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Due to space considerations I am looking for a front ported 2-way. Could use some sugestions. Thanks in advance.
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For 1K you could get a pair of Adam A7's. Adam A7's are active monitors.
I have the KEF XQ1 which I've purchased recently. They're pretty amazing speakers for the size and price. While they retail for $1500 a pair, I found them on Amazon for 1/2 that. I still haven't put enough time into them, but they definitely are sounding better and better. They are front ported 3 way bookshelf speakers, though I believe some of the newer KEFs are front ported 2-ways.
I wish somebody would compare the RMA Europa, DCM TF 200,Audio Note AX 2 and Monitor Audio RS6 for the benefit of all those struggling to pick a $1000 speaker.
The most important audio purchase I've made thus far.
__________________
Forget about front or rear-ported, and don't forget to read the Bound for Sound and Affordable Audio reviews.
Used pair of Sonus Faber Concerto. Their are a couple pairs on audiogon right now.
Used JMR Twin MK III's or Sigs if you can find them.
The Reynaud Twins are simply the best speakers I've ever owned, and a great value. You should be able to get a used pair for well under a grand, or a new pair for about a grand. Warm, musical, involving, non-fatiguing. magic.
Actually the new Twin Sigs are $1295 and stock is running low. Replacement Duets will probably run a couple of hundred more, no firm estimate yet from France.
Highly regarded, front ported, with surprising bass from such a small cabinet. They do require nearly 150 hours to break in so don't let a new pair scare you to death. Their sound and fit and finish make them true bargains.520's will easily fit on a bookshelf and make a believer out of you: big sound can come from a small driver. Some internet wag said "85% of the sound of a Proac at 1/5 the price". (They are about the same size and Usher also uses a clear cone.)
If you live near a dealer make the trip.
.
Complicit Constapo Talibangelical since MMIII
((Some internet wag said "85% of the sound of a Proac at 1/5 the price))
Yea OK lets get real not even close
Maybe 15% at 1/5th the price
I'd say it's more like 90-95% at 1/5th the price. The Proac's have a new address now.
Don't listen to me, I sell 'em.
.
Complicit Constapo Talibangelical since MMIII
Just curious but a front port does not mean it will work better than a rear port - depending on the design. The Audio Note AX Two is rear ported and designed for near wall corner loading - it's also my favorite under $1k with the right front end. Though I grant the Audio Note's may be exceptions to the general front port / rear port guide.
I've found bottom ported speakers the easiest to mate with my room however.
In the case of the rear port, some companies offer a plug for the port if the bass is too heavy in the room. As a hobbyist, I have at least one set of my own that does just that. It is a small rear ported minimonitor that can be changed to a low Q sealed box using the plug. Maybe I just got lucky but the low Q alignment at just over .6 mates well when the speaker is too close to a rear wall and I get to unplug them when the speakers are out on stands. I think a few companies are doing this too.
Does anybody know of a supplier of port tubes that offer mated plugs for them? Those in my own speakers are not WAF approved. She likened mine to molotov cocktails.
Bill
Agreed on the rear port issue; I can think of three reasons why an appropriately designed rear-ported speaker should work better, even when placed close to a wall or near a corner. I like Audio Note's approach in this respect.
Duke
Just curious..what are the 3 reasons? Thanks
Arguments in favor of rear-porting:
1. Any midrange energy emerging from the port will be less audible with the port on the rear than if the port was on the front. Whether or not this is an issue depends on several factors, but in most two-way ported speakers some midrange energy escapes via the port. The longer the port, the more likely that it's a source of coloration (imaging talking through a cardboard tube - the longer the tube, the more coloration; it's actually a bit more complicated, but that's a reasonable approximation).
2. Boundary reinforcement of the port's output is enhanced by the rear port's proximity to the wall - giving you more deep bass energy. A down-firing port usually works even better. Note that not all ported speakers sound good with boundary reinforcement of the port's output - many will sound too boomy. The solution is a port that tunes the box lower than "normal" - in anticipation of such boundary reinforcement. This is the approach Audio Note uses. It can be done with conventionally-tuned rear-ported speakers if you re-tune them to a lower frequency, which usually requires some creative modification of the port (either increasing its length or reducing its diameter) unless the port length is readily user-adjustable.
3. Theoretically it's desirable to have multiple low-frequency sources spaced apart some distance. If you've ever noted a significant change in bass response from moving a speaker a few inches, that illustrates that the room-interaction-induced peaks and dips can change significantly with a small shift in source location. Several researchers advocate multiple low frequency sources in a room, such that they "average out" at the listening position (and pretty much throughout the room). If a rear-ported speaker is toed in a bit, and if the rear port is not at the same height as the woofer, then the locations of these two low frequency sources are displaced relative to one another in all three dimensions. I do not know how much physical displacement of port and woofer it takes to result in an audible smoothing - that probably depends on the room acoustics to a certain extent - but at least with a vertically offset rear port and a bit of toe-in you're stacking the deck in your favor.
Arguments against rear-ported speakers, and my counters:
1. Rear ported speakers won't have good impact because the port's energy is firing in the wrong direction and therefore has a longer path length to the listener. This makes intuitive sense, but the problem is that at typical port tuning frequencies the ear doesn't even register the notes until more than one wavelength have arrived. In other words, the ear is so slow to hear low frequencies that the minor additional path length doesn't make a significant difference. Up close there would be a measurable and audible bass SPL difference from the port being on the rear, but back at the listening position the SPL difference would be negligible (remember, the port's low frequency output is omnidirectional). Boundary reinforcement of a rear-facing port's output can actually increase the subjective sense of impact, assuming the port is tuned appropriately.
2. Rear ported speakers sound boomy if placed close to a wall. This is certainly true in most cases! But when the port starts out tuned with boundary reinforcement in mind, or if the port can be adjusted, if done right the net result is deeper bass extension instead of bass boom.
3. If you place a rear-ported speaker too close to the wall, the narrow space between the port opening and wall will change the tuning. Yes this is true, but we're talking about the wall having to be something like 2/3 of a port radius away for this to begin to happen (and we're assuming the rear of the speaker is parallel with the wall). Also, note that any change in tuning from an increase in effective port length due to wall proximity will be in the direction we'd want to go anyway - the tuning frequency would be lowered (though probably not by very much).
Disclaimer: In case you haven't guessed, I incorporate user-adjustable rear porting into my designs... and I stole the idea of rear porting from Audio Note. In my opinion they have essentially proven the concept, and I don't know why more manufacturers don't use it. There's a free bass lunch out there for low-tuned rear-ported speakers if you place 'em close to the wall.
Duke
I perfer bottoms to rears;)
I presume your speakers with down-firing ports are floorstanders - is this correct?
Have you found the floor surface (carpeted vs uncarpeted) to make a difference?
What general guidelines do you follow in choosing how high to elevate the bottom of the enclosure above the floor?
If any of this is proprietary, of course I understand.
I'll be experimenting with a down-firing port in the next few days, as that's the only way I could shoehorn the port size I want into this particular enclosure.
Duke
I do perfer bottom ports on floorstander You can use larger longer ports distance from floor is a known factor so you can tune for this, bottom loads room best.Has less problems with placement over rear or front.Carpet or hardwood doesnt make so much diferance but for some customers I supply damping pads to place under if floors too live.Distance from floor differs for ea. loudspeaker design I have to test then ajust by ear.Cones blocks all work to lift loudspeakers.Some - are cost for such designs always seems to cost more with a bottom port.Some owners dont get it and remove cones setting port on floor:)
nt
Greetings from the sunny Brønshøj riveria on the banks of the lovely Utterslev Mose
While I dont know retail on the arcs.I would think KCS offers a far better deal for cost outlayed.We have bottom ported floorstanders starting at $2500 pair these have a AMT style driver with 12in fostex woofers.
,,
On critical face value, your discussion especially in respect of pro's of rear-ported somewhat suggests that down-firing ports is much more superior rear-firing port in numerous ways.
Secondly, have you noticed that most concentric designs and horn designs follow a front-firing port design concept? and I think the idea is actually that you 'hear' the port as part of the midrange? I know you said it tongue in check, but there is really no free lunch anywhere. The only argument for a rear-port is boundary reinforcement, but it comes at significant price, the speaker is much more placement sensitive with the associated ill-effects.
Music making the painting, recording it the photograph
Dear TAH,
Your statement that a rear firing port makes the speaker more room sensitive with more ill effects is simply incorrect, why would it do that??
Our experience is that as you move the speakers closer to the room boundaries the effects of the room are reduced rather than the opposite and this applies whether the port is at the front or the back of the speaker, which as it happens that is also concurs with what most of the 1930's research that I have seen.
Sincerely,
Peter Qvortrup
"Our experience is that as you move the speakers closer to the room boundaries the effects of the room are reduced rather than the opposite..."
Let me see if I understand this (for although I use rear-firing ports, I don't claim to know as much about them as you do).
It seems to me that the acoustic environment up close to the room boundaries will be more similar from one room to the next than will the acoustic envioronment out away from the room boundaries. So, placing the port on the rear of the enclosure will put it as close as possible to the room boundaries with proper placement, and therefore give you more consistent low end from one room to the next. Is this correct?
Not sure if you noticed, but elsewhere in the thread I acknowledge that I'm copying you in using rear porting. By any chance have you considered making the port length user-adjustable, for applications where the user cannot take advanage of the corner placement your speakers are tuned for? For instance, a 3" diameter modular flared Precision Port with an overall length of about 9 inches would tune the AN-E to 29 Hz, which I think is its normal tuning frequency. By removing the center section the tuning is raised to about 34 Hz, and by using only the outer flare the tuning is raised to about 41 Hz. The sections can be held together with a single wrap of electrical tape instead of glued together, and the port itself affixed to the enclosure by four small screws - so it's user-adjustable. Hey I'm using your idea - the least I can do is offer you my variation on the theme.
Best wishes,
Duke
Dear Duke,
There are really two issues here,
A.) The placement of speakers close to room boundaries
B.) The subsequent use of the boundaries for bass reinforcement
All the early research I have seen from Western Electric, RCA, Klangfilm and others plus later work done by Philips (the early corner speakers), Klipsch, Voigt & Chave, Allison and even Beveridge, point to the fact that sound waves being propagated from a corner or close to the room boundaries have a far more similar behaviour in different rooms than if the speakers were placed away from the walls in the same rooms, admittedly this work was done in the early days of cinema, but there are no reasons why it should not apply to someone's living room, the laws of acoustics haven’t changed since then to my knowledge, and in my experience this still applies.
Just by way of one example, I took part in an experiment that was sponsored by Bruel & Kjaer, at the main Danish engineering university at Lundtofte in 1981, where 4 pairs of speakers were placed in different rooms in various positions, then measured and listened to, we used a pair of Quad ESL63s, B&W 801, a pair of JBLs the model of which escapes me and a pair of SNELL Type A/IIs.
By a not insignificant margin, the general consensus was that the SNELL A's where least affected by the different rooms when close to the walls and was, by a lesser margin, preferred overall, both on the basis of the measured performance and by the listeners, followed by the Quads, the 801s and the JBLs.
Just for the record, the A/II's are floor loading the woofer, a fact which was considered to be a major reason for their good general in room performance, their excellent dispersion was another.
Our experience clearly demonstrates that provided the speaker has a good, wide and even dispersion window, meaning it projects an almost even hemispherical waveform into the room (something which modern narrow baffle speakers do not, which easily explains why they do not work close to room boundaries) then near wall and corner placement even with a sealed box markedly improves the room to room consistency and general behaviour, I see several reasons for this,
1.) When a sound source (read, a speaker) is placed close to the room boundaries the frequency content of the signal is reflected in a more predictable and consistent manner from room to room, which greatly reduces room interference. When the speaker is close to the side walls it is not possible for the ear to separate the reflected and direct sound from each other, and results in a great reduction in room variability.
2.) What the near side wall placement also does is increase the in room efficiency of the speaker, this is because the off axis energy is now added to the overall sound output and because the frequency energy from a speaker which has good wide dispersion is almost the same at say 30 and 60 degrees, this energy does not alter or skew the overall frequency response, a fact which also explains why speakers with narrow baffles and deep cabinets do not display this ability even if the port is moved to the back of the cabinet, the dispersion is simply too uneven off axis.
3.) Having the port in the back, and dimensioning it to take into consideration the additional loading available from the rear wall/corner/floor (the floor by placing it close to the bottom of the speaker cabinet) not just improves the low frequency extension by up to 18dB, it also allows an unprecedented degree of adjustability of in room bass response. The speaker pressurizes the room in a completely different way in the corner position using this technique when compared to the way a woofer in even a much larger cabinet with either a front facing port or a sealed cabinet
All in all there are many good reasons why near room boundary placement enhances the performance of a speaker designed to be used in this position, so whilst I can see some reasons for why the audio industry standard measurement require free field on axis measurements I believe these were chosen out of convenience and for the sake of having an easily repeatable method, but I think it is overall a no less misleading way of “proving” speaker performance because we all know (and so did the engineers who originally decided on the anechoic measurement technique) that all speakers end up in a room with four walls and floor and a ceiling, so why did they not establish a technique which better reflects that?
My view of this is that as with many other bench mark tests of audio performance that what was sought was not the best way of getting a real measure of performance, but the easiest way of measuring something that could be used as a marketing tool, and off course because the overwhelming majority of speaker manufacturers use this measure to design their speakers they have no interest in rocking the boat or designing speakers which do not conform to the standard tests, because it would mean comparing poorly with their direct competitors, but does the fact that most speaker manufacturers uses the same method to design and measure their speakers mean that this method is the best available or produces the best end results??
If it not the job of the magazines to question the practices of the industry they write about, rather than pander to its need to sell its products, what is their job??
In my view it is the main job of the press to criticize and point out poor practice and that applies not just to audio (may I say here that many brave and committed journalists die every year exposing deplorable practices in many parts of the world and their sacrifices should be recognised and are not remotely comparable to the minor transgressions of their audio brethren), but magazines like Stereophile and I should say for the record that Stereophile are by no means the only or the main culprit here, should be pointing out the weaknesses in the methods used by the industry they are there to be policing on behalf of their readers in the hope/expectation that it would encourage the industry to improve its processes and as a result its product over the longer terms.
I just don’t see this happening, not in the 30 odd years I have worked on my "project", the magazines are almost greater slaves to convention than most manufacturers, they jump every new bandwagon almost before any manufacturers have had time to embrace it, thus forcing most larger manufacturers to embrace technology which in many cases turns out to dud wasting vast amounts o their readers money in the process, not really a commendable record is it?
Wolves should not be game keepers and perhaps this lack of ability/willingness to criticize explains the slow death of most of the printed magazines as readers turn their back to them and start looking elsewhere?
Anyway, enough of this hope it put a little more information on the bone so to speak!
Sincerely,
Peter Qvortrup
It seems to me that the acoustic environment up close to the room boundaries will be more similar from one room to the next than will the acoustic envioronment out away from the room boundaries.I do not believe that this is not borne out in practice, more correctly rooms of dissimilar dimensions will have dissimilar acoustic environments and vice versa. To give an extreme example a room measuring 12 * 18 * 7 room and one measuring 30 * 25 * 20 will have vastly disimilar acoustic xteristics even along room boundaries, specifically the eigentones even along the room boundaries will be vastly different as it is dimension dependent. I can think of a few reasons why having a speaker flush to the wall i.e. on a plane or a close approx, might be beneficial owing to diffraction effects, but that is whole 'nother issue.
Music making the painting, recording it the photograph
Oh I definitely understand that different rooms have different acoustic characteristics, especially in the bass.
I've had the exact same speaker be boomy in one room and then anemic and wimpy in another, when the room dimensions were within about 20% of each other and the relative placement within the rooms as similar as possible, but not close to any walls. In this case, re-tuning the speakers for corner placement and placing them in (or very near) the corners resulted in more satisfactory and consistent bass in both rooms.
What I'm saying is that I think the low-frequency presentation would vary less from one room to the next if the speakers were consistently placed where they'd recieve a lot of boundary reinforcement (like in the corners). This is based on too few observations to draw a definite conclusion, hence my asking Mr. Qvortrup - whose experience with such placement vastly exceeds my own.
On the other hand in my experience soundstaging is more three-dimensional when the speakers are moved out away from the walls, so like most things in audio apparently there are tradeoffs involved.
Duke
A actual citation from that period that I can get hold of in the national library will help and clarify where you are coming from.
Music making the painting, recording it the photograph
Dear TAH,
From my recollection it was not I who made the unsolicited claim about rear ported designs' it was you, so why don't we start by you providing the required references as to why rear ported designs have more room problems and other acoustic ill effects and spend some time analysing that material first, we can then move on to related matters.
I am perfectly happy to provide material to prove my end of the discussion once I have had an opportunity to see the material that backs up your claim.
Sincerely,
Peter Qvortrup
I should have guessed....just another day on the salesman trail...here was I thinking that you will use the opportunity to provide some clarification.Music making the painting, recording it the photograph
Wait you said this:
"but it comes at significant price, the speaker is much more placement sensitive with the associated ill-effects."
I have never heard this from any source except you. Why is it so hard for you ONCE to simply state a book and a page number where you got this information from? You stated it BEFORE Peter made a post.
You made a CLAIM FIRST
He said he would give you the information IF you could simply back up your claim. You are clearly the one weaseling out of it and the fact that the other poster is a manufacturer does not change anything.
You made a claim that should be very easy to back up since apparently you are an acoustics engineer wannabe so why is it so hard now.
I mean I asked you to show me how a horn speaker and a panel were more the same than they were different -- surely you could back up that claim with references but alas BS as usual.
Dear TAH,
Guess what, you are just another arm chair general with no army.
When you make a claim for which there appears to be little or no justification the burden is on you to bring something to the table that backs up what you say, so how about bucking up and backing your negative comments and claim about rear ported designs up, rather than, as usual when challenged, trying to take the fight to someone else's yard to divert attention to the fact that you have nothing by way of support for what you say?
TAH, we have been here before and this is your standard tactic, you make some unsolicited claim negating some aspect of a design, but without even the slightest scrap of evidence to back up what you say, and then you expect me or someone else to take what you say serious?
Sincerely,
Peter Qvortrup
We were actually having an intelligent discussion until joined the thread to offer a sales pitch.
Music making the painting, recording it the photograph
Okay you have now made another claim.
Please show the sale's pitch?
You slag a design with zero evidence but he's at fault and making a sales pitch. What weird little lonely life are you living.
I chose not to use down-firing ports mainly because they are more difficult to access for changing port length, but otherwise have no objection to them for a floorstander. I'm not sure how practical they are for a stand-mount speaker, where you really don't have effective boundary reinforcement. For a stand-mount speaker, rear porting may be the better configuration for taking advantge of boundary reinforcement.
I don't understand what horn loading and concentric (coaxial?) designs have to do with port location. If you're saying that in some cases the port is supposed to contribute to the midrange output, then I'd disagree strongly with that design approach.
There are arguments for a rear-firing port aside from boundary reinforcement, as indicated in my previous post. If the port length is fixed (as is usually the case), then it could well be argued that a rear-ported speaker designed with boundary reinforcement in mind is particularly placement sensitive. On the other hand, a rear-ported speaker whose port length is user adjustable is extremely room-adaptable.
In my experience, the low-frequency acoustic environment changes very significantly from one room to another, so I place a high priority on the ability to make large adjustments to the low frequency characteristics of a loudspeaker. I have encountered rooms where speaker positioning alone could not give balanced-sounding bass, and significant adjustment of the speaker's output was necessary.
Duke
Provided the Speaker stand is designed with rear-port in mind, a downward-firing port gives nothing away to rear-firing port in terms of praticality.
The port length is not infinitely adjustable and there is nothing to stop to a variable length downward or front-firing ports. Therefore, I fail to see how a variable length port provides unique advantages to rear-firing ports. At any rate Kef and Tannoy have used front firing ports very effectively in their coaxial designs in both domestic and profesional applications such that I fail to see any other advantage for rear-firing ports than their ability to take of boundary reinforcement.
Music making the painting, recording it the photograph
Port adjustability is one issue, and might be a nice option to have regardless of where the port is (though a potential issues arises with a front-facing adjustable port; see below). I will concede your point that port length is not infinitely adjustable, but if you have access to a modelling program you can see how much variation in bass response is attained by changing the port length within reasonable finite limits set by the enclosure's dimensions. Offhand I can think of only one manufacturer besides myself who offers adjustable-length ports, but I'm sure there are others.
Port placement is a different issue. In my opinion either rear-firing or down-firing is usually preferable to front-firing. Apparently mine is a minority position, judging from a glance at the marketplace.
Port adjustability is not an advantage unique to rear-firing ports. In my opinion flexibility is maximized when the adjustable port is rear-firing; most of my reasons for this have already been stated but here is another:
Sometimes the room offers too much bass reinforcement, and with a rear-firing port you can reduce the boundary reinforcement by moving the speaker away from the walls. With a down-firing port, you'll still be getting a lot of boundary reinforcement from the floor wherever you place the speakers. So if the goal is maximum adaptability through a combination of speaker placement and port tuning adjustment, I think that rear-firing offers a wider range of flexibility than down-firing.
One factor that I haven't mentioned yet is the damping material inside of a reflex enclosure. For maximum bass you want no damping material, but to minimize midrange coloration through the port you want some damping material. The amount of damping material you need to acceptably minimize midrange coloration is greater with a front-firing port than with a down-firing or rear-firing port. This translates into more powerful low bass from either of these less-conventional formats because of the reduced damping material requirement.
Note that increasing the port length also increases the damping material required to keep midrange coloration acceptably low. So this is another reason why an adjustable port makes more sense on the bottom or rear of the speaker, as less damping material is required with these configurations.
Yes there are excellent speakers with front-firing ports, and probably some lousy ones with rear-firing ports. It's not the biggest issue in loudspeaker design.
Duke
I have been using a pair of Tyler Taylo monitors that are front ported. They are excellent speakers, but found myself plugging the front ports to control a bit of "boom" and to help integrate my sub. I recently picked up a pair of Merlin TSM-MMe's that are sealed and they are much easier to integrate with my sub and they sound marvelous. If you have a small or otherwise difficult room, i would consider a sealed enclosure. My 2 cents.
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