If anyone's interested in this driver combination, here's information from a person who built these speakers using my crossover design.
-jAy
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Hi Jay,
I`ve just finished your Seas ER18RNX TM design with 27TBFC/G tweeter option. I`ve used my own sandwich (MDF + plywood) enclosure design with front mounted Precisoion Port and Sonic Barrier dampening. Crossover and driver spacing is exactly the same as on your drawings and I have to admit that I`m impressed with sound quality of this speakers. Thank you for creating and posting this great design on your website.
At the moment I`m testing these speakers and I use Plilips DVD as a source cause I`m waitng for a new DAC. Anyway I can write some first impressions.
I`m using a 16,5 litres enclosure with bass reflex tuned at 35 Hz. In my small listening room (15 m2) bass response is very smooth with very nice low end extension. Low tuning provieds a bit lean bass with soft roll off which combined with room gain allows even 30-35 Hz tones to be well defined.
Tonal balance is very even, in my opinion full BSC is an exellent choice for those speakers. Overall response is very smooth and sound stage is huge in every dimension. Speakers just "disappear" in my listening room and completely fill it with sound. 27TBFC/G is really a great tweeter and I didn`t noticed any kind of stress from it crossed over at 1550 Hz, even at very high SPL.
For now I just can`t write any negatives. For a 2 way monitor with single 18 cm woofer they are just amaizing in every aspect. I belive that such great results are achived through well designed crossover combined with good drivers and extreamly rigid sandwich enclosure with additional wood bracing and two separated chambers for tweeter/crossover network.
Most factory speakers sound thin and boomy compared to them because of manufacturer's limitations. They can`t cross too low cause they are afraid of tweeters being overloaded, they use thin and simple enclosures cause they are much cheaper, they use only few db BSC cause speakers must sound lound in shop and have high "on paper" sensitivity. All those limitations provides poor performance when compared to well designed DIY
speakers and it`s very easy to hear the difference. At the moment they are absolutely the best monitors I`ve ever heard.
I`m using them with an old Sony TAF670ES solid state amp (90/140W) and low sensitivity is not a problem for me. Anyway even though those speakers have around 83 db sensitivity I find them at least as sensitive as some speakers I had with 87-88 db sensitivity claimed by their manufacturer.
Btw, there is still some work to be done to make those speakers look really good, but meantime feel free to use those fotos.
- Chris
-jAy
--------------------------------------------
An externally hosted image should be here but it was not working when we last tested it.
Hi Jay,
I`ve just finished your Seas ER18RNX TM design with 27TBFC/G tweeter option. I`ve used my own sandwich (MDF + plywood) enclosure design with front mounted Precisoion Port and Sonic Barrier dampening. Crossover and driver spacing is exactly the same as on your drawings and I have to admit that I`m impressed with sound quality of this speakers. Thank you for creating and posting this great design on your website.
At the moment I`m testing these speakers and I use Plilips DVD as a source cause I`m waitng for a new DAC. Anyway I can write some first impressions.
I`m using a 16,5 litres enclosure with bass reflex tuned at 35 Hz. In my small listening room (15 m2) bass response is very smooth with very nice low end extension. Low tuning provieds a bit lean bass with soft roll off which combined with room gain allows even 30-35 Hz tones to be well defined.
Tonal balance is very even, in my opinion full BSC is an exellent choice for those speakers. Overall response is very smooth and sound stage is huge in every dimension. Speakers just "disappear" in my listening room and completely fill it with sound. 27TBFC/G is really a great tweeter and I didn`t noticed any kind of stress from it crossed over at 1550 Hz, even at very high SPL.
For now I just can`t write any negatives. For a 2 way monitor with single 18 cm woofer they are just amaizing in every aspect. I belive that such great results are achived through well designed crossover combined with good drivers and extreamly rigid sandwich enclosure with additional wood bracing and two separated chambers for tweeter/crossover network.
Most factory speakers sound thin and boomy compared to them because of manufacturer's limitations. They can`t cross too low cause they are afraid of tweeters being overloaded, they use thin and simple enclosures cause they are much cheaper, they use only few db BSC cause speakers must sound lound in shop and have high "on paper" sensitivity. All those limitations provides poor performance when compared to well designed DIY
speakers and it`s very easy to hear the difference. At the moment they are absolutely the best monitors I`ve ever heard.
I`m using them with an old Sony TAF670ES solid state amp (90/140W) and low sensitivity is not a problem for me. Anyway even though those speakers have around 83 db sensitivity I find them at least as sensitive as some speakers I had with 87-88 db sensitivity claimed by their manufacturer.
Btw, there is still some work to be done to make those speakers look really good, but meantime feel free to use those fotos.
- Chris
An externally hosted image should be here but it was not working when we last tested it.
Here are some more photos showing crossover and cabinet building. Impeccable work all around. I'm very impressed.
-jAy
-jAy
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An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Port Location
Jay & Chris-
Very nice, both of you. Jay, I have browsed your speaker building website, am interested in your designs because you are a classical music afficianado, as am I. I think it's more difficult to find speakers that do well with classical, particularly the violin. Most speakers do OK at lower volumes but, get an orchestra going full tilt & violins harden up & get harsh pretty quick !
Also, Jay/Chris, most bass reflex speakers have the port in back, yours are in front. What are the pros & cons of each ?? Is it only cosmetic or are their acoustical reasons as well. Seems to me , with the port in front, the speaker wouldn't need to be as far out from the wall to avoid muddying the midrange.
The enclosures look larger than the ones Krutke (SR71) uses for the same drivers. If so, is this part of the deeper but leaner bass ?? The dowels , I assume, is to align the box pieces during assembly ? Good idea !
Like many people on this forum, a relative newbie here, just trying to get informed & educated. Thanks.
Dave
Jay & Chris-
Very nice, both of you. Jay, I have browsed your speaker building website, am interested in your designs because you are a classical music afficianado, as am I. I think it's more difficult to find speakers that do well with classical, particularly the violin. Most speakers do OK at lower volumes but, get an orchestra going full tilt & violins harden up & get harsh pretty quick !
Also, Jay/Chris, most bass reflex speakers have the port in back, yours are in front. What are the pros & cons of each ?? Is it only cosmetic or are their acoustical reasons as well. Seems to me , with the port in front, the speaker wouldn't need to be as far out from the wall to avoid muddying the midrange.
The enclosures look larger than the ones Krutke (SR71) uses for the same drivers. If so, is this part of the deeper but leaner bass ?? The dowels , I assume, is to align the box pieces during assembly ? Good idea !
Like many people on this forum, a relative newbie here, just trying to get informed & educated. Thanks.
Dave
Re: Port Location
I find that one of the reasons why music doesn't sound right is recording quality. In theory, Redbook CD should be nearly "lossless" when recorded properly. But in many cases, music's mastered poorly on CDs. Have you tried SACD and DVD-A? Most of them are much better than CD.
In fact, front-porting is not what makes the speakers usable close to walls. A major factor in close placement to walls is baffle step loss / boundary reinforcement issue, not the port location. In theory, only a few inch clearance between the port opening and the wall is enough for the proper functioning of the port. BTW, here's a good experiment about the effect of port location in BR system:
http://www.zaphaudio.com/tidbits/
Find "Front port mounting" in the middle of the page.
A little taller baffle can change the midrange tonal balance a bit, but it won't do so dramatically. A major difference between Zaph's design and mine is more in a little different baffle step compensation and crossover point as I pointed out in my web page.
DavidLR said:
I find that one of the reasons why music doesn't sound right is recording quality. In theory, Redbook CD should be nearly "lossless" when recorded properly. But in many cases, music's mastered poorly on CDs. Have you tried SACD and DVD-A? Most of them are much better than CD.
In fact, front-porting is not what makes the speakers usable close to walls. A major factor in close placement to walls is baffle step loss / boundary reinforcement issue, not the port location. In theory, only a few inch clearance between the port opening and the wall is enough for the proper functioning of the port. BTW, here's a good experiment about the effect of port location in BR system:
http://www.zaphaudio.com/tidbits/
Find "Front port mounting" in the middle of the page.
A little taller baffle can change the midrange tonal balance a bit, but it won't do so dramatically. A major difference between Zaph's design and mine is more in a little different baffle step compensation and crossover point as I pointed out in my web page.
Jay, on your site you show your phase tracking between the tweeter and woofer:
Do you have such a graph for Zaph's design?
An externally hosted image should be here but it was not working when we last tested it.
Do you have such a graph for Zaph's design?
Re: Port Location
I noticed he used a sealed compartment for the x-over which sacrifices some of the volume. By how much larger is it larger?Who knows. But Zaph did hint in another forum that if he was building the enclosures from scratch he would have gone to 16L instead of the Madisound's 14L.
Peter
DavidLR said:
I noticed he used a sealed compartment for the x-over which sacrifices some of the volume. By how much larger is it larger?Who knows. But Zaph did hint in another forum that if he was building the enclosures from scratch he would have gone to 16L instead of the Madisound's 14L.
Peter
Re: Re: Port Location
Oh, I only considered the baffle size, not the cab volume, when I replied to Dave. Notice that he also used a separate sealed chamber for the tweeter, too. He must be perfectionistic. So he used 16.5 liter net volume for BR tuning and tuned the port to 35 Hz, which I think will work a bit more optimally than the SR71 kit's volume and tuning.
peter_m said:
Oh, I only considered the baffle size, not the cab volume, when I replied to Dave. Notice that he also used a separate sealed chamber for the tweeter, too. He must be perfectionistic. So he used 16.5 liter net volume for BR tuning and tuned the port to 35 Hz, which I think will work a bit more optimally than the SR71 kit's volume and tuning.
Cab Volume
Yes- cab volume is what I was referring to. I had a chance to audition the SR71's & was pleased by both the sound & small size of the box. The picture of Chris' box appeared to be larger but perhaps it wasn't. Hard to tell sometimes from pics.
Re the port, I understand some of what you say. I"ll take your educated word for it. I've always understood that a speaker close to the wall usually reinforces the bass at the expense of clarity, unless the speaker was specifically designed to take that into account.
Yes- cab volume is what I was referring to. I had a chance to audition the SR71's & was pleased by both the sound & small size of the box. The picture of Chris' box appeared to be larger but perhaps it wasn't. Hard to tell sometimes from pics.
Re the port, I understand some of what you say. I"ll take your educated word for it. I've always understood that a speaker close to the wall usually reinforces the bass at the expense of clarity, unless the speaker was specifically designed to take that into account.
Re: Cab Volume
His cabinet should be much larger than the SR71's. The 16.5 liter net volume doesn't include the sealed compartments for crossover and tweeter.
You're right about bass reinforcement caused by placing a speaker close to walls. What I meant in the above is that a design like this, which has full baffle step compensation, shouldn't be used close to walls *regardless* of port location. Also, it is more reasonable that a design with a small amount of BSC for being used close to walls has front porting. I simply meant that port location is not a major design element of a near-wall speaker. Sorry for the confusion.
DavidLR said:
His cabinet should be much larger than the SR71's. The 16.5 liter net volume doesn't include the sealed compartments for crossover and tweeter.
You're right about bass reinforcement caused by placing a speaker close to walls. What I meant in the above is that a design like this, which has full baffle step compensation, shouldn't be used close to walls *regardless* of port location. Also, it is more reasonable that a design with a small amount of BSC for being used close to walls has front porting. I simply meant that port location is not a major design element of a near-wall speaker. Sorry for the confusion.
Chris (the builder of this design) is not a member here yet. But he read this thread and emailed me his answers to some of the questions discussed here. A good point about the effect of front porting on the near-field bass level.
------------------------
Thanks for the link and posting all those info. Its really nice to read other people comments on international forum about my little home work
Later I`ll register to participate in discusion, meantime I`m sending you some more comments on enclosures construction, ofcourse you are free to use them.
Front port mounting is critical for nearfield listening bass level. Ports mounted on back have around 3db less nearfield output caused by much bigger distance difference between port, speaker and listener. In normal listening position this difference disapear, 30 cm is not so important when you are 2-3 meters away from speakers. Sometimes I listen to those speakers in nearfield positioning and I wanted them to be universal.
My enclosures are 56x23x32 cm and they weigh 20 kilograms each Such size and weight is caused not only by separated chambers for tweeter and crossover network but also by thick enclosure walls. Most of them are 28mm (12mm chipboard + 12mm plywood + 4mm poliurethan bittumen pads), front is 30mm and bottom is 34 mm thick
Angled partitions allows more port clarence and reduce standing waves. Whole chipboard frame is few times impregnated with watered down glue. All wood dowels were applied after glueing the frame. I used them to gain more contact surface beetwen glued elements, also wood dowels combined with wood bracing work as a third material in sandwich construction. Each one of them has a bit different properties so all 3 combined together are less prone to single frequency mod (some of those dowels are even 70mm long).
For me its first time to build such complex eclosures and I`m still amazed how rigid and well damped they are.
Chris
------------------------
Thanks for the link and posting all those info. Its really nice to read other people comments on international forum about my little home work
Later I`ll register to participate in discusion, meantime I`m sending you some more comments on enclosures construction, ofcourse you are free to use them.Front port mounting is critical for nearfield listening bass level. Ports mounted on back have around 3db less nearfield output caused by much bigger distance difference between port, speaker and listener. In normal listening position this difference disapear, 30 cm is not so important when you are 2-3 meters away from speakers. Sometimes I listen to those speakers in nearfield positioning and I wanted them to be universal.
My enclosures are 56x23x32 cm and they weigh 20 kilograms each
Such size and weight is caused not only by separated chambers for tweeter and crossover network but also by thick enclosure walls. Most of them are 28mm (12mm chipboard + 12mm plywood + 4mm poliurethan bittumen pads), front is 30mm and bottom is 34 mm thick Angled partitions allows more port clarence and reduce standing waves. Whole chipboard frame is few times impregnated with watered down glue. All wood dowels were applied after glueing the frame. I used them to gain more contact surface beetwen glued elements, also wood dowels combined with wood bracing work as a third material in sandwich construction. Each one of them has a bit different properties so all 3 combined together are less prone to single frequency mod (some of those dowels are even 70mm long).
For me its first time to build such complex eclosures and I`m still amazed how rigid and well damped they are.
Chris
Baffle Step
Trying to understand baffle step issues here, this is my rudimentary understanding after some internet reading. Please let me know if I've got something of a grasp here.
Baffle step diffraction compensation & related issues-
a) Sound waves tend to flow in all directions, including around & behind the speaker. The higher frequencies with wavelengths shorter than the baffle will still try to flow everywhere , but because they are shorter than the baffle, they will just reflect forward to the listener, thereby accentuating the higher frequencies. As much as 6db accentuation if I read right. Correcting for this 6db is a "full" baffle step comp. ?
b) The resulting tonal imbalance is compensated for in the crossover circuitry by attenuation of the relevant high frequencies, giving a flatter frequency response.
c) Moving the speaker closer to the rear wall muddies up the flatter frequency response achieved by the BSC circuit. This was your point Jay ? A full baffle step compensation has already been applied, no need to muck it up by putting the speakers to close to the wall.
d) Although it still seems counter-intuitive to me, rear port placement
is a non-factor when considering bass response. The real issue is bass emphasis caused by the lower frequencies flowing around the cabinet, being reinforced by the rear wall.
e) After reading about various designs & room placement of speakers, it seems that sealed cab. designs are more tolerant of close wall placement. Is this true ?? Seems like it shouldn't make a difference, at least in regards to BSC, two identical boxes, one ported, one not, still have the same BSC issues I would think. Anyway, thanks for any response & ensuing education on my behalf !!
Dave
Trying to understand baffle step issues here, this is my rudimentary understanding after some internet reading. Please let me know if I've got something of a grasp here.
Baffle step diffraction compensation & related issues-
a) Sound waves tend to flow in all directions, including around & behind the speaker. The higher frequencies with wavelengths shorter than the baffle will still try to flow everywhere , but because they are shorter than the baffle, they will just reflect forward to the listener, thereby accentuating the higher frequencies. As much as 6db accentuation if I read right. Correcting for this 6db is a "full" baffle step comp. ?
b) The resulting tonal imbalance is compensated for in the crossover circuitry by attenuation of the relevant high frequencies, giving a flatter frequency response.
c) Moving the speaker closer to the rear wall muddies up the flatter frequency response achieved by the BSC circuit. This was your point Jay ? A full baffle step compensation has already been applied, no need to muck it up by putting the speakers to close to the wall.
d) Although it still seems counter-intuitive to me, rear port placement
is a non-factor when considering bass response. The real issue is bass emphasis caused by the lower frequencies flowing around the cabinet, being reinforced by the rear wall.
e) After reading about various designs & room placement of speakers, it seems that sealed cab. designs are more tolerant of close wall placement. Is this true ?? Seems like it shouldn't make a difference, at least in regards to BSC, two identical boxes, one ported, one not, still have the same BSC issues I would think. Anyway, thanks for any response & ensuing education on my behalf !!
Dave
Re: Baffle Step
Hi,
a) is not wrong.
b) is corrrect.
c) Near wall placement raises lower bass. It unbalances full BSC
and the near wall palcement by default sounds some what muddled.
But if near boundary use is expected, full BSC should not be used.
d) Farfield this is true.
e) I'd say its not true in terms of accuracy. In terms of bass below
100Hz it may be true for the same driver in a sealed box half the
size of a vented box compared to the vented case, simply due
to less bass output to cause standing mode problems.
Freefield placement for good imaging and full BSC also allows the
untilisation of the boundaries to extend deep bass (rather than
beef up upper bass). Sealed box (Q ~ .6/.65) and overdamped
lowered port tuning vented alignments can utilise room gain
in the bass region to achieve very impressive extension.
You cannot do this with speakers designed for near walls as much.
/sreten.
DavidLR said:
Hi,
a) is not wrong.
b) is corrrect.
c) Near wall placement raises lower bass. It unbalances full BSC
and the near wall palcement by default sounds some what muddled.
But if near boundary use is expected, full BSC should not be used.
d) Farfield this is true.
e) I'd say its not true in terms of accuracy. In terms of bass below
100Hz it may be true for the same driver in a sealed box half the
size of a vented box compared to the vented case, simply due
to less bass output to cause standing mode problems.
Freefield placement for good imaging and full BSC also allows the
untilisation of the boundaries to extend deep bass (rather than
beef up upper bass). Sealed box (Q ~ .6/.65) and overdamped
lowered port tuning vented alignments can utilise room gain
in the bass region to achieve very impressive extension.
You cannot do this with speakers designed for near walls as much.
/sreten.Baffle Step
Sreten-
Thanks for your response. I like your finely shaded answers, especially answers to A & B. B is "correct" but A is merely "not wrong" Funny!
I do understand this is the briefest of summaries on BSC. I'm just trying to summarize & learn using laymen's terms.
Not wrong works for me !
Under D, yes, I understand. Better nearfield bass response is what Chris is achieving here by putting the port in front.
Dave
Sreten-
Thanks for your response. I like your finely shaded answers, especially answers to A & B. B is "correct" but A is merely "not wrong" Funny!
I do understand this is the briefest of summaries on BSC. I'm just trying to summarize & learn using laymen's terms.
Not wrong works for me !
Under D, yes, I understand. Better nearfield bass response is what Chris is achieving here by putting the port in front.
Dave
I`m finaly here to answer some questions about my cabinet design and share some general speaker building informations. I hope that I`ll be able to help
I appreciate your positive feedback on my speakers. At this point I would like to thank Jay and people from polish forum - misomor and eMil. They really helped me a lot in understanding basic loudspeaker design principles.
Btw. my account was already here but I just forgot about it
I appreciate your positive feedback on my speakers. At this point I would like to thank Jay and people from polish forum - misomor and eMil. They really helped me a lot in understanding basic loudspeaker design principles.
Btw. my account was already here but I just forgot about it
Zaph|Audio SR71
Old zombie thread - but thought I'd ask as I'm looking at the ZA-SR71 build at the moment and wondered what the reason was behind using the metal dome as opposed to the soft dome found in the Madison kit?
I'd also be interested to know what the decision to tune it lower was inspired by and what size room you use it in ?
I`m finaly here to answer some questions about my cabinet design and share some general speaker building informations. I hope that I`ll be able to help
I appreciate your positive feedback on my speakers. At this point I would like to thank Jay and people from polish forum - misomor and eMil. They really helped me a lot in understanding basic loudspeaker design principles.
Btw. my account was already here but I just forgot about it
Old zombie thread - but thought I'd ask as I'm looking at the ZA-SR71 build at the moment and wondered what the reason was behind using the metal dome as opposed to the soft dome found in the Madison kit?
I'd also be interested to know what the decision to tune it lower was inspired by and what size room you use it in ?
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