[ratm]

I eagerly purchased a HTD Level 3 center channel with these specs...


Max. Power Handling: 150 watts

Frequency Response: 45 Hz - 40 kHz

Impedance: 8 ohms

Sensitivity: 89dB

Voice Coil: 1.5"

Dual 6.5" woofers with a Ribbon Tweeter

Shielded Magnet: woofer: 14 + 11 OZ; tweeter: .7 OZ neodymium

Crossover: 3rd order at 2500Hz

Dimensions (HxWxD): 8.3" x 23.25" x 9.5"

Weight (per piece): 26 lbs


I am replacing a Jamo Center 100 that has these specs...


System Type 2-way closed shielded

Woofer (mm/in) 2 x 95 / 3¾

Tweeter (mm/in) 25 / 1

Power (W, long/short term) 70 / 100

Sensitivity (dB, 2.8V/1m) 88

Frequency Range (Hz) 100 - 20,000

Impedence (Ohm) 8

Weight (kg/lb) 1.7 / 3.7

Product dimensions (mm/in, HxWxD) 112 x 300 x 93 / 4.4 x 11.8 x 3.7

Overall dimensions (mm/in, HxWxD) 112 × 300 × 112 / 4.4 × 11.8 × 4.4


I am using a Sony STR-DG710 to push these. I most definatly will be replacing this AVR in the future but finances could not afford me to purchase everything I wanted. I do have a solid plan though. At any rate, I am finding that I have to turn the volume up on the new much larger HTD center than the old one. I would think that since the HTD has a higher sensitivity it should be the opposite. Correct?

 

[jettore]

It's may be a difference in sensitivity. As far as I have read, there are 2 ways to measure sensitivity.


1-W SPL :The reference sensitivity of a driver with a 1 watt signal and measured at 1 meter as a sound pressure level (dBSPL).


2.8-V SPL: The reference sensitivity of a driver with a 2.83 volt signal and measured at 1 meter as a sound pressure level (dBSPL).


The Jamo says it is measured using the 2.8v method. The HTD does not specify what method is used so it may be using the 1 watt method. I think 89db from the 1 watt measurement will be less sensitive than the Jamo with 88db at 2.8v.


That could be one explanation. There could be other factors too. Did you put the new center in the exact same location? Does the Sony have auto room correction and if so did you run it again with the new speaker?

 

[Rasterfarian]

2.8 volts across 8 ohms is 1 watt. Since they're both 8Ω speakers, there's no difference.


AFAIK, "1 watt" speaker sensitivity measurements are all actually done at 2.8 volts, thus a 4Ω speaker will look like it's 3dB more sensitive (because it's really 2 watts, not 1). I could be wrong about the technique, though.

 

[trekguy]



Quote:
Originally Posted by ratm /forum/post/18175820


HTD Level 3Max. Power Handling: 150 watts

Frequency Response: 45 Hz - 40 kHz

Impedance: 8 ohms

Sensitivity: 89dB


Jamo Center 100 .


Power (W, long/short term) 70 / 100

Sensitivity (dB, 2.8V/1m) 88

Frequency Range (Hz) 100 - 20,000

Impedence (Ohm) 8

I would think that since the HTD has a higher sensitivity it should be the opposite. Correct?

All things being equal the HDT should be perceived as just barely louder at the same volume control setting. However, things are rarely equal.


Speaker specs are often not very accurate and because the test conditions are not given, comparisons are difficult.


Let's look at what you have.


FR--Neither includes any information about the variation from flat, i.e., +/- X dB. So one could of them could have a peak or sag in an range such as the human voice that you hear as louder or softer. The alleged difference in low end might be audible depending upon your bass management settings.


Sensitivity--There is to my knowledge no FTC rule or this and that leaves makers free to fiddle with the variables.

Tested in an anechoic chamber to avoid room effects? It should be, but many makers try to avoid that expense.

Is full band pink or white noise used or are test tones used. Speaker impedance often varies with frequency and by carefully selecting the test material the results can be optimized.


Microphone positioned relative to the drivers. Shifting the mic position slightly relative to the tweeter and midrange can change the measured SPL.


What microphone or meter was used and when was it calibrated? Many of us here use the famous Radio Shack SPL meter for setup, but it is no good for measuring full range response.


There are two other means known to have been used to get the sensitivity spec. calculating it by modeling the drivers, crossover, and enclosure with software or accepting the numbers provided by the off-shore OEM supplier.
The 2.8 V figure is used because it is simply and directly measurable. Power (watts) is calculated using the formula P= (V x V)/R. Of course as mentioned, earlier the exact impedance is not necessarily the stated nominal impedance.


With this amount of gray area in the spec, it is not surprising that what you hear in the room seems different from the specification.

 

[ratm]

Dont get me wrong, the new speaker sounds amazing and I can definately tell a difference in sound quality, its just that i seem to raise the volume more to get the same perceived sound level