Magnepan LRS Speaker Review

[snapsc]

I see it this way: if you own Maggie’s and like them, then the measurements and review shouldn’t phase you.

On the other hand if you don’t own Maggie’s and because of the review wouldn’t consider auditioning them, then you may be missing out on something.

 

[Joppe Peelen]

I see it this way: if you own Maggie’s and like them, then the measurements and review shouldn’t phase you.

On the other hand if you don’t own Maggie’s and because of the review wouldn’t consider auditioning them, then you may be missing out on something.

i think measurements are very useful , besides listening of course. then still if you like them even if they measure like shit. who cares. you have to listen to them if it makes you happy ! go for it ! as long as the price is decent and they dont pretend all kinds of snake oil things
and well even if i would never buy them here in the netherlands... the price in the US is really decent.

 

[KaiserSoze]

Hi

A simple question. Is the LRS the best effort by Magnepan? What if it were a not so good example of what Magnepan can do ? I am awaiting measurements from other dipoles to form an opinion. This is the first and only dipole so far reviewed by Amir,

There are some conclusions that are fully valid for fundamental, analytical reasons, without taking any measurements. In particular, if the woofer and tweeter are located side-by-side and the crossover is such that the wavelength at the crossover frequency is less than 2 x the horizontal spacing between the woofer and tweeter, the tonality will not be consistent across the forward, horizontal radiation space. If you listen to a speaker of this sort and you use some music with snares or similar, and you listen carefully to the snares as you move from side to side in the forward, horizontal radiation space, you will notice that the snares sound brighter in some locations and weaker in others. You can take this effect for granted with any speaker that it designed this way. It is okay for the woofer and midrange to be located side-by-side if, and only if, the wavelength at the crossover point is at least twice greater than the horizontal spacing between the woofer and the tweeter. In general this means that the woofer must not be operated any higher than roughly 300 to 400 Hz.

 

[StefaanE]

If a dipole speaker is mounted outdoors on a tall pole and measurements are taken of just the front hemisphere, shouldn't it measure much the same as a good forward-radiating speaker?

As far as I understand the argument, the reflections from the back wall are an integral part of the transmission chain, and hence dipoles should be measured in a room and in a position that generate the right reflections. But in my humble opinion (as owner of a room with windows, and furniture that severely restrict speaker positioning) this means these speakers will only sound good by accident, or when the room has been designed to specifications (which don’t seem to exist).

 

[NTK]

Ok so i stopped reading major problem i got is... its not a sphere... a sphere indicated a point source and extrapolates from there. a big planar speaker is far from a point source.
...

The mathematics is not limited to describing a point source. It only uses the spherical coordinate system (in this case). You can take a look at this paper to see an example of the application of this method to characterize the sound radiation pattern from a vibrating rectangular plate and the comparison to the theoretical prediction.
https://www.xlrtechs.com/dbkeele.co...ull Sphere Measurements Using HELS Method.pdf

 

[bunkbail]

thats funny , a viewer well dont take my word for it. although this one i think im in the save , puss agrees

Hi and welcome to ASR! I'm one of your viewers as well though I've never commented on any of your videos. I found your channel thru diyaudio after seeking for some infos about BG and Sounderlink planars .

 

[Joppe Peelen]

There are some conclusions that are fully valid for fundamental, analytical reasons, without taking any measurements. In particular, if the woofer and tweeter are located side-by-side and the crossover is such that the wavelength at the crossover frequency is less than 2 x the horizontal spacing between the woofer and tweeter, the tonality will not be consistent across the forward, horizontal radiation space. If you listen to a speaker of this sort and you use some music with snares or similar, and you listen carefully to the snares as you move from side to side in the forward, horizontal radiation space, you will notice that the snares sound brighter in some locations and weaker in others. You can take this effect for granted with any speaker that it designed this way. It is okay for the woofer and midrange to be located side-by-side if, and only if, the wavelength at the crossover point is at least twice greater than the horizontal spacing between the woofer and the tweeter. In general this means that the woofer must not be operated any higher than roughly 300 to 400 Hz.

Most monitors cross at 3 khz.... a maggie does that much lower . while even being closer to the woofer then any dome? not ,many domes can cross at 1200hz-1400hz so it should be better then most domes crossed over. so if you got a 8 inch woofer.. thats like 20.4 cm diameter, most of the magnepans are around 24 cm wide (of witch driven area is even smaller) and of witch 3 to 4 cm is the tweeter (yes the tweeter is big compares to a dome thats why the top end still beams) @ 7khz , and above even worse. but the crossover region is no problem, its much better then most speakers.

 

[Joppe Peelen]

The mathematics is not limited to describing a point source. It only uses the spherical coordinate system (in this case). You can take a look at this paper to see an example of the application of this method to characterize the sound radiation pattern from a vibrating rectangular plate and the comparison to the theoretical prediction.
https://www.xlrtechs.com/dbkeele.com/PDF/Keele (2006-10 AES Preprint) - Full Sphere Measurements Using HELS Method.pdf

but does it compute ? since it will not if you measure up close.?


{EDIT}apparently it does compute. an i did not know how the whole klippel system works, still shocked by the findings though

 

[Joppe Peelen]

Hi and welcome to ASR! I'm one of your viewers as well though I've never commented on any of your videos. I found your channel thru diyaudio after seeking for some infos about BG and Sounderlink planars .

thats nice to hear. its a small world !!! i should post more on DIyaudio and less on facebook since i learned soooo much at DIyaudio. and well nothing at FB or youtube. aaah well. i hope you enjoy all the failures. and sometimes a win

 

[LTig]

Other than stated by several posters I do think that @amirm has done enough measurements to describe the behaviour of the LRS in anechoic conditions. Even enough to somehow find the cause of the 'magic' sound. We just don't have enough knowledge (or done enough work) yet how to correctly interpret the results into how the LRS sounds in a room where it is optimal positioned. Clearly neither the Klippel's on axis FR nor @John Atkinson 's FR show directly what one would expect to hear in an optimal room, especially below Schröder.

Where the LRS is different compared to a conventional box speaker:

• Almost no dispersion at +/- 90 degree
• At 180 degree same dispersion as at 0 degree but with 180 degree phase shift

Surely this kind of dispersion leads to a very different in room response compared to a conventional box speaker. IMV this is not a flaw but a characteristic feature. No side reflections should lead to less room influence, OTOH throwing the same sound at 180 degree phase shift leads to more room influence above Schröder. While I had MG 1.6 I did not treat the room but I can imagine that treating the front wall to dampen reflections above Schröder may reduce room influence. Less room influence is good for lively rooms or when one wants to hear what's on the record.

• Tweeter and woofer side by side with too large distance.

This is a major flaw and leads to a bad horizontal dispersion. It could be improved by using a DSP crossover with very steep flanks (48 dB/octave) to minimize the region where the flaw is audible.

• It looks like a line source but it isn't. It neither goes down to the bottom nor to the top of the panel. Nor is it shaped as a vertical curve which improves the sound field over distance (see @Floyd Toole's book where different line sources are compared).

I consider this to be a major flaw as well because there are only disadvantages (extremely narrow vertical sweet spot due to the vertical size of the tweeter) but not the (desired) behaviour of a true line source. Still a narrow vertical dispersion reduces room influence and may have a positive effect in very lively rooms.

• Large moving area means for the same SPL excursion of the foil is lower compared to a conventional box speaker.

This should lead to low distortion since distortion increases with excursion. However with magnets on one side of the foil the membrane does not move in a constant magnetic field which increases distortion - at least in the low frequencies where excursion is high. I have no clue which effect is stronger.

• Acoustic shortcut in the bass

This is a flaw, but one which cannot be circumvented. Some posters claim that placing the LRS on the floor dramaticely improves bass compared to the measurements taken off the floor. This cannot be true. Most of the bass gets lost via the short side. There will be an improvement but only a minor one. To get better bass you must place the LRS at such a distance to the front wall that the wave leaving the back of the panel reflects such at the front wall that it sums up with the wave leaving the front of the panel at a frequency where the shortcut has damped the far field SPL by 6 dB.

• Very low sensitivity (~78 dB when one ignores the unwanted hump at 250 to 900 Hz)

This is not a flaw per se but buying a cheap speaker which then requires tons of stable power at 4 Ohm is not very economical. We have seen that investing most of the budget into the speaker is the best approach to good sound for less money. The hump though is a major flaw.

My story:

As I wrote elsewhere I owned MG 1.6 for 13 years and then switched to active 3 way studio monitors (later accompanied by a sub). As far as I remember the sound of the MG 1.6, driven by the mighty Denon POA6600 monoblocks, was:

• muddy mid bass
• no deep bass (which I did not miss because I had never had speakers before which were able to deliver deep bass)
• big soundstage but very fuzzy
• bad dynamics
• very smooth upper mids
• very forgiving with bad recordings
• nice for classical and jazz
• people who had a listen usually liked them, some a lot

The switch to a studio monitor happened when a colleague asked me for help choosing good speakers. He liked the MG1.6 but did not want panels due to optics. We went through a lot of hifi shops and finally into one which had a pair of the biggest Gaithain's playing. That was the best sound I've ever heard, but far out of financial reach. SInce these were studio montiors we visited the local musicians store and there he finally decided to get the K&H O300D.

I liked them as well and when some 6 months later I saw a very good offer on Ebay I could no longer resist and bought them on the spot. The first thought which entered my mind when I listened to them in my room was: "I did not know the Maggies were sooo bad!"

 

[Joppe Peelen]

The mathematics is not limited to describing a point source. It only uses the spherical coordinate system (in this case). You can take a look at this paper to see an example of the application of this method to characterize the sound radiation pattern from a vibrating rectangular plate and the comparison to the theoretical prediction.
https://www.xlrtechs.com/dbkeele.com/PDF/Keele (2006-10 AES Preprint) - Full Sphere Measurements Using HELS Method.pdf

whoo thats going above my paygrade but i cant seem to find them mentioning line sources in any might miss something but not the same rules apply so i dont think you can just use the same formula. and hope for the best. they are really different.

 

[NTK]

but does it compute ? since it will not if you measure up close.?

I'd suggest you look up the theory on nearfield acoustical holography (NAH). Earl Williams' book is a good start.
https://www.elsevier.com/books/fourier-acoustics/williams/978-0-12-753960-7

 

[KaiserSoze]

Your assumptions are generally not correct. The marketing photos are usually generated by buying stock images of beautiful homes and photoshopping the speakers into them. This is why you don't see cables, interconnects, other gear, etc in these shots. It would be a huge expense to take speakers into people's expensive homes to photograph them the way you imagine. I know this because I worked with a number of audio/electronics companies to get their "lifestyle" images for our website and they would give me the photoshop files with the layers clearly showing the stock room with no electronics and the other layers with pictures of gear.

The Magnepan site is decidedly low budget, resembling what the web looked like in ancient times. The pictures as such are real and likely customer ones. Here is the one I showed again:

The seating position is where the camera is placed. It is a U-shaped sofa. So definitely real. And definitely asymmetrical.

Compare that to typical photoshopped marketing image:

No equipment rack. No way to get cables to those speakers without ruining this look, etc.

Bottom line, the assertion was incorrect. Every speaker manufacturer likes to have customers use symmetrical spaces. There is nothing unique about Magnepan.

That's a bad Photoshop. Not that I know much about using Photoshop. I don't. But the reflections that were added to the outer sides of the speakers, to make it look realistic, do not look right to me. In the reflections, the horizontal lines in the wainscoting on the wall should not appear parallel. Near the top of the speaker, those diagonal lines in the reflection should be nearly flat, possibly even angled the other way. Additionally, in the reflection on the left speaker (your left), near the far edge of the reflection (toward the rear of the speaker) you see a vertical feature of the wainscoting that you do not see on the wall itself. Owing to the curvature of the side, as evidenced by the curvature of top edge of the side, the angle between the viewpoint (the camera) and the reflective surface is extremely shallow (i.e., the kind of angle where you can use the radian angle value as an approximation for its sine). As such, that vertical feature in the reflection should be plainly visible on the wall, immediately adjacent to the reflection.

 

[KaiserSoze]

except for nearfield

Is there a complete thought in there somewhere?

 

[Joppe Peelen]

Other than stated by several posters I do think that @amirm has done enough measurements to describe the behaviour of the LRS in anechoic conditions. Even enough to somehow find the cause of the 'magic' sound. We just don't have enough knowledge (or done enough work) yet how to correctly interpret the results into how the LRS sounds in a room where it is optimal positioned. Clearly neither the Klippel's on axis FR nor @John Atkinson 's FR show directly what one would expect to hear in an optimal room, especially below Schröder.

Where the LRS is different compared to a conventional box speaker:

• Almost no dispersion at +/- 90 degree
• At 180 degree same dispersion as at 0 degree but with 180 degree phase shift

Surely this kind of dispersion leads to a very different in room response compared to a conventional box speaker. IMV this is not a flaw but a characteristic feature. No side reflections should lead to less room influence, OTOH throwing the same sound at 180 degree phase shift leads to more room influence above Schröder. While I had MG 1.6 I did not treat the room but I can imagine that treating the front wall to dampen reflections above Schröder may reduce room influence. Less room influence is good for lively rooms or when one wants to hear what's on the record.

• Tweeter and woofer side by side with too large distance.

This is a major flaw and leads to a bad horizontal dispersion. It could be improved by using a DSP crossover with very steep flanks (48 dB/octave) to minimize the region where the flaw is audible.

• It looks like a line source but it isn't. It neither goes down to the bottom nor to the top of the panel. Nor is it shaped as a vertical curve which improves the sound field over distance (see @Floyd Toole's book where different line sources are compared).

I consider this to be a major flaw as well because there are only disadvantages (extremely narrow vertical sweet spot due to the vertical size of the tweeter) but not the (desired) behaviour of a true line source. Still a narrow vertical dispersion reduces room influence and may have a positive effect in very lively rooms.

• Large moving area means for the same SPL excursion of the foil is lower compared to a conventional box speaker.

This should lead to low distortion since distortion increases with excursion. However with magnets on one side of the foil the membrane does not move in a constant magnetic field which increases distortion - at least in the low frequencies where excursion is high. I have no clue which effect is stronger.

• Acoustic shortcut in the bass

This is a flaw, but one which cannot be circumvented. Some posters claim that placing the LRS on the floor dramaticely improves bass compared to the measurements taken off the floor. This cannot be true. Most of the bass gets lost via the short side. There will be an improvement but only a minor one. To get better bass you must place the LRS at such a distance to the front wall that the wave leaving the back of the panel reflects such at the front wall that it sums up with the wave leaving the front of the panel at a frequency where the shortcut has damped the far field SPL by 6 dB.

• Very low sensitivity (~78 dB when one ignores the unwanted hump at 250 to 900 Hz)

This is not a flaw per se but buying a cheap speaker which then requires tons of stable power at 4 Ohm is not very economical. We have seen that investing most of the budget into the speaker is the best approach to good sound for less money. The hump though is a major flaw.

My story:

As I wrote elsewhere I owned MG 1.6 for 13 years and then switched to active 3 way studio monitors (later accompanied by a sub). As far as I remember the sound of the MG 1.6, driven by the mighty Denon POA6600 monoblocks, was:

• muddy mid bass
• no deep bass (which I did not miss because I had never had speakers before which were able to deliver deep bass)
• big soundstage but very fuzzy
• bad dynamics
• very smooth upper mids
• very forgiving with bad recordings
• nice for classical and jazz
• people who had a listen usually liked them, some a lot

The switch to a studio monitor happened when a colleague asked me for help choosing good speakers. He liked the MG1.6 but did not want panels due to optics. We went through a lot of hifi shops and finally into one which had a pair of the biggest Gaithain's playing. That was the best sound I've ever heard, but far out of financial reach. SInce these were studio montiors we visited the local musicians store and there he finally decided to get the K&H O300D.

I liked them as well and when some 6 months later I saw a very good offer on Ebay I could no longer resist and bought them on the spot. The first thought which entered my mind when I listened to them in my room was: "I did not know the Maggies were sooo bad!"

Thats a nice write up !!! read it a few times ! although i dont agree on maggies being bad. Gaithain'? never heard of them since called monitors i thought some , studio monitors... but they are not. they are coaxial, i do agree very pleasing , fullranges or coax every now and then, they can sound really nice. never heard this pair though

If i may add some of what i think.


- Distance tweeter woofer. is 7 mm, and crossover is half that of any monitor, should not be any problem. the fact the tweeter is rather wide compared to a dome might be a problem ! and beams

- The fact it does not look like a line source, and maybe you meant that is it should go to the ceiling. and it does not.

- Acoustic shortcut is just how open baffles work just like the dispersion being almost 0 @ 90 degrees. its the same problem.. although i dont see them as a problem. an open baffle might not PUMP as hard as a closed speaker, allot of people like them, and weirdly enough this is how many of the beloved drum solos are recorded with the most wanted mic... neuman U87 , mostly used as a dipole..
cool you mentioned the hump , also to make use of the back wave, you would have to need more then 3.5 meter behind the speaker hihi thats allot for a small speaker.

- Distortion.
Finally someone that understands it go big or....... have more distortion

- Low sens
Very true, glad you dont see that as a downside, im not doing marketing for magenpan but i am always wondering why people want high sens... since if you do go active.... nothing matters. and if not if you manage to make a complete set with low sens... well.
Everyone can afford a powerfull amp nowadays with class d 4 ohm is not weird, and especially in class D they like 4 ohms so even 100 euro class D modules will make them sing loud enough. i even used the 15 euro boards on a ESL63 no difference in measurements either.

By the way being a cheap speaker does not change a thing. even the more expensive ones are 4 ohms. (and same efficiency according to them 87dB at 500 of course, 2.85 volt into 4 ohm so 2 watt not 1) so you still might need to use the same amp, since they are not much more efficient. maybe they can handle a bit more power though. in the end they all have the same Xmax (at east all the maggies i've seen) so what they could have done is doing the base in parallel.... and gain 3 db.. but then again the tweeter cant match so they did not and chose for more power handling. in the end the x max stands for a max SPL no matter how you reach it, if they would be more efficient they would stay play as loud at max volume as they would with ****** efficiency. except they are a bit more rugged and the tweeter matches up without to or even any padding


I have both studio monitors and planars, and occasionally ESL's and although i love them i would not mix on them. mainly because i know how they sound compared to other speakers. and either bad or good. i make somethign to be used for well.... the other kind of speakers. besides that, doing editing i prefer doing it near field. and not on dipoles love them... but not for work ! kind of have to hearing what they are hearing unfortunately.

 

[Joppe Peelen]

Is there a complete thought in there somewhere?

Well the thought was, its not about being open baffle or not so much. but being a line source. mseauring a needle point is much easier then measuring huge membrane that does lows and heighs. since the lows will reach the mic. and the highs wont.. so you get a weird result. you cant do it. close by.

 

[KaiserSoze]

Ok so i stopped reading major problem i got is... its not a sphere... a sphere indicated a point source and extrapolates from there. a big planar speaker is far from a point source.
its so different in many ways. you cant use a measurement system based on a point source. first of, a point source drops 6 db every doubling of distance an line source does only 3. so your low efficient line source 80dB will be as loud as a 83dB point source at 2 meters. after that the line source will lose 3 dB less over the point source when you double the distance. and that adds up allot !! at 4 meter the low eff line source is 3 db louder...
(if it is a true line source)

true line source is the next problem interfering with measurements derived from a spherical speaker. a line source tweeter measures up close maybe straigh. a little further there is much more low end compared to top end since only the direct sound reaches you and the rest is delayed . some is out of phase and canceled out. so you end up with much more lower frequencies. it also created a a nasty sort of comb filtering if you dont listen exactly in the middle of that semi line source shown in the picture here from Bolsersts (diyaudio) there are 3 line sources. one of 20cm 60cm and 180cm
then on the right you can s ee what happens if you listen on axis or 10 cm up or down, or 20 cm up or down.... a semi line source gives rahter pooo results. a 180cm one does rather nice. so if the LRS are measured like a point source close by you get some major weird results.

picture 2 result of the same 'line sources' but what it does to distance.

so if they where measured near field....... you get the result you see in pic 2


it also makes clear that small planar speakers are far from ideal, maybe cheap but most certainly shit compared to huge ones at least long ones

To be direct you are not writing in a manner sufficiently precise for other people to comment on what you say. In particular, "...its not a sphere... a sphere indicated a point source and extrapolates from there. a big planar speaker is far from a point source...."

What exactly do you mean when you say, "...a sphere indicated a point source ..."? Implicitly you are saying that if the radiation source is not a point source that it is not valid to represent the radiation pattern using magnitude values at points on the surface of a sphere. This is what you seem to be wanting to say, but you didn't give any reason why this would not be valid. I don't know why this wouldn't be valid irrespective of whether the radiation source is or isn't a point source. Why would it be necessary for the distance from the surface of the sphere to the radiation source to be a singular distance in order for this to be valid? The explanation for this seems to be missing from what you are saying. To me at least, but I'm not certain I understand what you're saying. If I understand you, this is essentially what you are arguing, that the distance from the surface of the sphere to the radiation source would need to be singular before it would be valid to capture/represent the radiation pattern using magnitude at points on a spherical surface. This seems to be essentially what you are saying, but I did not see anything in the way of and explanation for this perspective.

If the radiation field/pattern is represented on the surface of a sphere with a given radius, and that sphere is replaced with another sphere with radius twice as great, the energy density will change as the change in surface area. The area of a sphere scales as the square of the radius, thus if the radius doubles, the area will increase by a factor or four, which means the energy density at the surface will decreased by a factor of four. As Amir explained (not that I understood all of it ...) the measurements are taken at points on the surface of a sphere, at a particular distance that is the radius of that sphere, and because the measurements are taken at points on the surface of a sphere, it is possible to extrapolate to other spherical surfaces with different radii. Where it gets complicated is with extrapolating to spheres that are smaller than the sphere where the measurements are taken. It is over my head to understand how this is possibly done if the source isn't a point source, but as Amir pointed out, there are not any speakers that are true point sources. The great majority of the speakers he measures are two-way speakers with the tweeter mounted in a waveguide and with a port on the front or rear or a passive radiator on the rear. These are not point sources. And if the physical size of the non-point-source radiator were ordinarily a problem for taking the measurements, he would have had problems with some other speakers he has measured.

 

[CDMC]

The math doesn't care any more than a Dyno would care what engine technology it is measuring the horsepower and torque for.

Hey everyone Amir made a mistake. Now we can't trust anything he ever says again. For those who are sarcastically impaired, the foregoing was sarcasm.

A dyno measures torque. Horsepower (or KW output) is calculated from the torque and RPM.

 

[KaiserSoze]

most dipoles are not as large as a planar magnetic and i think there is where it goes wrong to be honest. if you would not need 4 times the amount of surface area to get the same low end you could measure them up close... if not.... you cant measure them up close. for instance you could measure a dipole woofer nearby if it has 20mm xmax but what if the woofer had only 4 mm ? they might have used 5 of them to achieve the same. but that does mean you cant measure them up close anymore and have a decent picture since it does not resemble a point source very much anymore for allot of frequencies.

I appreciate your tone of civility, which sets an example for me to follow. However, I am having trouble following what you are saying. I think you are burying a lot of assumptions by taking things for granted when you say what you say. People often do write in this manner, where the worthy points that they are making, that might be deemed controversial, are the things that are not overt but that are only discoverable by digging into the statements that were made, to find the underlying assumptions.

For example, I think you are saying that you cannot measure planar magnetic speakers up close. This seems to be your major point at the early part of the first paragraph, but instead of saying this directly and explaining why you believe it is true and the conditions/practices that are required in order to take proper measurements of the low-frequency response of large speakers, you said this by way of insinuation: "...if you would not need 4 times the amount of surface area to get the same low end you could measure them up close..."

And I made some effort to understand the second half of that paragraph, starting with the "for instance ...", but I decided fairly quickly that it was going to be too much work to figure out what it meant so I stopped trying.

Please understand that if this comes across to you as rude, this was not my intent at all. There is probably a better way for me to have said what I said, but at this moment this was the best I could do.

 

[CDMC]

This analogy actually works the other way too. The engine technology can be the same, but the output method will make a substantive difference. Dyno an AWD car on a 2 wheel dyno and you won't get accurate results. Dyno one wheel of a car with an open differential and you won't get accurate results. You'll get *results* and you can probably tell something about the vehicle and the engine and even estimate the power in some respect or another, but you can see why someone would question things. I'm not suggesting your measurements are wrong. I'm just in the camp of people wondering if there's more to measuring different kinds of speakers.

Actually you will get accurate and consistent results of wheel power from a specific dyno, as that is what a wheel dyno measures, power to the ground. Different wheel dynos measure and calculate power differently resulting in variances depending on which you use. You have to extrapolate to estimate engine horsepower, as different drivetrains have different losses. Usually the extrapolation is done by comparing the wheel dyno numbers of a stock vehicle to the factory power numbers and using a power factor. It is very inexact for calculating actual engine horsepower, but a great tool for measuring modification and their improvements (or detriments).