I’d like to contribute to the thread topic in some way.
LewinskiH01 and I have crossed paths several times in various OB threads. I get the feeling he has more experience especially with the DSP manipulation aspect which I just really hate dealing with.
I hope I am talking about the same thing as others when we bring the subject of mid-bass up.
A Google will tell you that mid-bass generally refers to a frequency range around 70-300Hz. I’m sure we could argue about that, but lets say it’s a reasonable statement?
When I put on my favorite Radiohead album OK Computer and say that I am immediately disappointed in the lack of energy the kick drum has I assume it falls into the mid-bass category.
Another Google will tell you the majority of the energy a kick drum has should be focused in the 40-100Hz range. Again, we can argue. Let’s just run with these assumptions. We know sound is a complex thing.
In actuality, my disappointing kick drum seems to have most of it’s energy planted towards the bottom of the assumed mid bass region…and is clearly also dependent on good bass reproduction in general.
I ask myself where is the “impact” I’m missing out on? Is it a matter of not covering a certain frequency range? Is it an imbalance?
Scratching my head I start looking over the measurements I’ve taken.
I’d like to share some of the measurements I took while I was trying to see if it was possible to get decent sound out of this “experiment” or whatever it is at this point.
I am only doing the basics here and even had to reread the setup instructions off the MiniDSP site for my UMIK-1 and REW.
These are in room measurements taken from the listening position on the top of a chair where my head would be about 11 feet from the speakers. The speakers are about 6.5 feet apart and toed in slightly. There is a drop ceiling just over 7 feet high. It is a large irregular “L” shaped basement room with the main area the speakers are in being about 22 feet by 12.5 feet. Lots of irregular shaped crap around the perimeter of the room like cardboard boxes, cabinets etc.
I calibrated the mic with its file and set levels to about 75 dB. The measurements are not gated. They are 1/12 smoothed.
Here is my SLOB bass panel raw. Meaning no crossover hooked up.
Here is the 108ez raw…no crossover.
Here is an overlay of the raw measurements.
My first observation was that there seems to be a lot of energy from both sources in the 200-400Hz range. There are obviously other problems with peaks and valleys…some ugliness at the top end for sure.
When I first hooked up the B5 crossover and decided to “wing it” I set the high pass filter for the horn at 300Hz 6dB per octave and the low pass for the bass panel at 200Hz 12dB per octave.
With no other adjustment it obviously sounded horrible. Even as I started to try matching the levels by turning up the bass gain and cutting the level if the horns it sounded “honky”. The sound was similar to someone yelling through cupped hands.
After taking some measurements I started trying my best to get a response that would gradually slope off towards the high end.
I left the 108ez high pass at 300Hz but I ended up cutting them by 15dB. Here is a before and after overlay with the raw measurement.
The B5 has an EQ provision to give a boost at 20Hz. I maxed it out along with the bass gain level adjustment. I set the low pass for 100 Hz. The default slope is 12dB per octave as I understand it. Here is an overlay with the raw measurement.
Here is an overlay with both raw measurements and a measurement of the entire system after the crossover adjustments (in gold).
So initially my inexperienced eye said this didn’t look bad considering what I was dealing with.
After reading some comments in the thread and considering the graphs some more I thought perhaps I gave up too much in the 200-400Hz range.
I decided to try and cut the 108ez in the horns steeper with the 12dB per octave slope. I’m still limited to 300Hz as the highest point.
I also tried crossing the bass panel a little higher at 140Hz.
This may have slightly increased the energy in the 200-400Hz area. It did not make a difference to how the kick drum sounded.
It’s funny that to my eyes it looks like it should sound better.
However, as Mr. Cowan said in so many words “There’s no replacement for displacement”. I guess you simply need to move air to create bass (or mid bass)?
LewinskiH01 and I have crossed paths several times in various OB threads. I get the feeling he has more experience especially with the DSP manipulation aspect which I just really hate dealing with.
I hope I am talking about the same thing as others when we bring the subject of mid-bass up.
A Google will tell you that mid-bass generally refers to a frequency range around 70-300Hz. I’m sure we could argue about that, but lets say it’s a reasonable statement?
When I put on my favorite Radiohead album OK Computer and say that I am immediately disappointed in the lack of energy the kick drum has I assume it falls into the mid-bass category.
Another Google will tell you the majority of the energy a kick drum has should be focused in the 40-100Hz range. Again, we can argue. Let’s just run with these assumptions. We know sound is a complex thing.
In actuality, my disappointing kick drum seems to have most of it’s energy planted towards the bottom of the assumed mid bass region…and is clearly also dependent on good bass reproduction in general.
I ask myself where is the “impact” I’m missing out on? Is it a matter of not covering a certain frequency range? Is it an imbalance?
Scratching my head I start looking over the measurements I’ve taken.
I’d like to share some of the measurements I took while I was trying to see if it was possible to get decent sound out of this “experiment” or whatever it is at this point.
I am only doing the basics here and even had to reread the setup instructions off the MiniDSP site for my UMIK-1 and REW.
These are in room measurements taken from the listening position on the top of a chair where my head would be about 11 feet from the speakers. The speakers are about 6.5 feet apart and toed in slightly. There is a drop ceiling just over 7 feet high. It is a large irregular “L” shaped basement room with the main area the speakers are in being about 22 feet by 12.5 feet. Lots of irregular shaped crap around the perimeter of the room like cardboard boxes, cabinets etc.
I calibrated the mic with its file and set levels to about 75 dB. The measurements are not gated. They are 1/12 smoothed.
Here is my SLOB bass panel raw. Meaning no crossover hooked up.
Here is the 108ez raw…no crossover.
Here is an overlay of the raw measurements.
My first observation was that there seems to be a lot of energy from both sources in the 200-400Hz range. There are obviously other problems with peaks and valleys…some ugliness at the top end for sure.
When I first hooked up the B5 crossover and decided to “wing it” I set the high pass filter for the horn at 300Hz 6dB per octave and the low pass for the bass panel at 200Hz 12dB per octave.
With no other adjustment it obviously sounded horrible. Even as I started to try matching the levels by turning up the bass gain and cutting the level if the horns it sounded “honky”. The sound was similar to someone yelling through cupped hands.
After taking some measurements I started trying my best to get a response that would gradually slope off towards the high end.
I left the 108ez high pass at 300Hz but I ended up cutting them by 15dB. Here is a before and after overlay with the raw measurement.
The B5 has an EQ provision to give a boost at 20Hz. I maxed it out along with the bass gain level adjustment. I set the low pass for 100 Hz. The default slope is 12dB per octave as I understand it. Here is an overlay with the raw measurement.
Here is an overlay with both raw measurements and a measurement of the entire system after the crossover adjustments (in gold).
So initially my inexperienced eye said this didn’t look bad considering what I was dealing with.
After reading some comments in the thread and considering the graphs some more I thought perhaps I gave up too much in the 200-400Hz range.
I decided to try and cut the 108ez in the horns steeper with the 12dB per octave slope. I’m still limited to 300Hz as the highest point.
I also tried crossing the bass panel a little higher at 140Hz.
This may have slightly increased the energy in the 200-400Hz area. It did not make a difference to how the kick drum sounded.
It’s funny that to my eyes it looks like it should sound better.
However, as Mr. Cowan said in so many words “There’s no replacement for displacement”. I guess you simply need to move air to create bass (or mid bass)?
Close, 😉 60 - 250 Hz. There's been numerous charts over the decades, but I continue to wish 'we' standardized on this popular one from way back when mid-bass was simply 'bass' and its original legend replaced with an interactive one: https://alexiy.nl/eq_chart/
Not so close 😒, 50 - 550 Hz, so depends on how you choose to divide it up if forced to (note instrument data), which according to my understanding of the pioneer's way is to use the acoustic power mean = ~ (50*550)^0.5 = 166 Hz XO point, then size the drivers based on their desired BW to maintain the summed polar response as if from a single source.
@chromenuts Is there a way for you to expand the vertical scale on those plots? I'm finding it really hard to judge how big the variations are. (I'm much more alert to this issue since I read this AudioXpress article a few months ago: https://audioxpress.com/article/spl-graph-data-let-s-get-back-to-a-level-playing-field)
I’m sure there is. Unfortunately, I’m a complete novice and was lucky to just get through the basic measurement process.
I have the REW software on an old HP laptop running Vista.
It was a hassle just to get an image to post. I had to snip them from the software, save them and then email them to myself because the browser is so outdated that I couldn’t post them properly on the forum.
I have the REW software on an old HP laptop running Vista.
It was a hassle just to get an image to post. I had to snip them from the software, save them and then email them to myself because the browser is so outdated that I couldn’t post them properly on the forum.
I’m not one to just give up on something and move on…but things aren’t looking good.
I’ve been looking for alternative 8” drivers with a higher xmax that would move some more air.
Unfortunately, it’s looking like I built myself into a corner with these panels.
I made the chambers in the slot just big enough to mount the Peerless drivers which have an external diameter of about 205mm.
There is a GRS 8PR-8 driver at Parts Express that would fit, but it doesn’t look like it would make much if any improvement over the Peerless with it’s 3mm of xmax and lower sensitivity.
There is also the GRS 8SW-4 which has about 3X the xmax at 6mm and is still reasonably sensitive at 89dB. However, the frame is 209mm and I made a template to test and see if I could squeeze it in the chamber…it’s a no go.
I’ve been looking to see if I can find anything else. A few MCM divers listed at Newark.
No idea how accurate the data is or if they are worth even trying.
This one says it has 4.25mm xmax, 91dB sensitivity and is good from 40Hz?
https://www.newark.com/multicomp-pr...MIvpaesrz_iAMVjkf_AR13NzyZEAQYHSABEgIVHPD_BwE
If anyone else has any ideas I’m open to suggestions…otherwise these panels may have officially transformed into scrap.
I’ve been looking for alternative 8” drivers with a higher xmax that would move some more air.
Unfortunately, it’s looking like I built myself into a corner with these panels.
I made the chambers in the slot just big enough to mount the Peerless drivers which have an external diameter of about 205mm.
There is a GRS 8PR-8 driver at Parts Express that would fit, but it doesn’t look like it would make much if any improvement over the Peerless with it’s 3mm of xmax and lower sensitivity.
There is also the GRS 8SW-4 which has about 3X the xmax at 6mm and is still reasonably sensitive at 89dB. However, the frame is 209mm and I made a template to test and see if I could squeeze it in the chamber…it’s a no go.
I’ve been looking to see if I can find anything else. A few MCM divers listed at Newark.
No idea how accurate the data is or if they are worth even trying.
This one says it has 4.25mm xmax, 91dB sensitivity and is good from 40Hz?
https://www.newark.com/multicomp-pr...MIvpaesrz_iAMVjkf_AR13NzyZEAQYHSABEgIVHPD_BwE
If anyone else has any ideas I’m open to suggestions…otherwise these panels may have officially transformed into scrap.
So many expensive "high-end" speaker systems completely fail when trying to deliver the punch-you-in-the-chest kick-drum, the type of kick that will knock out a dental filling. Companies keep adding more and more large woofers and more amplification for this purpose, and I don't know why 😳
Are you willing to share more info on this bass system? I don’t have 8 x 15” woofers, but I do have 8 x AE Dipole 12 woofers . . .
The horns may have evolved. I think this is pretty much the final version I heard.
Discussion, links of Bill’s various adventures etc here…
P.S. I’ve got (4) AE Dipole 18 and (2) AE Dipole 15 that Rob was nice enough to sell on to me. Wish I had (2) more of the 15s.
Yeah…all laminated up Baltic Birch that is cut via the in house CNC. Can’t imagine how heavy. The wings are actually adjustable. They have quite the playshop.
There are a few more photos in the A For Ara IG feed, probably FB, too.
Thanks William, I will take a look. Are you able to say any more about the configuration / arrangement of the woofers?
It's a simple minimum volume manifold. The chambers are about as tight as you can make them to push wl/4 resonances out of the passband. You should be able to find some piccies that show. With the stack lam I didn't need clearance to get the drivers out of the holes. The centre section comes apart in four or five pieces.