If you're building a three way, I would also recommend a bigger bass driver, like the CSX 10". Although the 8" is a very good mid/bass. Not exactly bass-shy, if you ask me.
At home I have missions 774. Good speakers, but not exactly known for their deep bass. The specs say they have an f3 of about 35Hz.
Still my DIY speakers with two HDS 182 as mid/woofer go much deeper... I've never measured them, but I sure can hear the difference.
At home I have missions 774. Good speakers, but not exactly known for their deep bass. The specs say they have an f3 of about 35Hz.
Still my DIY speakers with two HDS 182 as mid/woofer go much deeper... I've never measured them, but I sure can hear the difference.
Hi, Peter
Mmm, two 146s? (wicked smile) They're about the same price as the 8" 490s so it's worth a consideration.
I pretty sure 2 x 8" should do it. I just have some problem getting a good model out of those Peerless 8" units with WinISD or Unibox.
Id someone can show me how to get a decent F3 from the 136 or the 490 I'll be forever grateful.
Mos
Mmm, two 146s? (wicked smile) They're about the same price as the 8" 490s so it's worth a consideration.
I pretty sure 2 x 8" should do it. I just have some problem getting a good model out of those Peerless 8" units with WinISD or Unibox.
Id someone can show me how to get a decent F3 from the 136 or the 490 I'll be forever grateful.
Mos
2 x 146s in a 100L box tuned to 22hz gives me an F3 of 57hz and a really good looking phase and group delay curve.
2x 146s in a 100l - although does result in a low f3, specs do not equate to sound quality.
WinISD suggest about 180l for 2 drivers, so youre box is almost half that.
If you want a 100l box then use either 1 driver only vented or go 2 sealed.
Ive always found vented boxes sound better using a larger volume than recommended, tune a bit lower than fs to get more extension.
I've got some research somewhere on the Q of systems & it was quite interesting in that the standard alignments for box volume were on the small side, larger vented boxes came up sounding better. As for sealed it was a bit more subjective with higher Qtc being more popular with the average listner & modern music, lower Qtc were preferred by 'audiophiles' or classical music listeners.
Martin Colloms was mentioned in the research as well.
WinISD suggest about 180l for 2 drivers, so youre box is almost half that.
If you want a 100l box then use either 1 driver only vented or go 2 sealed.
Ive always found vented boxes sound better using a larger volume than recommended, tune a bit lower than fs to get more extension.
I've got some research somewhere on the Q of systems & it was quite interesting in that the standard alignments for box volume were on the small side, larger vented boxes came up sounding better. As for sealed it was a bit more subjective with higher Qtc being more popular with the average listner & modern music, lower Qtc were preferred by 'audiophiles' or classical music listeners.
Martin Colloms was mentioned in the research as well.
Well, that's interesting.
My original plans for a 3 way were for 2 x Vifa P21 8", FS=26.
WinISD defaulted to a 127L box and an F3 and FB of 28hz.
I pushed it down to 85 litres, left the tuning alone and got an F3 of 34hz.
You're saying this can't sound good? I was always under the impression that well designed drivers allowed this sort of tinkering while maintaining good output.
Mos
NB: the other option was to go with the Vifa M22 which (x2) gives an F3 of 34hz in a box of only 56L.
My original plans for a 3 way were for 2 x Vifa P21 8", FS=26.
WinISD defaulted to a 127L box and an F3 and FB of 28hz.
I pushed it down to 85 litres, left the tuning alone and got an F3 of 34hz.
You're saying this can't sound good? I was always under the impression that well designed drivers allowed this sort of tinkering while maintaining good output.
Mos
NB: the other option was to go with the Vifa M22 which (x2) gives an F3 of 34hz in a box of only 56L.
Peerless 850136 in a 60litre, tuned to below what the data sheet reccomends, and PRAY for some room gain... lol
Mos Fetish said:
No... I'm saying put it in a 60litre ported are utilise the room gain... (assuming there is some) Thats what I am doing... the data sheet reccomends like 45Hz as the tuning frequency, I am tuning to something like 35... (don't have winisd with me, and can't remember the exact frequency...) 🙂
"You're saying this can't sound good? I was always under the impression that well designed drivers allowed this sort of tinkering while maintaining good output."
Just saying for vented boxes I prefer using higher volumes with lower tuning - sounds more 'musical' to me. Overall I generally prefer sealed.
As for the M22 I think its a great basss driver, for my system (currently still building) I'm using a pair of M18wo per side, excellent bass for an inexpensive driver.
I would stop & re-assess your intended Vb, SPL, & desired F3. Then pick a driver to suit, there are so many out there it's easy to lose focus.
Just saying for vented boxes I prefer using higher volumes with lower tuning - sounds more 'musical' to me. Overall I generally prefer sealed.
As for the M22 I think its a great basss driver, for my system (currently still building) I'm using a pair of M18wo per side, excellent bass for an inexpensive driver.
I would stop & re-assess your intended Vb, SPL, & desired F3. Then pick a driver to suit, there are so many out there it's easy to lose focus.
Ok. That's why I originally started this whole journey with the P21s. They suited my application. Hoever, I thought the Peerless units might offer better quality as opposed to just suitable parameters.
I may stick with the P21s as they seem pretty forgiving and easy to work with AND they won't sound awful, that must be a given.
I'd like to use the M22s but they seem just a bit too pricey considering I'm buying four of them.
Mos
I may stick with the P21s as they seem pretty forgiving and easy to work with AND they won't sound awful, that must be a given.
I'd like to use the M22s but they seem just a bit too pricey considering I'm buying four of them.
Mos
Really?
What are the parameters of those subs? It seems like you can mess around with Vbs and F3s on the P21s and they just keep on giving a good curve.
Mos
What are the parameters of those subs? It seems like you can mess around with Vbs and F3s on the P21s and they just keep on giving a good curve.
Mos
Yeah they are very forgiving.
These particualr ones were from a Dali isobarik sealed sub. The P21wo-20-08 (from memory) fs=30hz, s=90db.
My subs (2 of them) are about 1200h x 280w x 300d, single fold ie down then up, lightly stuffed with poly/wool.
Really smooth output, good down to at least 30hz, great for music.
These particualr ones were from a Dali isobarik sealed sub. The P21wo-20-08 (from memory) fs=30hz, s=90db.
My subs (2 of them) are about 1200h x 280w x 300d, single fold ie down then up, lightly stuffed with poly/wool.
Really smooth output, good down to at least 30hz, great for music.
I'll be using the P21WO-39-08 but I assume it's the same basic driver. My F3 in an 85 litre box was something like 36hz at a Fb of 26hz--the P21s FS.
As per the rest of this topic, I'm not so much after low, low bass, just something I can model easily and work with. The Peerless units, I think, may be higher quality, but they just don't seem to be that easy to get a good curve out of, at least not by me. I may still use them if I can get some experienced feedback from a few emails I've sent out. The best solution for the Peerless HDS 850146 seems to be a 60L cabinet and a 40hz F3 and FB, but it bugs me that that curve looks a little wacked in WinISD or Unibox.
The P21s may be best for my confidence levels.
Mos
As per the rest of this topic, I'm not so much after low, low bass, just something I can model easily and work with. The Peerless units, I think, may be higher quality, but they just don't seem to be that easy to get a good curve out of, at least not by me. I may still use them if I can get some experienced feedback from a few emails I've sent out. The best solution for the Peerless HDS 850146 seems to be a 60L cabinet and a 40hz F3 and FB, but it bugs me that that curve looks a little wacked in WinISD or Unibox.
The P21s may be best for my confidence levels.
Mos
Mos Fetish said:
It might be good for your confidence level. I wouldn't use it if I had the chance to use Peerless woofers.
A) The Peerless CSX and HDS line have an aluminum short circuiting ring. The Vifa does not mention it, and if the Vifa had it, they would tell you. In a sealed box it makes no difference, but in a ported box, speakers without a short circuiting ring, (Faraday ring) will, when the frequency of resonance is approached, actually travel all the way in or all the way out to the end of their excursion, and then move back and forth from there! This is called suck-in, (or suck-out), and I have observed it happening.
People who are trying to discuss this phenomenon frequently refer to it as "high harmonic distortion", which is true. But to bring home the sense of urgency here, the speaker has high harmonic distortion because it is chopping off one half of the waveform!
To put it bluntly-if you are going to build a vented box, and you have a chance to get a woofer with a short circuiting ring, get it. Unless the Thiele-Small specs disqualify it.
B) The 8's you are talking about require more volume to go low than the Peerless CSX 10". If this is a three way, which means you are going to cross over fairly low, then why are you building just as big a box to put an 8" when you can put that monster 10" in? The Peerless CSX 10" moves almost 3 times as much air as either 8", which translates into 8 or 9 dB at any given bass level. Model the Peerless CSX 10" in an 80L box, tune to 25 Hz or so-take a look at that curve. Blows the 8 inchers away.
C) If you want to use the P21 in a sealed box, forget it. It only has ±¼ inch, (6mm) linear travel. That gives it a total amount of moved air, (volume displacement) of around 8 in³. If you look at the following chart, you see that 8 in³ only amounts to about 102 dB at 50 Hz. Forget about 40 Hz or low 30's with this driver. Remember that your hearing falls off at the bass frequencies, so going up well above 100 dB is a necessity down there.
http://www.diyaudio.com/forums/showthread.php?threadid=5668&highlight=displacement+SPL Hit F11-makes chart easier to read. Chart applies only to sealed systems-ported have higher output at those volume levels.
If you need to go vented, which you do to obtain usable output at the frequencies you mention, then go to the 10 incher which occupies no greater box volume than what you are prepared to build for the 8 incher, but gives better bass extension, significantly higher output, and compared to the Vifa, much, much cleaner sound.
PS: The other method speakers use, besides the Faraday ring, to prevent "suck-out" at low frequencies is the "extended pole piece" or "extended core"-the same thing. The Vifa makes no mention of either "extended pole piece" or "Faraday, (short circuit) ring", so we have to assume that it does not have it. It's a plus, so if it had it, Vifa would let you know.
Wiz, thanks for your reply. I feel like I've been slapped around.
I modelled a 10" CSX and a P21 both in an 80L box as per your suggestion, in WinISD.
WinISD shows a slightly later rolloff with the 10" but the SPLs are the same. 2 x P21s in an 80L give me a 91db SPL and 1 x 10" CSX gives me 88db.
2 x 8" HDS in at 80L tuned to 40hz gives me nearly 94db SPL but a drop in gain of about 1.5db from 100hz to it's rolloff at 45hz. F3 here is 40hz. The SPL chart mirrors that.
The specs are confirmed. The boxes are sealed. Can you see why I'm confused. Be gentle.
Mos
I modelled a 10" CSX and a P21 both in an 80L box as per your suggestion, in WinISD.
WinISD shows a slightly later rolloff with the 10" but the SPLs are the same. 2 x P21s in an 80L give me a 91db SPL and 1 x 10" CSX gives me 88db.
2 x 8" HDS in at 80L tuned to 40hz gives me nearly 94db SPL but a drop in gain of about 1.5db from 100hz to it's rolloff at 45hz. F3 here is 40hz. The SPL chart mirrors that.
The specs are confirmed. The boxes are sealed. Can you see why I'm confused. Be gentle.
Mos
Mos Fetish said:
I'm getting a little confused too! Is this speaker to be vented or sealed? What is your max box volume and your desired F3. I have a spreadsheet I made for a client where you can look up F3 and box volume and determine maximum sensitivity...at these frequencies the box dimensions determine all.
Also, on several occasions you've mentioned that the graphs in WinISD get a little crazy, can you capture one of those graphs, post it and tell us what you don't like about it?
Scott
Mos, whats your target SPL?
This will help determine if you need 2 drivers/paralleled or only 1.
Keep in mind WinISD does not include electical SPL gain/loss (parallel/series) with multiple drivers - it only adds 3db per driver (acoustical gain).
This will help determine if you need 2 drivers/paralleled or only 1.
Keep in mind WinISD does not include electical SPL gain/loss (parallel/series) with multiple drivers - it only adds 3db per driver (acoustical gain).
Hi Scott, AP
Ok. Here's the gain graph from WinISD for the 850490 8" HDS.
And, sorry, typo above. I should have said: these boxes aren't sealed. They're vented.
The blue line is the default response from WinISD.
The red and green are tuned at 40hz and with FBs of 85 and 65 litres. The 65L has an F3 of 44hz and the 85 is at 40.
0 db on the gain chart is equivalent to 93.5db on the SPL chart. With +3db more for parallel connection, that suits me fine. Midrange suggestions, anyone? 🙂
Group delay at 40hz for the 65 and 85L boxes shows quite a spike to 13-16ms.
Now, I'll obviously have to take this under advisement, but, and I'm only comparing this to the P21 response, that dip from 100hz down to the rolloff, of at least 1db-1.5db doesn't look ideal. Or, am I being too concerned about this?
I appreciate what Wiz said about the Faraday ring on the Peerless units but surely that's only a factor at very high excursions? Or am I wrong?
Plus, I found it strange that such a good driver with a low FS like the 850490 was showing that suggested configuration in WinISD. I assume that's WinISD and not the driver at fault there because a suggested F3 of 60hz certainly doesn't look impressive for an 8" driver.
Be gentle with me, guys. I thought I had this settled using P21s--then I saw the Peerless units and thought they were worth a try.
Mos
Ok. Here's the gain graph from WinISD for the 850490 8" HDS.
And, sorry, typo above. I should have said: these boxes aren't sealed. They're vented.
The blue line is the default response from WinISD.
The red and green are tuned at 40hz and with FBs of 85 and 65 litres. The 65L has an F3 of 44hz and the 85 is at 40.
0 db on the gain chart is equivalent to 93.5db on the SPL chart. With +3db more for parallel connection, that suits me fine. Midrange suggestions, anyone? 🙂
Group delay at 40hz for the 65 and 85L boxes shows quite a spike to 13-16ms.
Now, I'll obviously have to take this under advisement, but, and I'm only comparing this to the P21 response, that dip from 100hz down to the rolloff, of at least 1db-1.5db doesn't look ideal. Or, am I being too concerned about this?
I appreciate what Wiz said about the Faraday ring on the Peerless units but surely that's only a factor at very high excursions? Or am I wrong?
Plus, I found it strange that such a good driver with a low FS like the 850490 was showing that suggested configuration in WinISD. I assume that's WinISD and not the driver at fault there because a suggested F3 of 60hz certainly doesn't look impressive for an 8" driver.
Be gentle with me, guys. I thought I had this settled using P21s--then I saw the Peerless units and thought they were worth a try.
Mos
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