My data -
I have an enclosure with 8" X 8.5" X 30" internal volume (1.167 cu. ft. ). It had (semi) working bass
drivers (warped voice coils). I heard the sound of the originals but proceeded to
"finish" off the woofers with my big amp. No idea of the original specs for these
drivers.
I bought some cheap drivers for replacement - MCM Audio Select 8" Woofer with Poly Cone and Rubber Surround 70W RMS at 8ohm | 55-2971 (552971) | MCM Audio Select
The sound was "OK" , but not as deep and refined as the originals.
(Qts of .45)
Now , I'm looking at the Dayton 215-8 or the 225-8 as a better replacement.
Both of these have a Qts of .34-.36 ...
The 225 has the larger Vas of the 2 - 2.18
I used the online box calc here : Speaker Box Enclosure Designer / Calculator
It shows a volume of .78 cu. ft. for the 215-8 and a perfect 1.16 for the 225-8.. both with a 2" port at 4+ " (tuned the enclosures for 45hz).
The 215-8 is the perfect fit , physically - so , I really would prefer it. My
question is , could I use my larger volume enclosure for the 215-8 even as it
"prefers" a .7-.8 cu. ft. one ???
I'm about to buy them , so any advice is welcome.
OS
I have an enclosure with 8" X 8.5" X 30" internal volume (1.167 cu. ft. ). It had (semi) working bass
drivers (warped voice coils). I heard the sound of the originals but proceeded to
"finish" off the woofers with my big amp. No idea of the original specs for these
drivers.
I bought some cheap drivers for replacement - MCM Audio Select 8" Woofer with Poly Cone and Rubber Surround 70W RMS at 8ohm | 55-2971 (552971) | MCM Audio Select
The sound was "OK" , but not as deep and refined as the originals.
(Qts of .45)
Now , I'm looking at the Dayton 215-8 or the 225-8 as a better replacement.
Both of these have a Qts of .34-.36 ...
The 225 has the larger Vas of the 2 - 2.18
I used the online box calc here : Speaker Box Enclosure Designer / Calculator
It shows a volume of .78 cu. ft. for the 215-8 and a perfect 1.16 for the 225-8.. both with a 2" port at 4+ " (tuned the enclosures for 45hz).
The 215-8 is the perfect fit , physically - so , I really would prefer it. My
question is , could I use my larger volume enclosure for the 215-8 even as it
"prefers" a .7-.8 cu. ft. one ???
I'm about to buy them , so any advice is welcome.
OS
Hi OS,
The dayton 215 should fit well in the 1.17 cubic foot box tuned to 41Hz. The alignment becomes an extended bass shelf (EBS). Have a look at the 2 graphs, the one in red is the larger enclosure. Much better bass extension. Can handle a full 100W to 30Hz before X-max becomes an issue. (104dB at 30Hz).
The dayton 215 should fit well in the 1.17 cubic foot box tuned to 41Hz. The alignment becomes an extended bass shelf (EBS). Have a look at the 2 graphs, the one in red is the larger enclosure. Much better bass extension. Can handle a full 100W to 30Hz before X-max becomes an issue. (104dB at 30Hz).
Attachments
On my above link , I did go lower with the 215 (40Hz) , it suggested a 5" port
(2" dia).
I did not subtract the generous internal bracing or the woofer/port Volume/foam padding from
the enclosure volume. It might be closer to 1 cu. ft. (28L).
So... the larger enclosure allows for lower tunings. COOL , 104db at 30HZ !
Have you used either of these dayton's ?
OS
Hi,
The 215-8 will be fine in the bass end. However its top
end has a large peak that may need controlling in the x/o.
the 225-8 has an even more problematic dip and peak.
a 2 way may have problems, a 3 way should be OK.
rgds, sreten.
You don't subtract foam lining for volume calculations.
The 215-8 will be fine in the bass end. However its top
end has a large peak that may need controlling in the x/o.
the 225-8 has an even more problematic dip and peak.
a 2 way may have problems, a 3 way should be OK.
rgds, sreten.
You don't subtract foam lining for volume calculations.
Last edited:
I saw that peak , and when I googled to find some builders of 215-8 systems .. they said to cross it over "low" .
I'm using the existing XO from the original enclosures , I think they are 1.5K
second order.
BTW , these are the mission 763i 's . No SPECS!
In the near future , I do want to upgrade the cheap caps and inductors.
It now has a air core HPF and a ferrite core LPF + NP electrolytic's - cheap
(economical ? )
.OS
Hi,
You most likely will have problems using the original x/o.
The 10dB rise from 1KHz to 3KHz will be an issue.
(Unless by luck the original driver was similar.)
rgds, sreten.
These would probably work better :
Peerless SKO204 8 inch hifi bass woofers speakers | eBay
You most likely will have problems using the original x/o.
The 10dB rise from 1KHz to 3KHz will be an issue.
(Unless by luck the original driver was similar.)
rgds, sreten.
These would probably work better :
Peerless SKO204 8 inch hifi bass woofers speakers | eBay
The 215-8 is the perfect fit , physically - so , I really would prefer it. My
question is , could I use my larger volume enclosure for the 215-8 even as it
"prefers" a .7-.8 cu. ft. one ???
Hi OS
The DS215-8 can be used with your current box. Simply tune it lower (see attachment).
I have the SD215A-88 DVC model which is cheaper. Voice coil must be paralleled for 4 ohms. The SD215A-88 can also be loaded in your box. I'm using it strictly for sub, crossing anywhere from 70Hz-100Hz (24dB/oct).
If you need to cross higher, I suggest the Peerless 830869. This driver can cross at 1.5kHz.
Regards
Mike
Attachments
I really want to use the 215-8 (it's a perfect fit) , I have minimal woodworking tools.
Could the XO be "tweaked" to mitigate any peaks in the dayton ?
I estimated that XO (1.5K) from the scant info I could dredge up from the internet and the specs on the original tweeters (they were also blown).
I'm now using these ... MCM Audio Select 1" Soft Dome Tweeter with 103mm Round Frame | 53-1370 (531370) | MCM Audio Select
So far - good , I've hammered these with the full "wrath" of my 125W amp , crystal clear and I cannot blow them
.(BELOW) is the XO in schematic form.
I could test R1 and R2 - both are 1R @ 7W.
L1 (the woofer inductor) is a ferrite slug 12.5mm thick by 25mm long wrapped by 120 windings of 18ga enameled wire. It's outer diameter (the whole inductor) is about 22mm.
L2 (tweeter inductor).. is a plastic bobbin (air core) @ 15mm ID X 30mm OD X 12.5mm wide , it has 90+ windings of the same 18ga wire.
C1 and C2 are buried in glue
... I would most likely destroy them to determine the values.I could of bought replacements for all the mission drivers , but they looked
kind of cheap (small magnets , no pole vents , 20mm VC's).
I need something (bass driver wise) that can take a bit of abuse. The lowly MCM tweeters definitely can.
OS
Attachments
Last edited:
Hi,
Your current arrangement with cheap tweeters and and cheap bass
units is probably are far as you can go with the original crossovers.
As soon as you start looking at expensive drivers your on a hiding
to nothing trying to get them to work as effectively as they cost.
Fold pieces of ~ 1cm thick foam 3 x port diameter x port depth *
into the ports for the MCM drivers, will give you tighter deeper bass.
They look like the bottom may be closed off for sand filling.
rgds, sreten.
* Foam cleaning sponges work well, 3 for £1.
Your current arrangement with cheap tweeters and and cheap bass
units is probably are far as you can go with the original crossovers.
As soon as you start looking at expensive drivers your on a hiding
to nothing trying to get them to work as effectively as they cost.
An externally hosted image should be here but it was not working when we last tested it.
Fold pieces of ~ 1cm thick foam 3 x port diameter x port depth *
into the ports for the MCM drivers, will give you tighter deeper bass.
They look like the bottom may be closed off for sand filling.
rgds, sreten.
* Foam cleaning sponges work well, 3 for £1.
Last edited:
I need a little more.
I can only find my speakers , wish I could build them.
I understand the current XO (below 1) is cheap , maybe a little better than the super
cheap 1st order ones in the low end units , but ... still cheap.
I will try your suggestion to tighten the MCM's bass response.
I have the 10" "big brother" (below 2) to the 8" MCM.....converting to a sealed enclosure (40L) gave it much more defined bass.
These MCM's seem to be designed for sealed applications.
I am willing to totally redesign the XO (I have lots of industrial enameled wire) and can purchase caps/resistors.
BTW , here are the current mission's (last pix).
The bass does have the extension down to 45Hz , same as the originals , but the midbass is exaggerated (higher level). Also , the mcm's run out of Xmax unless I "back off" at 40-60Hz on my EQ.
The 10" units below exhibited the same characteristics until I sealed the enclosures.
OS
I can only find my speakers , wish I could build them.
I understand the current XO (below 1) is cheap , maybe a little better than the super
cheap 1st order ones in the low end units , but ... still cheap.
I will try your suggestion to tighten the MCM's bass response.
I have the 10" "big brother" (below 2) to the 8" MCM.....converting to a sealed enclosure (40L) gave it much more defined bass.
These MCM's seem to be designed for sealed applications.
I am willing to totally redesign the XO (I have lots of industrial enameled wire) and can purchase caps/resistors.
BTW , here are the current mission's (last pix).
The bass does have the extension down to 45Hz , same as the originals , but the midbass is exaggerated (higher level). Also , the mcm's run out of Xmax unless I "back off" at 40-60Hz on my EQ.
The 10" units below exhibited the same characteristics until I sealed the enclosures.
OS
Attachments
Last edited:
Hi,
A properly designed crossover is far better than half arsed
stupid generic crossover even though it cost the same.
For your cheap drivers you current x/o is far better than
any of the generic stuff you could buy, trust me on this.
(A lot better but not necessarily right, but a lot nearer.)
PE has the frd files and zma files for a properly designed x/o.
But you don't have them for the tweeter which is a problem.
Still I think you should detune the port, play around
with the treble resistor a little and then call it quits.
i.e. Quit whilst your ahead before spending more and
getting yourself into some irresolvable problems.
The port detuning in this case will work very well.
Cleaning sponges cut to size will work very well.
Here you might as well let the foam extend about
1cm beyond the back of the port and flush with
the start of the curve at the front, to look nice.
rgds, sreten.
The other option IMO is repurpose the cabinets with
a new front baffle for a good design for the cabinets.
A properly designed crossover is far better than half arsed
stupid generic crossover even though it cost the same.
For your cheap drivers you current x/o is far better than
any of the generic stuff you could buy, trust me on this.
(A lot better but not necessarily right, but a lot nearer.)
PE has the frd files and zma files for a properly designed x/o.
But you don't have them for the tweeter which is a problem.
Still I think you should detune the port, play around
with the treble resistor a little and then call it quits.
i.e. Quit whilst your ahead before spending more and
getting yourself into some irresolvable problems.
The port detuning in this case will work very well.
Cleaning sponges cut to size will work very well.
Here you might as well let the foam extend about
1cm beyond the back of the port and flush with
the start of the curve at the front, to look nice.
rgds, sreten.
The other option IMO is repurpose the cabinets with
a new front baffle for a good design for the cabinets.
Last edited:
For passive crossover designer 7 ?
Sounds like a good way to learn...
I can always buy new tweeters. The 85mm holes I had to make for the present
tweeters seem to accommodate most of the Vifa and dayton soft domes .
OS
Hi,
Dunno, I like the free FRD tools and dislike some tools that are wrong.
FRD Consortium tools guide
Designing Crossovers with Software Only
Its probably not escaped your notice 8"/ 1" 2 ways are near
non existent nowadays and an 8" driver good in the mid
as opposed to being developed for bass is very rare.
Up to you, but I advise quitting whilst your ahead.
Learning by analysing other good designs is IMO
by far the best way of learning the stuff, YMMV.
rgds, sreten.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.