nsa40.casimages.com/img/2019/02/15/190215115343231828.png) (https://www.casimages.com/i/190215115343231828.png.html)
best regards
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:D
https://www.ebay.fr/itm/2-haut-parleurs-ALTEC-416-16B-ALNICO-/202572381319?_trksid=p2385738.m4383.l4275.c10
best regards
I think those are 16 ohms. The 8 ohm version is a bit rarer.
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:scratch:
hello,
I listened to Altec 416 8b, it's a fairly common HP, why this obsolete HP not found?
http://www.loudspeakerdatabase.com/search/14.0_size_in_15.0/4_z_8/95.0_spl_118.0/8_fs_35/0.30_qts_0.70
best regards Gilles
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I use a wyred4sound mpre with its dual outputs....one set goes to an amp that drives a passive crossover-based "upper" section (the top part of GR Research's Super Vj....a 2-way coaxial) and the other set goes to an iNuke for powering my bass speakerss (sealed kit based on the Dayton Audio 12" Reference Series driver).
The upper sections rolls in at ~190hz and the lower section covers 20hz to 190hz. I use the DSP of the iNuke to room correct the bass response....and with only 1.3ms added delay, it really blends seemlessly with the upper section.
I really love the setup.
-Jim
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I use a wyred4sound mpre with its dual outputs....one set goes to an amp that drives a passive crossover-based "upper" section (the top part of GR Research's Super Vj....a 2-way coaxial) and the other set goes to an iNuke for powering my bass speakerss (sealed kit based on the Dayton Audio 12" Reference Series driver).
The upper sections rolls in at ~190hz and the lower section covers 20hz to 190hz. I use the DSP of the iNuke to room correct the bass response....and with only 1.3ms added delay, it really blends seemlessly with the upper section.
I really love the setup.
-Jim
Thanks for sharing Jim. You are 'lucky' enough to have a preamp with dual RCA outputs - nice feature.
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Any preamp can drive a main amp and a sub amp - you just need a good quality Y-spitter.
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Thanks for sharing Jim. You are 'lucky' enough to have a preamp with dual RCA outputs - nice feature.
Yeah, its a great preamp. It has a pair of balanced AND unbalanced outputs!
-Jim
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I use a Crown XLS 1502 with its built in crossover to power my AE TD15M 15" drivers. Sounds good to me and worth the trade off and nerdy hassle of trying to formulate a traditional crossover.
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I am using passive XO in mid/high coaxial driver. Bass/mid XO is active, with 2x4HD. Amplifier: Denon AV amp, modified to separate pre-out from main amp inputs. Something like 100W/ch. MiniDSP provides the XO and baffle EQ for all channels. Also moderate room EQ.
Bass unit has 20cm U-frame, but mid is in open baffle area.
https://www.audiocircle.com/index.php?topic=121548.msg1687771#msg1687771 (https://www.audiocircle.com/index.php?topic=121548.msg1687771#msg1687771)
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I use a Crown XLS 1502 with its built in crossover to power my AE TD15M 15" drivers. Sounds good to me and worth the trade off and nerdy hassle of trying to formulate a traditional crossover.
Does it have a fan?
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BTW, the GR Research Super 7 kit with active bass already built out for you is now shipping. Check out the GR Research circle here on AC. In addition, I see that Spatial Audio just announced the X3 and X5, both of which will have active bass sections.
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Does it have a fan?
I believe that my two Crowns have fans but I've never heard them probably because I don't push them very hard. I use one for my 15'" woofs and the other for a pair of folded horn subs. My tweets run off of Heathkit monoblocks or small digital amp with a pair of Fostex transformer attenuators and with no crossovers.
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I am working on a Pass SLOB (Slot Loaded Open Baffle) with a 15" Eminence driver on the bottom and a Cube Audio FC8 full range driver on the top. Jeff McCabe will build the cabinets for me. The X-Over will be built into a DIY preamp using PC boards from DIYAudio, and Pass's LxMini and NuTube circuits. The NuTube will provide the gain, volume and balance controls and input selector switching. The LXMini will provide the crossover and EQ, based on Pass's experiments at his studio in Sea Ranch, CA. Level setting between the upper and lower amps will be accomplished using pink noise, an iPhone hosted RTM app, and the Studio Six Digital iTestMic2.
Amplifiers: Low pass: Aleph 5 (90 watts) and DIY First Watt F5 Turbo V2 (140 watts). High pass: First Watt J2 (25 watts), DIY Pass / Sony VFET (15 watts), and an Elekit TU-8600 (9 300B watts).
Here's some pics:
(https://www.audiocircle.com/image.php?id=198711)
(https://www.audiocircle.com/image.php?id=198712)
(https://www.audiocircle.com/image.php?id=198713)
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As Tyson mentioned several months ago in this thread, the Spatial Audio X-3 has now hit the streets. This is a fantastic OB speaker with powered 15" woofer onboard. If anyone is looking for something like that, I highly recommend it.
Shakey
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Using the 12" Rythmik Audio and GR-Research servo subs in an open baffle H-Frame with DSP crossover using the Danville Signal dspMusik 2x8 system. Low pass with an 8 pole L-R. Also using timedelay to correct for distance offset between the planars and subs baffles.
(https://www.audiocircle.com/image.php?id=198730)
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Using the 12" Rythmik Audio and GR-Research servo subs in an open baffle H-Frame with DSP crossover using the Danville Signal dspMusik 2x8 system. Low pass with an 8 pole L-R. Also using timedelay to correct for distance offset between the planars and subs baffles.
(https://www.audiocircle.com/image.php?id=198730)
Nice! Yeah, the GR Research OB servo sub setup really is the very best bass system in the world at the moment. And yes, I've heard most/all of the top high end stuff.
I gotta get over to your place someday & hear your fully active setup.
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Sounds good.
If you go to RMAF2020, will have a room with the setup to listen to. :)