Btw - don't measure TSPs the way the chassis is showed on the picture! You will get wrong parameters.
It must be stable and all venting must be free.
These membranes are not super heavy and suspension not weak. Not sure if it would happen with these, for sure not with a few month storage. But >10 years in a woofer ... I also prefer vertical mounting.
Yes, a blocked vent or even just a vent too close to a boundary will skew TSP measurements, in worst case showinga second impedance peak higher up. Even just holding the driver with your hand will net a lower Qms and mis-shapened impedance peak. Ideally the driver in test should be firmly clamped vertically with several inches clearance from the rear vent and a few feet from front and sides of chassis.
May you please tell which measurement protocol was used please ? Can it be extrapolated for instance you do not have room gain below circa 50 hz.
so, 0.5 meter heigth box. Which mic distance and gating. size of the room and ceilling heigth.
Did you try on floor measurement technic ?
Which is the one in a 3 ways stereo hifi sounded the best according your taste (test) ultimatly (tone and details, as it is hard to know with vented because of alignement choice) ?
so, 0.5 meter heigth box. Which mic distance and gating. size of the room and ceilling heigth.
Did you try on floor measurement technic ?
Which is the one in a 3 ways stereo hifi sounded the best according your taste (test) ultimatly (tone and details, as it is hard to know with vented because of alignement choice) ?
Hope I understood your question correctly.
My room dimensions are LxWxH = 19.4 feet x 9.5 feet x 10feet.
Room gain depends on longest length of your room in this case 19.4 feet.
We can have a rough estimate using BDBS excel sheet or even winisd's basic linkwitz transform.
Yes it fairly matched simulation with my reality. Please note there are other factors that may change or cause a null in the rising area of room gain which may mislead you to believe there is no room gain.
Actually you could practically see how much room gain slope you are getting with some already exiting subwoofer with known roll off and see how actually rolls off in your room. Then you could extract the differential response from both curves.
Measurement was just using omnidirectional mic from listening position. No gating.
Did you try on floor measurement technic ? No, since I needed in room response.
Sealed to me sounds miles ahead(fast, precise, deeper) compared to ported as I could never get all the drivers work well together, as there seem to have too much seat to seat variation and phase related issues with ported.. Because of 24db/octave roll off of the ported below tunnin, it might be very difficult to get great response down to 10hz without exceeding XMAX or getting a driver that can be tuned very low. Also I don't use DSP.
Thanks for your experience. Question was for IamJF as well.
I try to understand about in room measurement and voicing for the bass, in particular to where is the mic (or if multiple positions technic) in relation to the room modes : if for instance the mic is inside a deep or peake pressure area.
For passive filters, I have hard time to know if one should better measure inside or outside (on floor with far boundaries or in a big rod above the floor).
I try to understand about in room measurement and voicing for the bass, in particular to where is the mic (or if multiple positions technic) in relation to the room modes : if for instance the mic is inside a deep or peake pressure area.
For passive filters, I have hard time to know if one should better measure inside or outside (on floor with far boundaries or in a big rod above the floor).
Last edited:
Well I think it's still a open debate of number positions to measure accross seats or tightly spaced measurements around MLP. If your receiver supports multiple profiles then you could save multiple profiles and compare which works best for your situation and/or switch based on need basis. I would generally measure tightly around main LP as I am greedy and want best to myself. 
Regarding measuring around peak pressure area, I would do it to identify and optimal placing the acoustic panels around hotspots.
Regarding measuring around peak pressure area, I would do it to identify and optimal placing the acoustic panels around hotspots.
First sentence: "I did some measurements today of these 3 drivers in closed volumes. In my measurement room, 0,5m distance groundplane - so there is a little room influence left, but good enough for a comparison. Level is corrected for 1m freefield."
No gating. Room is very well dampened, at 0,5m groundplane you don't measure roomgain in here.
The 12" behaves best at higher frequencies - I would only use that one for very high quality 3way. But I didn't do proper 1:1 listening comparisons, that's a lot of work. The 8" for 3ways up to 200-250Hz and the 10" as woofers.
And I never use vented enclosures for my designs - don't do designs you know it's flawed in the beginning ;-)
Last edited:
Never tried. Probably not bad but compareable low sensitivity and only 2" coil. Also "normal" Xmax. Strange frequency response measurement.
Probably goes deeper in a big volume - but don't see a use for my projects.
The reason I consider NE315W is based on my very good experience with NE225W and NE265W. There is not many 12" wwofers suitable for ~300Hz crossover. 32W T00 revelator is excellent in closed box and I expect T01 and T00to be great as well. But the price..... So I am looking for 12" ~300eur. To be frank, I do not like the sound of SB woofers, though I admit some of them might be ok for subwoofer duty (Fc <100Hz). SS 32W Rev is my reference here. The reason I consider SB34NRXL is your experience. I guess I will have to give it a try and hear for myself.
My usecase is home hifi, so sensitivity ~90dB and 2" coils are fine.
My usecase is home hifi, so sensitivity ~90dB and 2" coils are fine.
I would like to know if a SC4 or SBB4 alignement as a start before passive filter tweaking (group delay) with near 18 db slope in the low end are not good enough as a vented VS closed Qtc 0.7 ?
When one is looking at the problem of the loss according the driver I have the felling most of the designers makes too much small enclosure for vented hence, perhaps, the barel sound. But I do not know. Put some dampening inside and you can increase up to 10% to 20% the volume box, how to know you succeeded to load your bass driver with the good volume and the room gain ?
From a theorical point of view and even talking about price, I have a problem with the SB34 datasheets : the highish voice coil inductance and the Vas (not a bad thing for this last in sound quality target).
@IamJF , I do not understand your measurement from a candid point of view: what gating, what signal did you inject, what material did you use (usb mic from the pc or soundcard), nore I have the volume of the room and so on. It doesn't mean at near iso parameter your experiment is not usefull, indeed you can have an idea at iso perimeter of the experience. I would more focus on the subjectiv listening experience here than the measurements we almost know nothing. I readed between the lines @Draki asked for a reason I surmise the impedance measurements.
It is not a judgment, i am a noob (perpetual learning) but I am wondering with a 12" I have and used by some at different Vb fromm designers. No logic behind. I see behind the effect of Ql on Vb choice (volume box). For illustration if some are designing around Ql=7, I assume as a beginner (perpetual) point of view a PA driver with fabric suround and fabric mushroom have more loss and the volume box should be higher as the predicted low end (beginning of the f3 dive).
And I am not confident about that with the SB34 due to their high inductance (mH) |edit]for passive designs, for something that snap if the sealed designs are the benchmark. Understand it as : most of the vented are flawed due to the complexity of measurement and Vb and port designing. For me, saying you have a damped room for the bass means nothing due to the bass frequencies involved!
That's my feeling.
When one is looking at the problem of the loss according the driver I have the felling most of the designers makes too much small enclosure for vented hence, perhaps, the barel sound. But I do not know. Put some dampening inside and you can increase up to 10% to 20% the volume box, how to know you succeeded to load your bass driver with the good volume and the room gain ?
From a theorical point of view and even talking about price, I have a problem with the SB34 datasheets : the highish voice coil inductance and the Vas (not a bad thing for this last in sound quality target).
@IamJF , I do not understand your measurement from a candid point of view: what gating, what signal did you inject, what material did you use (usb mic from the pc or soundcard), nore I have the volume of the room and so on. It doesn't mean at near iso parameter your experiment is not usefull, indeed you can have an idea at iso perimeter of the experience. I would more focus on the subjectiv listening experience here than the measurements we almost know nothing. I readed between the lines @Draki asked for a reason I surmise the impedance measurements.
It is not a judgment, i am a noob (perpetual learning) but I am wondering with a 12" I have and used by some at different Vb fromm designers. No logic behind. I see behind the effect of Ql on Vb choice (volume box). For illustration if some are designing around Ql=7, I assume as a beginner (perpetual) point of view a PA driver with fabric suround and fabric mushroom have more loss and the volume box should be higher as the predicted low end (beginning of the f3 dive).
And I am not confident about that with the SB34 due to their high inductance (mH) |edit]for passive designs, for something that snap if the sealed designs are the benchmark. Understand it as : most of the vented are flawed due to the complexity of measurement and Vb and port designing. For me, saying you have a damped room for the bass means nothing due to the bass frequencies involved!
That's my feeling.
Last edited:
did you see it : https://faitalpro.com/en/products/LF_Loudspeakers/product_details/index.php?id=151050115 ? Vas is not so high relativ to SB or SS.
This SB34 is crazy insane driver all the way up to this little distortion peak around 700 Hz.
Oh wait...it is so low that even that is not importanat at all.
Amazing unit...beats 2 x WO24 Satoris anyday... and costs less...
Now 4 of my SB23NRX babies look pathetic in comparison.
Oh wait...it is so low that even that is not importanat at all.
Amazing unit...beats 2 x WO24 Satoris anyday... and costs less...
Now 4 of my SB23NRX babies look pathetic in comparison.
We are talking about the measurements here - not feelings. You can focus on the subjectiv listening experience probably in a new thread? I started this to show the technical behaviour of these SB Acoustics drivers. Feel free to add measurements of other drivers in comparison!
A meaningful listening comparison of bass drivers in a closed room is pretty hard to do - cause moving the driver 20cm in the room gives a different frequency response. Did that a few times but I never was sure how much influence came from the room and the driver.
I already wrote - no gating. Sine sweep. Audio Precision measurement system, Earthworks M50 mic, Banchmark AHB2 amp. Look it up. You can't measure 0,05% THD with a USB mic
The room has 60cm absorption on the backwall and BCA Absorber on ceiling an the other walls. 20cm moveable absorber walls to devide it. It's a simple measurement room with reflecting floor - perfect for ground plane measurements. With the right positions you get very little influence.
You can trust these measurements.
These vented enclousure alignements are rather theoretical - how many ported speakers did you built already? As soon as you put some dampening material in the box everything changes anyways. Build a prototype, do some tests. And then comes the room. TSP changes with power and excursion.
Don't think to much about the second decimal place in acoustics
At least it's high enough that I would stay away from this area.
The ScanSpeak 12" can also do that performance but is more expensive.
Looking forwart to a Purify 12" ... but that's probably 3-4times the price ...